Controls and Safety Devices for Automatically Fired Boilers

Transcription

1 20 Proosed Revision of CD-1 E CD (Revision of E CD ) 2015 Controls and afety Devices for utomatically Fired Boilers DRFT DTE: 01/2018 N E R I C N N T I O N L T N D R D Two Park venue New York, NY U

2 E CD C-200 ENERL PROVIION C-210 eneral Provisions as Code, for gas-fired boilers and with NFP 31, tandard for the Installation of Oil-Burning Equiment, for oil-fired boilers. (b) Louvers and grilles shall be fixed in the oen osition or interlocked with the equiment so that they are oened automatically during equiment oeration. The interlock shall be laced on the driven member. (c) Fans sulying air to the boiler room for combustion shall be interlocked with the burner so that air flow is roven during equiment oeration. Installation requirements shall aly to controls, safety devices, and burners on automatically fired boilers covered by this tandard. For information regarding boiler and/or burner installations, refer to local codes. In the absence of local codes, see NFP 54/NI Z223.1 for gas-fired boilers and NFP 31 for oil-fired boilers. For boilers firing liquefied-etroleum gas or LP-gas air mixtures, the requirements ertaining to the storage container, the first and second stage LP-gas ressure regulators, and all comonents ustream of the oint of gas delivery (see C-700) are covered by NFP 58, Liquefied Petroleum as Code. (15) C-300 TERIL REQUIREENT C-310 Comonents Each control and safety device covered by this tandard shall be acceted for the intended service by a nationally recognized testing agency such as, but not limited to, UL, F, or C (see C-230). C-220 Installation (a) Installation of controls, safety devices, and burners shall be in accordance with the manufacturer s instructions and the alicable requirements of this tandard. C-400 TETIN ND INTENNCE Diagrams detailing the wiring and iing connections for the controls and safety devices installed shall be C-410 Cleaning furnished by the unit manufacturer [see C-510(c)]. anufacturers of controls and safety devices requir(b) Installations shall rovide accessibility for removing eriodic service shall furnish detailed instructions ing burners; adjusting, cleaning, and lubricating workcovering the rocedures and frequency of cleaning [see ing arts; and relacing controls, safety devices, and C-510(c)]. if required to adjust the ilot and/or main burner flame. Observation other control comonents. orts roviding the direct visualand observation are not required in the (c) For information concerning location C-420 Testing installation of LP-gas following air mixture boilers, refer to local cases: boilersbyand building codes. (a) boilers using ulse combustion that anufacturers are labeled andof listed a burners covered by this tandard shall furnish detailed instructions for testing (d) When one or more modules of a modular boiler nationally recognized testing agency. controls and safety devices, both when the boiler is (see C-700) are relaced, comatibility of all controls (b) indirect observation is rovided by reflection for visual observation oerating and when it is out of service [see C-510(c)]. and systems shall be ensured. The relacement modules or an indicator driven by a sensor. When used, a sensor and indicator shall comly with theshall initial listing and shall meet the dislay both the resence and absence of the ilot and/or main C-430 aintenance requirements of this tandard. flame. Boiler, boiler unit, and burner manufacturers shall C-230 Observation Ports furnish detailed instructions on maintenance and service Observation orts shall be rovided to ermit direct rocedures for the fuel burning system or electrically visual insection of the ilot, main burner flame, and heated units, including controls and safety devices boiler furnace, excet for boilers using ulse combustion installed with the unit. that are labeled and listed by a nationally recognized These instructions shall include requirements secitesting agency. fying that cover lates, enclosures, and guards shall be maintained in lace at all times, excet during maintec-240 uarding nance (see C-510 and Part C). uards shall be rovided to rotect ersonnel and Boiler, boiler unit, burner, and control manufacturers rotect against damage to control equiment. uarding oeration and maintenance instructions furnished with shall conform to alicable regulations. the equiment shall be retained and made available to the boiler oerator (see C-510). C-250 nnunciator ystems Where used, annunciator systems, and their associated test and acknowledgement circuits, shall have all contacts, switches, relays, and lights arranged so that safety control functions are not byassed. C-440 Oerational Testing (a) The manufacturer of sho-assembled boilers shall test and reort er C-510(a) on the oeration of control systems and safety devices installed in accordance with this tandard. Test conditions shall be as close to secified field conditions as feasible rior to shiment from the manufacturer s facility. Where roduction makes it C-260 Combustion ir (a) The requirements of combustion air shall be in accordance with NFP 54/NI Z223.1, National Fuel 2

3 E CD infeasible to check each sho-assembled boiler unit individually rior to shiment, the manufacturer shall follow a written insection and quality control rocedure by which the intent of this aragrah will be met. (b) The installing contractor shall test and reort er C-510(b) on the oeration of control systems and safety devices installed in accordance with this tandard rior to release to the owner/user. C-500 individual (see C-700) to the owner/user and to obtain a receit for the instructions. The receit shall be filed with the installation reort. C-600 OPERTION C-610 Lockout The manual rocedure required for effecting the restart of the equiment subsequent to a lockout shall be accomlished from a location where the cause of the lockout may be determined so that the necessary corrective action may be erformed to ensure that safe oerating conditions revail before restarting the boiler. afety control(s) that can electronically reset without local manual intervention, such as when ower or control inut to the device is interruted and then restored, shall not be ermitted. CERTIFICTION ND REPORTIN C-510 Certification and Reorting (a) anufacturers of sho-assembled boiler units covered by this tandard shall maintain a reort for each boiler unit or on each category (tye, size, or model) for boiler units. For boiler units less than or equal to 400,000 Btu/hr (117 kw) for gas, or less than or equal to 3 gh (11.4 L/h) for oil, a reort shall be maintained on each category (tye, size, or model). This reort shall list (1) each control and safety device installed in accordance with this tandard (2) name of the manufacturer and model number *NEW DEFINITION: of each control and safety device branch burner:(3)oerational burner that the testtakes-off erformedfrom (see C-440) C-510(a)(1) through (a)(3) shall be verified by the main burner suly line, but does not have its own signature of an authorized reresentative of the rimary safety control, but rather uses the main manufacturer on this reort. n examle of an accetable data burner as it s source ignitionin and safety control reort form isof contained Nonmandatory endix C. (e.g. 2nd stage line burner (ortoie This burner). reort shallbe made available the authorized insection agencyadjacent or the insector for action as required burner) where installed to line by the local jurisdiction. burner and acting as the ignition source of the (b) Installing contractors shall maintain or obtain adjacent line is considered to each be ainstallation branch comfromburner, the manufacturer a reort for of a singleleted. burnerthe assembly. reort shall list (1) each control and safety device installed in accordance with this tandard (2) name of the manufacturer and model number of each control and safety device (3) oerational test erformed (see C-440) C-510(b)(1) through (b)(3) shall be verified by the signature of an authorized reresentative of the installing contractor on this reort. n examle of an accetable reort form is contained in Nonmandatory endix C. This reort shall be made available to the authorized insection agency or the insector for action as required by the local jurisdiction. (c) Installing contractors shall obtain from the boiler manufacturer ertinent oerating, testing, servicing, and cleaning instructions for the controls and safety devices (see C-410, C-420, and C-430). It is the resonsibility of the installing contractor to deliver these instructions, together with comlete wiring and iing diagrams, and a written recaution that the oerating, testing, and servicing only be erformed by a qualified C-700 DEFINITION acceted: a boiler unit, equiment, or device is acceted when listed, labeled, or otherwise determined to be suitable and safe by a nationally recognized testing agency. Field installations are acceted when aroved by the authority having jurisdiction. air change: the quantity of air necessary to comletely relace the air contained in the combustion chamber and associated flue assages. air shutter: an adjustable device for varying the flow of air. alarm: an audible or visible signal indicating an off-standard or abnormal condition. alarm circuit: a circuit that includes an alarm. annunciator: a device that indicates a condition, either normal or abnormal, by visual signals, audible signals, or both. aroved: accetable to the authority having jurisdiction. atomizing media: a sulementary medium, such as steam or air, that assists in breaking the fuel oil into a fine sray. authorized insection agency: the insection agency aroved by the aroriate authority of a state or municiality of the United tates or a rovince of Canada that has adoted this tandard. W: merican Wire auge. bleed line: a section of iing or tubing that conveys the release of gas from a fuel train comonent, which eriodically releases gas ressure to the atmoshere in order to oerate roerly. boiler: a closed vessel in which water or other liquid is heated, steam or vaor is generated, steam or vaor is suerheated, or any combination thereof, under ressure or vacuum for use external to itself, by the direct 3 (15)

4 E CD flame failure resonse time: the time interval between the loss of flame and deenergizing the safety shutoff valve. combustion chamber: the ortion of the boiler enclosure into which the fuel is fed, ignited, and burned (also referred to as furnace or firebox). flue assages (breeching): the cavities (e.g., flue, exhaust, or vent system) that convey the roducts of combustion from the boiler combustion chamber to an aroved location. conductor: a body that may be used to conduct electric current. continuous duty: the design feature of an electrical device, such as a motor, enabling the device to oerate at the rated load for an indefinite eriod. F: factory mutual arovals. fuel train: a series of valves, regulators, and controls, between the burner and the source of fuel, that regulates and controls the flow of fuel to the burner. control: a device designated to regulate the fuel, air, water, steam, or electrical NOTE suly toto the controlled equireviewer: ment. It may be automatic, semiautomatic, or manual. gas: one of the following fuel gases: natural gas, liquefied etroleum (LP) gas, LP-air mixture, manufactured gas, or mixed gas. Definition has other beenthan a control, oerating: an automatic control, safety control, to start orrevised. regulate ee inut according to demand and to sto or regulate inut on satisfaction of ressure regulator, demand. gas-ressure regulator, main: a device for controlling and maintaining a redetermined gas ressure for the main burner. gas, main control, rimary safety: a control directly resonsive to flame roerties, sensing the resence of flame and, in event of ignition failure or loss of flame, causing safety shutdown. gas-ressure regulator, ilot: a device for controlling and maintaining a redetermined gas ressure for the ilot burner. control, safety (also known as limit): a control resonsive to changes in liquid level, ressure, or temerature and set beyond the oerating range to revent the oeration beyond designed limits. gas-ressure relief line: a section of ie or tubing that conveys a release of gas from a gas-ressure relief valve. ground: a conducting connection, whether intentional or accidental, between an electrical circuit or equiment and either the earth or a conducting body that serves in lace of the earth. control manufacturer: an organization that manufactures oerating and safety controls for use on boilers. C: C International. grounded: connected to earth or to some conducting body that serves in lace of the earth. damer: a valve or late for regulating combustion air or flue gases. draft: the difference in ressure between atmosheric and some other ressure in the furnace or gas assages. grounded conductor: a system or circuit conductor that is intentionally grounded. draft, mechanical: the draft caused by a mechanical device, such as a forced draft or induced draft fan. grounding conductor, equiment: the conductor used to connect noncurrent-carrying metal arts of equiment, raceways, and other enclosures to the system-grounded conductor at the service and/or the grounding electrode conductor. draft, natural: the draft caused by the difference in the temerature of the hot flue gases and the outside atmoshere. guarded: covered, shielded, fenced, enclosed, or otherwise rotected by means of covers, casings, barriers, rails, screens, mats, or latforms to revent contact by ersons or objects. dri: the container laced at a low oint in a system of iing to collect condensate and from which condensate may be removed. fan, forced draft: a fan used to suly air, under ressure, to the fuel-burning equiment of the boiler. high fire: the rate of a burner at or near design maximum fuel inut. fan, induced draft: a fan used to exhaust gases, under suction, from the boiler. ignition system, direct: an automatic ignition system that uses an electrically energized device to ignite fuel at a main burner. feedback line: a section of iing or tubing that normally communicates air ressure from a oint of reference to the air ressure side of a diahragm of fuel train comonent, but could contain gas under abnormal conditions; or a section of iing or tubing that communicates flue or gas ressure from one oint of reference to another oint of reference. ignition system, hot surface: an automatic, direct ignition system that uses a hot surface igniter to ignite fuel at a main burner. inut rating: the fuel-burning caacity of a burner at sea level in Btu/hr (W) as secified by the manufacturer. firing rate: the rate at which air, fuel, or an air-fuel mixture is sulied to a burner, exressed in volume or heat units sulied er unit of time. installing contractor: an organization that installs a boiler, combustion controls, burners, and rotective equiment in the field. 5

5 E CD labeled: equiment or materials to which has been attached a label of a nationally recognized testing agency that maintains eriodic insection of roduction of labeled equiment or materials. Labeling indicates comliance with nationally recognized standards. ilot: a small burner that is used to lightoff (ignite) the main burner. ilot, continuous: also known as a constant burning ilot, a ilot that burns without turndown throughout the entire time the burner assembly is in service, whether the main burner is firing or not. liquefied-etroleum gas: fuel gases, including commercial roane; redominantly roane, roylene, or commercial butane; redominantly butane; isobutane; and/or butylene. ilot, intermittent: a ilot that is automatically lighted each time there is a call for heat. It burns during the entire eriod the main burner is firing. listed: equiment or materials included in a list ublished by a nationally recognized testing agency that maintains eriodic insection of roduction of listed equiment or materials. Listing indicates comliance with nationally recognized standards. ilot, interruted: a ilot that is automatically lighted each time there is a call for heat. The ilot fuel is cut off automatically at the end of the main burner flameestablishing eriod. ilot, roved: a ilot flame suervised by a rimary safety control. local: within hysical sight and sound of the affected equiment (see also lockout). lockout: a safety shutdown that requires a local, manual rocedure to restart the equiment (see also shutdown, *Insert new Definition: safety). ilot flame-establishing eriod: the interval of time that fuel is ermitted to be delivered to a ilot burner before the multile burner boiler unit: boiler unit withrimary safety control is required to rove the ilot flame. low fire start: the light-off ignition of achamber burner with thecontains one common combustion and fuel controls in a low fire osition. In a system with ilot manifold gas ressure: the gas ressure measured at more low than assembly, of which guaranteed fireone start,burner interlocks are used toeach revent a location that is secified by the burner/boiler unit has its burner own rimary control. startu if the is not in safety the low fire osition. manufacturer and is taken downstream of the ilot gas-ressure regulator. low-water fuel cutoff: a device that shuts off the fuel when the boiler water falls to an unsafe level. oint of gas delivery: for other than undiluted liquefiedlp-gas air mixture: liquefied-etroleum gases distributed at relatively low ressures and normal atmosheric temeratures that have been diluted with air to roduce a desired heating value and utilization characteristic. etroleum gas systems, the oint of gas delivery shall be considered the outlet of the service meter assembly or the outlet of the service regulator or service shutoff valve when no meter is rovided. For undiluted, liquefied-etroleum gas systems, the oint of gas delivmain burner flame-establishing eriod: thenew interval of time *Insert Definitions: ery shall be considered the outlet of the first stage the main burner fuel safety shutoff valves are ermitted regulator, main: a device for regulator. to be oen before the rimaryressure safety control is requiredgas,lp gas-ressure controlling and maintaining a redetermined to rove the resence of the main burner flame. ool heater: an aliance designed for heating nonotable ressure to theatgas water manifold. stored at atmosheric ressure, such as water in main manifold gas ressure: the gas gas ressure measured a location that is secified by the burner/boiler unitzeroswimming ressure regulator, governor: ools, a mainsas, hot tubs, and similar alications. manufacturer and is taken downstream of the main gas gas ressure regulator that is normally ressure regulator. osturge eriod: a eriod of time after the fuel valves adjusted to deliver gas at atmosheric manifold, gas: the conduit of an aliance that sulies close, during which the burner motor or fan continues ressure within its flow rating. gas to the individual burners. to run to suly air to the combustion chamber and flue assages. manual reset device: a comonent of a control that requires resetting by hand to restart the burner after safe reurge eriod: a eriod of time on each startu during oerating conditions have been restored. which air is introduced into the combustion chamber and flue assages in volume and manner as to comletely relace the air or fuel-air mixture contained therein rior to initiating ignition. maximum fixed sto limit: on a temerature or ressure control having an adjustable set oint, the maximum fixed sto limit is the maximum setting to which the control can be adjusted and still erform its intended function (i.e., safety shutdown) but not be exceeded due to a mechanical or electrical sto device. ressure regulator, LP-gas, first stage: on undiluted LP-gas systems, a ressure regulator designed to reduce ressure from the container to 10.0 si (70 kpa) or less. NE: National Electric anufacturers ssociation. ressure regulator, LP-gas, second stage: a ressure regulator for service on undiluted LP-gas systems designed to reduce first stage regulator outlet ressure to 14.0 in. W.C. (4.0 kpa) or less. NFP: National Fire Protection ssociation. oil: any commercial grade fuel oil as defined by T D396. 6

6 E CD Fig. C-1 ediment Tra ressure regulator, service: a ressure regulator installed by the serving gas sulier to reduce and limit the service line gas ressure to delivery ressure. as suly inlet rimary safety control system: an automatic labeled and listed control that may integrate the functions of other controls, such as oerating control(s), rimary safety control(s), safety control(s), and sensing devices. This control system integrates searate labeled and listed comonents that incororate feedback so that the failure of any of these sensing devices will result in a safety shutdown and lockout condition of the boiler. Tee fitting To gas control(s) inlet roven reurge: a rovision of the control system for reventing burner oeration until rescribed air flow is roven to be established during reurge. Nile ulse combustion: a self-asirating, acoustically resonating combustion system. 3 in. (76 mm) min. qualified individual: a boiler service technician who is engaged in and resonsible for installation, relacement, reair, or service of the boiler, fuel-burning system controls, and safety devices and is exerienced in such work. Ca readily accessible: having direct unimeded access without the need of a ladder or removing or moving any anel, door, or similar covering of the item described. switch, low oil temerature: a temerature-actuated device arranged to sto the flow of fuel to a reheated oil burner or to revent it from starting when the fuel oil temerature falls below a set oint, which shall be the lower end of the viscosity range recommended by the burner manufacturer. recycle: the rocess of sequencing a normal burner start following safety shutdown before the establishment of (INERT NEW DEFINITION) lockout. may: ermissive; not required; an relay: a device that is oerative by a variation in the accomlish conditions ofalternative one electric means circuit toto start the oeration of other devices the same task. or another electric circuit, the in secified such as ressure or temerature relay. switch, low-ressure: a ressure-actuated device to monitor liquid, steam, or gas ressure and arranged to sto the flow of fluid to the burner at a reset low ressure. switch, ressure: a ressure-resonsive device that makes or breaks an electrical circuit and may be automatically or manually reset. relight: the action uon loss of main flame to reestablish the ignition source without recycle. sediment tra: a device in a gas line that collects and revents solid debris (such as ie doe, slag, dirt, etc.) from traveling downstream into the gas controls (see Fig. C-1). time delay: a deliberate delay of a redetermined time in the action of a safety device or control. UL: Underwriters Laboratories, Inc. uer set oint limit: on a temerature or ressure control having an adjustable range of set oints, the uer set oint limit is the maximum ressure or temerature set shutdown, safety: shutting off all fuel and ignition energy oint in the range of the control, to which the control NEWcontrol DEFINITION) to the burner by (INERT means of a safety or rimary can be adjusted and still erform its intended function safety control (seeshall: also lockout). action that is mandatory and(i.e., safety shutdown). shutdown, normal: shutting off fuel and ignition energy to the burner by means of an oerating control. switch, air flow: a device usedtotoaccomlish rove the flowthe of air. required secified task. switch, high oil temerature: a temerature-actuated device arranged to sto theindicates flow of fuelatoreferred a reheatedbut should: oil burner or to revent it from starting when not mandatory means tothe fuel oil temerature rises above a set oint, which shall be the secified task. the uer end of accomlish the viscosity range recommended by the burner manufacturer. switch, high-ressure: a ressure-actuated device to monitor liquid, steam, or gas ressure and arranged to sto the flow of fuel to the burner at a reset high ressure. valve, automatic: an automatic device consisting essentially of a valve and oerator that controls the fuel suly to the burner(s) during normal oeration of a boiler. It may be actuated by alication of electrical, mechanical, or other means. valve, lubricated lug tye: a valve of the lug and barrel tye designed for maintaining a lubricant between the bearing surfaces. valve, modulating control: a valve designed to regulate fuel inut to the burner in resonse to demand. 7

7 E CD (c) otors shall be rovided with running rotection by means of integral thermal rotection, overcurrent devices, or a combination of both in accordance with manufacturer s instructions that shall be based on the requirements of NFP 70, National Electrical Code. (d) otors shall be rated for continuous duty and shall be designed for an ambient temerature of 104 F (40 C) or higher. (e) ll motors shall be rovided with terminal leads or terminal screws in terminal boxes integral with, or secured to, the motor frames. uch wiring shall be in accordance with NFP 70, National Electrical Code. ll wiring between comonents shall have coer conductors not less than size No. 18 W and constructed in accordance with NFP 70, National Electrical Code. (b) ll electrical wiring shall have a voltage rating commensurate with the voltage of the ower suly. (c) Conductors shall be rotected from hysical damage. (d) Conductors shall be sized on the basis of the rated current of the load they suly. CE-140 Ignition ystem (a) When automatic electric ignition is rovided, it shall be accomlished by means of a high-voltage electric sark, a high-energy electric sark, or a hot surface igniter. (b) Ignition transformers shall conform to requirements of UL 506, tandard for ecialty Transformers. (c) Ignition cable shall conform to the requirements of UL 814, as-tube-ign Cable. CE-160 Bonding and rounding (a) eans shall be rovided for grounding the major metallic frame or assembly of the boiler. (b) Noncurrent-carrying enclosures, frames, and similar arts of all electrical comonents and devices shall be bonded to the main frame or assembly of the boiler. Electrical comonents that are bonded by their installation do not require a searate bonding conductor. (c) When an insulated conductor is used to bond electrical comonents and devices, it shall show a continuous green color, with or without a yellow strie. CE-150 Wiring (a) ll wiring for boilers shall be rated for the maximum oerating temerature to which it may be exosed. (INERT NEW REQUIREENT) CE 170 nnunciation, tatus and Control Wiring to Primary afety Control ystems (a) Connections made to the Primary afety Control ystem and connected to an external device for the urose of annunciation, status indication or any other urose shall not: (1) Change the intended oeration or setting of safety or oerating controls. (2) Energize safety related oututs from the Primary afety Control ystem. (b) Connections of any external device as described in CE 170(a) shall be tested and reorted in accordance with C-440(b) by a qualified technician. Testing shall verify safety and oerating controls of the rimary safety control system are not byassed and no safety related oututs from the rimary safety control system are energized as a result of the external connections. 11

8 E CD Part CW team and Waterside Control CW-100 (15) UTOTIC LOW-WTER FUEL CUTOFF ND/OR COBINED WTER FEEDIN DEVICE of the lowest visible art of the gage glass (see also CW-210). ECEPTION: Only one low-water cutoff is required on gravity return units installed in residences, as defined by the authority having jurisdiction. CW-110 eneral Requirements for Water Level Controls for ll Boilers water feeding device, when used, shall be constructed and installed so that the water inlet valve cannot feed water into the boiler through the float chamber or its connections to the boiler. The water feeding device shall be located to maintain the oerating water level. (b) The electrical circuit shall be connected in such a manner that either low-water fuel cutoff control will shut off the fuel or energy suly to the boiler when a low-water condition develos. One cutoff control shall be set to function ahead of the other. (1) With a umed condensate return, functioning of the lower of the two cutoff controls shall cause safety shutdown and lockout. The manual reset may be incororated in the lower cutoff control. Where a reset device is searate from the low-water fuel cutoff, a means shall be rovided to indicate actuation of the low-water fuel cutoff. The manual reset device may be the instantaneous tye or may include a time delay of not more than 3 min after the fuel has been cut off. (2) With gravity condensate return, the lower of the two cutoff controls shall be electrically connected with the uer cutoff to cause a safety shutdown requiring manual reset only when the uer cutoff has failed to function. (c) The fuel cutoff device may be inserted internally or attached externally to the boiler. n external cutoff device may be attached to iing connecting a water column to the boiler or combined with a water column. Water column iing and connections shall be at least NP 1 (DN 25). If the lower water fuel cutoff is connected to the boiler by ie or fittings, no shutoff valves of any tye shall be laced in such iing. cross, or equivalent fitting, shall be laced in the water iing connection at every right angle to facilitate cleaning and insection. Fuel cutoff devices embodying a searate chamber shall have a vertical drainie and blowoff valve, not less than NP 3 4 (DN 20), located at the lowest oint of the chamber or water-equalizing ie connections so that the chamber and equalizing ie can be flushed and the device tested. (d) low-water fuel cutoff or combined feeder/cutoff device may also be installed in the taed oenings (a) Each low-water fuel cutoff or combined feeder/ cutoff device shall conform to UL 353, tandard for Limit Controls, and ll shalllow be acceted by a nationally recognized testing agency. (b) Installation diagrams and instructions shall be furnished by the manufacturer. (c) Low-water fuel cutoffs or combined feeder/cutoff ll to rovide access for servicing, devices shall be located reairing, testing, and insection. (d) The low-water fuel cutoff shall have a ressure rating at least equal to the maximum allowable working ressure of the boiler. (e) In robe-tye, low-water fuel cutoffs, an oen circuit failure, break, or disconnection of the electrical comonents or conductors in the safety circuit shall revent continued oeration of the firing mechanism. (f) larms, when used, shall be distinctly audible above the ambient noise level and may be used in conjunction with indicating lights. They shall be located to alert the oerator or an individual trained as to what action to take when an alarm indicates a otentially dangerous situation is develoing. (g) Low-water fuel cutoffs of the automatic or manual reset tye shall be electrically connected in accordance with CE-110(j). (h) For vacuum boilers, see the requirements in CW-700. CW-120 Requirements for Water Level Controls for Low-Pressure team or Vaor ystem Boilers (a) Each automatically fired, low-ressure steam or vaor system boiler shall have at least two automatic low-water fuel cutoffs, one of which may be a combined feeder/cutoff device. When installed external to the boiler, each device shall be installed in individual chambers (water columns), which shall be attached to the boiler by searate ie connections below the waterline. common steam connection is ermissible. Each cutoff device shall be installed to revent startu and to cut off the boiler fuel or energy suly automatically, rior to the fall of the surface of the water below the level 12

9 E CD (d) system may incororate a time delay comonent with the low-water fuel cutoff device to revent short cycling. This comonent shall not constrict any connecting iing, and the time delay shall not exceed the boiler manufacturer s recommended timing, or 90 sec, whichever is less. The device shall cut off the fuel or energy suly when the water falls to the lowest visible art of the gage glass. CW-150 Requirements for Oerating and afety Controls for Electrically Heated Boilers Electric resistance and electrode boilers shall have a boiler feed control system that shall maintain the oerating level in steam boilers and oerating water ressure on hot-water boilers. Where uncovering of the electrical element can lead to an unsafe condition, the boiler shall be rovided with low-water fuel cutoff(s) in accordance with Part CW. Boiler feed control and lowwater fuel cutoff may be common to one control. In the case of electrode-tye boilers, where the reduction in water level rovides a self-limiting control on inut, low-water fuel cutoff controls are not required. CW-200 UTOTIC FUEL CUTOFF FOR FORCED CIRCULTION BOILER CW-210 Requirements for Flow or Temerature ensing Devices for Forced Circulation Boilers a b (a) In lieu of the requirements for low-water fuel cut offs in CW-100, a boiler, requiring forced circulation to revent overheating and failure of the heat exchanger (tubes, coils, etc.) shall have one or more of the following means to revent burner oeration at a water flow rate inadequate to rotect the boiler unit against overheating UL 353 at all allowable firing rates: (1) a flow sensing device labeled and listed by a recognized testing agency as a safety control comlying with the requirements of CW-110(a). This safety control shall be indeendent of any other oerating controls. (2) a rimary safety control system comrised of a labeled and listed rimary safety control and temerature sensing devices that function to monitor temerature rise across the boiler unit such that inadequate flow rate can be determined by excessive temerature rise. The listing of the rimary safety control system shall comly with the requirements in CW-110(a). Uon detection of an inadequate flow rate, the means secified in (a)(1) or (a)(2) shall shut down the burner and revent restarting until an adequate water flow rate is restored. Positive means shall be rovided to determine during testing that these controls functioned uon an inadequate flow condition. The ositive means shall enable these controls to remain in the running safety lock circuitry during testing. The safety control must be automatically restored to service after comletion of system testing. (b) When there is a definitive waterline, a low-water fuel cutoff device comlying with the alicable ortions of CW-100 shall be rovided in addition to controls necessary for meeting the requirements of CW-210(a). Functioning of the low-water fuel cutoff shall cause a safety shutdown and lockout. CW-300 PREURE CONTROL CW-310 Requirements for Pressure Controls for team Boilers (a) Each boiler ressure control shall conform to UL 353, tandard for Limit Controls, and shall be acceted by a nationally recognized testing agency. (b) Each automatically fired steam boiler or system of commonly connected steam boilers shall have at least one steam ressure control device that will shut off the fuel suly to each boiler or system of commonly connected boilers when the steam ressure reaches a reset maximum oerating ressure. This requirement does not reclude the use of additional oerating control devices where required. (c) In addition to the ressure control required in (b) above, each individual automatically fired steam boiler shall have a high steam ressure limit control that will In addition to a low-water fuel revent generation of steam ressure greater than the cutoff as allowable secifiedworking in CW-110 and maximum ressure. Functioning of this control ashall cause safety shutdown and lockout. CW-130, The manual reset may be incororated in the ressure limit control. Where the reset device is searate from the ressure limit control, a means shall be rovided to indicate actuation of the ressure limit control. Each *INERT* limitmay and oerating control shall have its own sensing and be automatically reset element and oerating switch. when adequate flow is restored. ECEPTION: Lockout is not required for boiler units installed in residences, as defined by the authority having jurisdiction. (d) ressure limit control of the automatic or manual reset tye shall be electrically connected in accordance with CE-110(j). This(e) control may allow the boiler to No shutoff valve of any tye shall be laced in recycle. the steam ressure connection between the boiler and the high-ressure limit control device and steam ressure control device or between the boiler and steam (b) ressure control device. (f) Each ressure control device shall be rotected with a sihon,off or the equivalent of maintaining a fuel ormeans energy suly water seal, that will revent steam from entering the control. The minimum size of a sihon shall be NP 1 4 (DN 8). Tubing suitable for the temeratures and ressures involved, with an inside diameter at least equal to standard ie sizes, may be substituted for ie. When a control incororating a mercury switch is mounted on the sihon, the loo of the sihon shall be in a lane that is 90 deg (1.57 rad) from the lane of the mercury switch. 14 (15)

10 E CD cut off the fuel suly at or below the (g) team ressure suly connections to a single control. The high temerature limit control s sensing ressure control using ie of nonferrous material shall element shall be ositioned on the boiler to revent the not be less than NP 1 4 (DN 8) for lengths u to and boiler water temerature from exceeding the maximum including 5 ft (1.5 m) and not less than NP 1 2 (DN 15) allowable temerature. The uer set oint limit or the automaticallyforfired hot-water or Tubing each system of the maximum fixed sto limit of the high temerature limit lengths over 5 ftboiler (1.5 m). suitable for commonly connected boilers shallhaving haveanatinside least two temeratureshot-water and ressures involved, control shall not exceed the maximum allowable temerdiameter at least equal to that of standard ie, may be ature. Functioning of this high temerature limit control temerature control devices which substituted for ie. shall cause safety shutdown and lockout. The manual (h) team ressure suly connections to a single reset may be incororated in the high temerature limit ressure control using ie of ferrous material shall not control. Where a reset device is searate from the high be less than NP 1 2 (DN 15) for lengths u labeled to and includtemerature limit control, a means shall be rovided to and listed ing 5 ft (1.5 m) and not less than NP 1 (DN 25) for indicate actuation of the high temerature limit control. lengths over 5 ft (1.5 m). Tubing suitable for the temeraeach high temerature limit control shall have its own tures and ressures involved, having an inside diameter *INERT* sensing element and oerating switch. The sensing eleat least equal to that of standard ie, may be substituted ment may be remote from control unit. the This requirement doesthenot reclude for ie. use of additional control ECEPTION: Lockout istemerature not required for boilers installed in resi(i) Pressure controls should have searate ressure dences, as defined byare the authority having jurisdiction. devices which not labeled and listed to connections; however, manifolding is ermitted. When multile controls are fed from a manifold, the manifold the 353, tandard for Limit Controls. (d)ul Requirements in CW-410(b) and CW-410(c) may be and common source connection to the boiler, for ie fulfilled by acceted integrated controls with multile of nonferrous material, shall not be less than NP 1 2 sensors and oerating switches. The integrated control s (DN 15) for lengths u to and including 5 ft (1.5 m) and multile sensors may be individually ackaged or intenot less than NP 3 4 (DN 20) for lengths over 5 ft (1.5 m). grated into a single ackage. For manifolds using ferrous material, the manifold and (e) Each high temerature limit and oerating temcommon source connection to the boiler shall not be less erature control shall have its own sensing element and than NP 3 4 (DN 20) for lengths u to and including oerating switch, unless the boiler temerature and limit 5 ft (1.5 m) and not less than NP 11 4 (DN 32) for lengths control functions are erformed by a rimary safety over 5 ft (1.5 m). Individual controls are to be ied control system meeting all the requirements of from the manifold according to the rovisions of CW-210(a). The sensing element(s) may be remote from CW-310(g) and (h). their control unit(s). (j) The uer set oint limit or maximum fixed sto (f) Each required control of the automatic or manual limit of the ressure control selected shall not exceed reset tye shall be electrically connected in accordance the maximum allowable working ressure of the boiler. with CE-110(j). (g) No shutoff valve or isolation device of any tye shall be laced between the boiler and the boiler s concw-400 TEPERTURE CONTROL trols as required in CW-410(b) and CW-410(c). (15) CW-410 Requirements for Temerature Controls for Hot-Water Boilers ECEPTION: shutoff valve or isolation device may be installed oerating temerature between the boiler and the oerating temerature control(s) secified in CW-410(b) rovided (a) an acceted safety control is installed to monitor for sufficient waterat flow in the one system and is interlocked with the boiler control least to revent firing if the water flow is insufficient as determined by the boiler manufacturer, or (b) an acceted valve osition suervisory device ensures the valve is oen and is interlocked with the boiler control to revent firing if the isolation valve is not fully oen. (a) Each temerature control device shall conform to UL 353, tandard for Limit Controls, and shall be acceted by a nationally recognized testing agency. (b) Each automatically fired hot-water boiler or each system of commonly connected hot-water boilers shall have at least one oerating temerature control. (1) This temerature control shall have its own sensing element and oerating switch. The temerature control s sensing element shall be ositioned so it senses the system water temerature to shut off the fuel or energy suly when the water reaches a reset oerating temerature. The sensing element may be remote from the control unit. (2) This requirement does not reclude the use of additional temerature controls. (c) In addition to the control requirements in CW-410(b), each individual automatically fired hot-water boiler shall have a high temerature limit CW-500 FETY ND FETY RELIEF VLVE CW-510 Requirements for team and Hot-Water Heating Boilers The safety and safety relief valves of all steam and hot-water heating boilers shall conform to the E Boiler and Pressure Vessel Code, ection I or IV, as alicable. 15

11 [aroximately 400,000 Btu/hr (117 kw)] Table CF-2 400,000 Btu/hr (117 kw) and maller (Power as Burners, echanical Draft tmosheric as Burners, and Pulse Combustion ystems), 3 gh (11.4 L/h) and maller (Oil) (15) Pilot Ignition as afety Control Continuous Pilot Intermittent Pilot Direct Ignition ystem Interruted Pilot as Hot urface Ignition Oil as Only None None None None Pulse combustion: four air changes at 60% damer oening with both damer oening and air flow roven [Note (3)] None None Pilot flame-establishing eriod None 15-sec maximum 15-sec maximum Not alicable Not alicable Not alicable ain burner flame-establishing eriod None None 15-sec maximum 15-sec maximum Pulse combustion: 4-sec maximum 30-sec maximum 15-sec maximum 180-sec maximum Not alicable 4-sec maximum Not alicable 4-sec maximum 4-sec maximum Not alicable 4-sec maximum Not alicable 30-sec maximum Not alicable 4-sec maximum Valve closing time None 5-sec maximum after de-energization 5-sec maximum after de-energization 5-sec maximum after de-energization Not alicable 5-sec maximum after de-energization ction on ilot flame failure afety shutdown afety shutdown [Note (1)] afety shutdown [Note (2)] Not alicable Not alicable Not alicable ction on main burner flame failure None None afety shutdown [Note (2)] afety shutdown [Note (2)] Pulse combustion: u to 3 recycles ermitted before safety shutdown afety shutdown [Note (2)] afety shutdown Fuel ressure suervision Not required Not required Not required Not required Not required Not required Flame failure resonse time [Note (2)] Pilot ain burner 19 ENERL NOTE: Timings shown above reresent the maximum rimary safety control timings ermitted by this tandard. The model designation of the installed rimary safety control together with the timings shall be rovided in the documentation of the burner/boiler. NOTE: (1) fter safety shutdown, wait a minimum 5-min time delay before resetting ignition system (instructional requirement). (2) If ignition system includes a relight feature, one relight attemt shall be initiated within 0.8 sec uon loss of flame. (3) For damers with a fixed mechanical sto, see CF-210(a)(1) and (a)(2). E CD Purge requirements [Note (1)]

12 (15) Table CF-3 afety Controls for utomatically Fired Units: Power as Burners, echanical Draft tmosheric as Burners, and Pulse Combustion ystems afety Control Purge requirements reater Than 400,000 Btu/hr (117 kw) and Less Than or Equal to 2,500,000 Btu/hr (733 kw) reater Than 2,500,000 Btu/hr (733 kw) and Less Than or Equal to 5,000,000 Btu/hr (1 465 kw) reater Than 5,000,000 Btu/hr (1 465 kw) and Less Than 12,500,000 Btu/hr (3 663 kw) Four air changes at 60% damer oening with both damer oening and air flow roven [Note (1)] Four air changes at 60% damer oening with both damer oening and air flow roven Pilot flame tye and establishing eriod Continuous Interruted Intermittent 15 sec (initial start only) 15 sec 15 sec Not ermitted 10 sec Not ermitted Not ermitted 10 sec Not ermitted ain burner ignition tye and establishing eriod Pilot only: 15-sec maximum if interruted ilot used Interruted ilot only, 10-sec maximum Direct ignition system: 4-sec maximum [Note (2)] Hot surface ignition system: 4-sec maximum [Note (2)] Interruted ilot only, 10-sec maximum Direct ignition system: 4-sec maximum [Note (2)] Hot surface ignition system: 4-sec maximum [Note (2)] Direct ignition system: 4-sec maximum Hot surface ignition system: 4-sec maximum 21 Flame failure resonse time 4-sec maximum 4-sec maximum 4-sec maximum Valve closing time 5-sec maximum after de-energization 1-sec maximum 1-sec maximum ction on flame failure afety shutdown and lockout or recycle once Pulse combstion: u to 3 recycles before safety shutdown and lockout afety shutdown and lockout [Note (3)] afety shutdown and lockout [Note (3)] ction on ower or control inut interrution after safety shutdown and lockout anual reset required in accordance with C-610 *INERT* anual reset required in accordance with C-610once [Note (2)] or recycle anual reset required in accordance with C-610 Proven low fire start Not required ee CF-610 ee CF-610 Combustion air roving action on loss of combustion air Required: safety shutdown and lockout or recycle Required: safety shutdown and lockout Required: safety shutdown and lockout Fuel ressure suervision Not required for ignition systems with ilots. Required for direct ignition and hot surface ignition systems: high and low gas ressure arranged to cause safety shutdown and lockout. Required: high and low gas ressure arranged to cause safety shutdown and lockout Required: high and low gas ressure arranged to cause safety shutdown and lockout ENERL NOTE: Timings shown above shall be within the tolerances established by the nationally recognized testing agency where the rimary safety controls are labeled and/or listed [see CF-310(c) and CF-510(c)]. NOTE: (1) For damers with a fixed mechanical sto, see CF-210(a)(1) and (a)(2). (2) aximum inut at light off shall be less than or equal to 2,500,000 Btu/hr (733 kw). (3) Pulse combustion not ermitted for alications with inuts greater than 2,500,000 Btu/hr (733 kw). E CD Four air changes in 90 sec, or at 60% damer oening, with both damer oening and air flow roven [Note (1)] Instructional requirement: minimum 5-min shutoff before lighting constant ilot

13 If the high gas-ressure switch is located downstream of the main gas ressure E CD regulator, the main or boiler Relace (e) with (d) Relace (f) with (e) Relace (g) with (f) inletinsert ressure ":"of the nearest ustream gas-ressure regulator. When the high gas-ressure switch is located downstream of the safety shutoff valve(s), the high gasor burners (h) without ressure switch shall be caable ofrelace withstanding damage a ressure not less thanwith 50%(g) above its uer set oint limit or 5 sig (35 kpa), whichever is greater. (h) as-ressure switches of the automatic or manual Insert ttachment reset tye shall be electrically connected in accordance contents on the next with CE-110(j). (b) ressure switch used to monitor high gas ositive ressure shall function to cause safety shutdown and lockout before the manifold gas ressure exceeds (1) the boiler/burner manufacturer s secified high gas-ressure switch setting for the listed boilers, or (2) 150% of the boiler/burner s main manifold gas ressure if the setting is not secified The high gas-ressure switch shall be located downstream of the service ressure regulator and may be located downstream of all main burner gas-suly controls. (c) ressure switch used to monitor low gas ositive ressure shall function to cause safety shutdown and lockout before the manifold gas ressure is less than (1) the boiler/burner manufacturer s secified low gas-ressure switch setting for the listed boilers, or (2) 50% of the boiler/burner s main manifold gas unit ressure if the setting is not secified The low gas-ressure switch shall be located ustream of the safety shutoff valve(s). When the low gas-ressure switch is located ustream of the main gas-ressure regulator, the burner shall be labeled and listed by a nationally recognized testing agency for this arrangement. (d) For burner/boiler units with zero or negative main gas manifold ressure sulied by a combination gas valve with internal negative gas-ressure regulator function, high gas-ressure suervision shall be accomlished by a ressure switch located ustream of the safety shutoff valve(s), and downstream of the boiler/ burner unit s gas service ressure regulator. The ressure switch shall function to cause safety shutdown and lockout before the service ositive ressure exceeds (1) the setting of the overressure rotection device in CF-161, if equied (2) the boiler/burner manufacturer s secified high gas-ressure switch setting for listed boilers, or (3) 150% of the boiler/burner s secified maximum gas suly ressure if the setting is not secified boiler/burner unit incororating listed zero governor combination gas valve(s) that cause safety shutdown and lockout if the combination gas valve s gas regulator fails is deemed to meet the intent of the requirements for high gas-ressure suervision. (e) Pressure test ort(s) shall be rovided to ermit NEW CF-180(b)(3). measuring theinsert gas ressure(s) to confirm comliance with the requirements of this aragrah.b (ee ee TTCHENT (f) as-ressure switches shall be labeled the age following the and listed by a nationally recognized testing agency. "TTCHENT " age) (g) as-ressure switches shall be caable of withstanding without damage a ressure not less than 10% above the relieving ressure of the nearest ustream relief device. Where no relief device is rovided, the Relace (c) with (e) gas-ressure switches shall be caable of withstanding without damage a ressure not less than the maximum age for the revised CF-170 text. Control Valves (a) n automatic inut, comlete closure, control valve may be combined with a safety shutoff valve. Fora single burner (b) byass to rovide for minimum flame may be installed around a valve used to control inut only. Boiler units, the main byass shall not be installed around a safety shutoff valve or a combination inut control and safety shutoff valve. CF-180 afety hutoff Valves (a) Each main burner and ilot burner suly line shall be equied with a safety shutoff valve(s) that shall comly with the alicable rovisions of NI Z21.21/C 6.5, utomatic Valves for as liances, NI Z21.78/C 6.20, Combination single burner as Controls for as liances, or UL 429, tandard for Electrically Oerated Valves. (b) The burner suly line shall be equied as indicated below for the alicable inut classification or any greater inut classifications: (1) For boiler units having inuts less than or equal to 5,000,000 Btu/hr (1 465 kw), the main burner suly line shall be equied with at least two safety shutoff valves in series that may be in a single valve body or one safety shutoff valve with a valve seal overtravel (roof of closure) interlock function. If the two safety shutoff valves are in a single valve body, the two safety shutoff valve seats shall be in series and shall have indeendently oerated valve shafts. (2) For boiler units having inuts greater than 5,000,000 Btu/hr (1 at 465least kw) one and less than 12,500,000 Btu/hr (3 663 kw), the main burner suly line shall be equied with at least two safety shutoff valves in series that may be in a single valve body. t least one of the two safety shutoff valves shall incororate a valve seal overtravel (roof of closure) interlock function. If the two safety shutoff valves are in a single valve body, the two safety shutoff valve seats shall be in series and shall have indeendently oerated valve shafts. When the inut of a branch gas suly is greater than 2,500,000 Btu/hr (733 kw), the branch valve requirements are determined by the branch inut. (c) The ilot gas suly line shall be equied with a safety shutoff valve that shall comly with the alicable rovisions of NI Z21.21/C 6.5, utomatic Valves for as liances; NI Z21.78/C 6.20, 23