L7224A,C; L7248A,C,L Oil and Electric Boiler Electronic Aquastat Controllers

Transcription

1 L74A,C; L748A,C,L Oil and Electric Boiler Electronic Aquastat Controllers APPLICAION he L74A,C and L748A,C,L 0 Compliant Electronic Aquastat Controllers provide electronic temperature sensing in a UL limit-rated control with a single sensing probe. he L74A,C and L748A,C,L control the circulator, oil or electric burner or contactor, and boiler temperature. he L74/L748 is Outdoor emperature Reset ready which is enabled when connected to the W875Y000 wireless or W875S000 wired Outdoor Reset Kit. Outdoor Reset with the L74/L748 is intended for all applications except for tankless coil systems for domestic hot water. Compliance to 0 DOE regulation ensures efficiency is maximized without interfering with domestic hot water demand. he L74A,C and L748A,C,L replace the L84A, L84C, L74A,C, L748A and L848A Controllers. he L74A,C and L748A,C,L series controls provide status and diagnostic information through an LED display combined with LED lights as well as EnviraCOM communications enabled thermostats and diagnostic tools to enhance the diagnostic process. L74/L748 Aquastat Controllers are intended for use in residential-type applications. INSALLAION INSRUCIONS IMPORAN Use of Outdoor emperature Reset on a tankless coil application requiring a Low Limit setting will result in reduced system effectiveness and efficiency. SPECIFICAIONS Electrical Ratings: Voltage: 0 Vac, 60 Hz. Power: 7 VA maximum at 0 Vac plus external loads. hermostat current: 00 ma nominal at 4 Vac. Burner Relay: 7.4 A at 0 Vac Full Load Amperage (FLA); 44.4 A inrush Locked Rotor Amperage (LRA); Less Ignition Load: 60 VA. Circulator Relay: 7.4 A at 0 Vac FLA; 44.4 A inrush LRA. Zone Controller (): 7.4 A at 0 Vac FLA; 44.4 A inrush LRA. NOE: All loads combined cannot exceed 000 VA. Environmental Ratings: emperature: -0 F to +50 F (-4 C to +66 C). Humidity: 0 to 95% relative humidity, noncondensing. Approvals: Underwriters Laboratories Inc. Component Recognized. Canadian Underwriters Laboratories Inc. Component Recognized. 0 DOE Compliance and Operation Operation of this control may delay the burner operation while the residual heat is circulated out of the boiler. NOE: his operation may be different than earlier electronic Aquastat revisions which did not implement thermal purge

2 L74A,C; L748A,C,L OIL AND ELECRIC BOILER Accessories: W875Y000 Wireless Outdoor Reset Kit W875ER000 Wireless Outdoor Reset Module C7089R0 Wireless Outdoor emperature Sensor (requires W875ER000) W875S000 AquaReset Outdoor Reset Kit (includes Outdoor Reset Module and C7089U006 Outdoor emperature Sensor) W875S008 AquaReset Domestic Hot Water Kit (includes Domestic Hot Water Module and Sensor) W875S000 EnviraCOM Alarm Module C7089U006 Outdoor emperature Sensor (used with the ) emperature Sensor (used with ) Sensor (See able ) Heat Conductive Compound. 7AA Sensor Well Clamp. able. Wells for L74A,C; L748A,C,L Controllers. Part Number Spud Size in. (mm) Insertion in. (mm) able. Sensors for L74A,C and L748A,C,L Controllers. Insulation in. (mm) 869A / (.7) NP (76.) -/ (8.) 870A /4 (9.05) (76.) -/ (8.) NP Part Number Length in. (mm) Application (04.8) Well-mounted controls (609.6) Flush-mounted (94.4) controls (9.) INSALLAION When Installing this Product.... Read these instructions carefully. Failure to follow them could damage the product or cause a hazardous condition.. Check the ratings given in the instructions and on the product to make sure the product is suitable for your application.. he installer must be a trained, experienced service technician. 4. After installation is complete, check out product operation as provided in these instructions. 5. Set High Limit, Low Limit and Low Limit Differential to the settings recommended by the boiler OEM. 6. Record the maximum High Limit setting from the replaced controller in the text box provided on the cover insert label. 7. Record the High Limit setting at time of installation in the text box provided on the cover insert label. WARNING Electrical Shock Hazard. Can cause severe injury, death or property damage. Disconnect power supply before beginning installation to prevent electrical shock or equipment damage. Mounting he L74A,C and L748A,C,L models are available in a well-mount, horizontal position, vertical position, or flush mounted remote from the well versions. Dimensions for the variety of mounting options are shown in Fig.. Note that each identity will have only a single mounting option. /4 (75) 7-/8 (8) 6-/ (66) 5-/6 (45) -/ (77) /8 (0) -/6 (0) -/8 (9) -5/8 (67) 4-/4 (09) -/ (86) /6 () -/6 (5) x /4 (7) x /8 (9) M47B Fig.. L74A,C; L748A,C,L mounting dimensions in inches (mm)

3 L74A,C; L748A,C,L OIL AND ELECRIC BOILER IMPORAN Immersion well must fit sensing element and sensor must rest against bottom of well. New Installation Order well assemblies separately; see able and form no , Immersion Wells and Compression Fittings for emperature Controllers. Boilers usually have tappings that allow the well to be mounted horizontally so boiler water of average temperature can circulate freely over the well.. urn off all power and drain the boiler, if applicable.. If no tapping is provided, prepare properly sized and threaded tapping near the top of the boiler.. Sparingly coat the well threads with pipe dope. NOE: Do not attempt to tighten by using the case as a handle. 4. Install the well in the boiler tapping and tighten securely. 5. Refill boiler and check for water leakage. 6. Loosen but do not remove the well clamp screw. 7. Fit the case into the well so the clamp on the case slides over the flange on the well. 8. Securely tighten the clamp screw. 9. Insert the sensor element into the well until it bottoms. See Replacement Sensor Installation section for details. (If necessary, slightly bend the wire inside the case to hold the sensor against the bottom of the well.) 0. urn power ON.. Set High Limit, Low Limit and Low Limit Differential to the settings recommended by the boiler OEM. (See OPERAION section.) (See INSAL- LAION steps 6 and 7.). On L748L models, adjust ELL option to match your configuration (see OPERAION section, and Fig. and ). IMPORAN Best thermal response is obtained with a well that snugly fits the sensor. Insert the sensor until it rests against the bottom of the well. Use a well of correct length and bend the wiring, if necessary, to hold the bulb against the bottom of the well. If the well is not a snug fit on the sensor, use the heat-conductive compound (furnished with RADE models) as follows: Fold the plastic bag of compound lengthwise and twist it gently. hen snip off end of bag and work the open end of the bag all the way into the well. Slowly pull out the bag while squeezing it firmly to distribute compound evenly in the well. Bend the wiring, if necessary, to hold the sensor against the bottom of the well and to hold outer end of the sensor in firm contact with the side of the well. See Fig.. Wipe excess compound from the outer end of the well. WIRES CONROLLER CASE BOILER IMMERSION WELL CLAMP IMMERSION WELL CLAMP SCREW IMMERSION WELL Fig.. Position of sensor in immersion well. Flush-Mounted Aquastat Replacement urn off all power and remove the old control. Refer to the cover insert of the old control to identify and tag each external lead as it is disconnected. If the old well is unsuitable for the new installation, remove it and replace it with a suitable new well. If the old well is suitable, use it. Well-Mounted Aquastat Replacement HEA-CONDUCIVE COMPOUND (OPIONAL) M60 urn off all power and remove the old control. Refer to the cover insert of the old control to identify and tag each external lead as it is disconnected. If the old well is unsuitable for the new installation, remove it and proceed with instructions for new installation. If the old well is suitable, use it.. Loosen, but do not remove, the well clamp screw on the side of the control case.. Position immersion well clamp snugly over the flange of the adapter and tighten the clamp screw.. Insert the sensor into the well as shown in Fig. or. (See Replacement Sensor Installation section for details.) HERMOSA ERMINALS DISPLAY L L C B C B FUSE ENVIRACOM M ERMINALS CONNECOR HOLES M86 Fig.. Circuit board, showing sensor connection and well holes for horizontal mount models

4 L74A,C; L748A,C,L OIL AND ELECRIC BOILER WIRES WIRING BOILER IMMERSION WELL WARNING Electrical Shock Hazard. Can cause serious injury or death. Disconnect power supply before making wiring connections to prevent electrical shock or equipment damage. Fig. 4. Replacement sensor installation. Replacement Sensor Installation urn off all power and:. Carefully disconnect sensor from circuit board by pulling gently on the connector.. Gently pull sensor from thermo well and through circuit board by pulling on leadwires.. Carefully align replacement sensor with hole in circuit board and guide through Aquastat case and into well. (See Fig. 5). 4. Make sure sensor is fully seated to bottom of well (See Fig. 4). Use a small pencil to measure depth of sensor in well, if necessary. 5. Connect sensor to circuit board by pressing connector on sensor unit into mating connector on circuit board (See Fig. 5). 6. For remote sensors (flush-mounted Aquastat Controllers) be sure to use 57AA Clamp (see Accessories) to securely hold sensor in place. L L C B C B Fig. 5. Circuit board, showing sensor connection and well holes for vertical mount models. Fuse HERMOSA ERMINALS HEA-CONDUCIVE COMPOUND (OPIONAL) ENVIRACOM M ERMINALS DISPLAY M06 CONNECOR RELAYS HOLES FUSE M87 he Amp fuse located near the transformer is intended to protect the EnviraCOM circuit from incorrect wiring. he Aquastat will continue to function should the fuse blow or be removed though no EnviraCOM communication will be possible on the bus and Err 6 will be displayed. See able 0. All wiring must comply with local electrical codes and ordinances. Do not exceed the specifications in the Application section when wiring this control. Use wire rated for 94 F (90 C) or higher. IMPORAN he terminals on these Aquastat Controllers are approved for use with copper wire only. Follow the appropriate wiring diagrams shown on the inside of the front cover of the L74A,C; L748A,C,L or in Fig. 8. Refer to Fig. 6 for Connections for the optional Outdoor Reset Module and the Domestic Hot Water (DHW) module. In subsequent wiring diagrams these modules will be displayed with a dotted line signifying that they are optional. L L C B C B Fig. 6. Wiring the Outdoor Reset Module and the Domestic Hot Water Module. OPERAION General W875Y000 OR W875S000 OUDOOR RESE MODULE (W875S000 SHOWN) O O C7089U006 OUDOOR W875S008 DOMESIC HO WAER MODULE S S EMPERAURE M496 he L74A,C and L748A,C,L Oil Electronic Aquastat Controllers are primary safety limit-rated devices designed for use with oil fired boilers with line voltage burners and circulators. Many boilers do not include wiring or control compartments as part of the design, but are provided with an integral, replaceable, immersion well that is the mounting hardware for the Aquastat Controllers. Wiring to the other controls is done through flexible metal conduit. For boilers that do include a remotely (flush) mounted control, the wiring may be completed with conduit or routed behind the boiler sheet metal

5 L74A,C; L748A,C,L OIL AND ELECRIC BOILER A separate electromechanical high-limit is not required in a system that uses this control to meet Underwriters Laboratories Inc. requirements for oilfired boiler assemblies, UL 76. On the L74 models, the High Limit, Low Limit, Low Limit Differential, and Anti Short-Cycle time can be adjusted to the setting recommended by the boiler OEM. On the L748 models, the High Limit, and Anti Short-Cycle time are also adjustable, see Adjusting Settings. he overall range of the High Limit is from 0 F to 40 F (54 C to 6 C). Select devices may have different ranges. Some models have limited ranges on the High Limit setpoint; this limited range is listed on the device label. Some models also have a Low Limit and Low Limit Differential adjustment. he range of the Low Limit is from 0 F to 0 F (4 C to 04 C). Select devices may have different ranges. he Zr setting can be set to DHW, Zoning, or for tankless coil applications depending on the L74/L748. If an Outdoor Reset Module is installed, the reset curve can be set by entering the minimum outdoor temperature, minimum (boiler) temperature, and maximum outdoor temperature on the -digit display. he range of the minimum outdoor temperature is from -40 F to 40 F (-40 C to 4.4 C) and has a default setting of 0 F (-8 C). he range of the maximum outdoor temperature is from 0 F to 70 F (-. C to. C) and has a default setting of 40 F. he range of the minimum (water or boiler) temperature is from 80 F to 80 F (6.7 C to 8. C) and has a default setting of 0 F. See the Outdoor Reset Module Installation Instructions (form number 69-5) for more information on setting the boiler reset curve and all related parameters. he L74A,C and L748A,C,L are designed for use with 4 Vac electronic and electromechanical thermostats or EnviraCOM enabled thermostats, and have screw-type terminals for easy field connection. Adjusting Settings o discourage unauthorized changing of Aquastat settings, a procedure to enter the ADJUSMEN mode is required. o enter the ADJUSMEN mode, press the UP, DOWN, and I buttons (Refer to Fig. 5) simultaneously for three seconds. Press the I button until the feature requiring adjustment is displayed: able. Adjustable Features. Display Definition HL_ High Limit. Hdf High Limit Differential. LL_ Low Limit. (L74A, C) Ldf Low Limit Differential (L74A, C) ELL External Low Limit (L748L only) duu input configured as external Domestic Hot Water (DHW) request (ON/OFF) (L74A,C/L748L) ASC Anti Short-Cycle imeout (seconds); OFF is disabled. otl* Outdoor emperature Low (minimum) parameter for the outdoor reset curve ( F or C) oth* Outdoor emperature High (maximum) parameter for outdoor reset curve ( F or C) btl* Boiler emperature Low (minimum) parameter for outdoor reset curve bp* Boost Period (minutes). OFF is displayed if Boost is inactive bs* Boost step ( F or C) shown only if Boost is active (bp=on) UUS* Warm Weather Shutdown emperature ( F or C) tpl** hermal Purging Limit emperature ( F or C), OFF if disabled tpt** ermal Purging ime Delay (minutes), shown only if tpl is enabled PC Pump Cycling (ON / OFF) F-C emperature units ( F or C) * Settings available for adjustment on the -digit display only if a W875Y000 or W875S000 Outdoor Reset Kit is installed. **Settings available for adjustment only when the W875Y000 or W875S000 Outdoor Reset Kit is NO installed. hen press the UP and/or DOWN buttons to move the set point to the desired value, to change between F and C, or to enable (On) or disable (Off) the External Low Limit. After 60 seconds without any button inputs, the control will automatically return to the RUN mode. Display In the RUN mode, the Aquastat will flash bt (boiler temp) followed by the temperature (i.e., 0), followed by F or C. o read boiler settings, press the I key to read the parameter of interest. For example, press I and High Limit (HL) is displayed, followed by a three-digit number, i.e., 0, followed by F or C. Pressing the I button again (on L74 models) will display the Low Limit (LL) followed by a three-digit number and the corresponding degree designator. See Display Readout, able 4. After approximately 60 seconds without any key presses, the display will enter a dim display mode. o return to the bright display mode, simply press any key

6 L74A,C; L748A,C,L OIL AND ELECRIC BOILER able 4. Display readout definitions. ext Description Display Err Error Code (if one is present) Err b Boiler emperature bt HL High Limit HL HdF High Limit Differential HdF LL Low Limit (L74 only) LL Ldf Low Limit Differential (L74 only) LdF tt Local hermostat Status tt tte EnviraCOM hermostat Status tte brn B (Burner) output (ON or OFF) brn Cir C (Circulator) output (ON or OFF) Cir Zr ELL duu (Zone Control) output (ON or OFF) (Zone Request) Call for HEA (ON or OFF) External Low Limit Enabled (L748L only) Configured as Domestic Hot Water Request (L74, L748L only) C r ELL dvv ASC Anti Short-Cycle imeout ASC bsp Boiler Set-Point bsp dhc dhc DHW Module Connected (YES or NO) ot Outdoor emperature ot otl Outdoor emperature Low otl oth Outdoor emperature High oth btl Boiler emperature Low btl bp Boost Period bp bs Boost Step bs UUS UUS Warm Weather Shutdown emperature Display shows local setting; not the setting as modified by an external enviracom control. Settings are viewable only if the outdoor reset module and outdoor temperature sensor are installed and functioning properly. Settings are viewable only if the domestic hot water module and sensor are installed and functioning properly. Operation he L74 and L748 models can be in any of four operational states: Normal, High Limit, Low Limit and Error. he controller moves back and forth from High Limit to Normal to Low Limit state as part of normal operation. Only devices having High Limit settings are restricted to the High Limit and Normal states. However, the controller will enter the Error state when there is an abnormal condition. he operating states are:. Normal: Boiler temperature went below the High Limit setting (minus the Differential) and has not exceeded the High Limit setting; or, the boiler temperature went above the Low Limit setting and has not gone below the Low Limit setting (minus the Differential); or, input is not powered with 0 Vac (only L748L with ELL set On).. High Limit: Boiler temperature went above the High Limit setting and has not dropped below the High Limit setting (minus the Differential).. Low Limit: Boiler temperature went below the Low Limit setting (minus the Low Limit Differential) and has not gone above the Low Limit setting; or, input is powered with 0 Vac (only L748L with ELL set On). 4. Error: he controller has detected an error condition (e.g., open sensor) and has shut down the burner output. he output is energized. he controller continues to monitor the system and automatically restarts if the error condition clears. Refer toable 4. he operating sequence for the L74/L748 is shown in able 6 9. High Limit Controller he High Limit opens and turns off the burner when the water temperature reaches the setpoint. he High Limit automatically resets after the water temperature drops past the setpoint and through the Differential. he L748 models have High Limit Differential presets of 5 F (8 C). he L74 models have High Limit Differential presets of 0 F (6 C). Low Limit and Circulator Controller On a temperature rise, with the adjustable Differential at the default setting of 0 F (6 C), the burner circuit breaks and the circulator circuit makes (assuming no call for heat is present) at the Low Limit setpoint. On a temperature drop of 0 F (6 C) below the Low Limit setpoint, the burner circuit makes and the circulator circuit breaks. See Fig

7 L74A,C; L748A,C,L OIL AND ELECRIC BOILER HIGH LIMI SEING LOW LIMI SEING L74: 0 F (6 C) DIFFERENCE L748: 5 F (8 C) DIFFERENCE 0ºF (6ºC) DIFFERENCE Fig. 7. Setpoints and differentials. Anti Short-Cycle Feature SWICH BREAKS ON EMPERAURE RISE. BURNER URNS OFF. CIRCULAOR OPERAES ON A CALL FOR HEA. SWICH MAKES ON EMPERAURE FALL. BURNER OPERAES ON A CALL FOR HEA. WIH NO HEAING DEMAND, SWICH BREAKS ON EMPERAURE RISE. SWICH MAKES ON EMPERAURE FALL, BURNER IS ON O MAINAIN MINIMUM WAER EMPERAURE. CIRCULAOR IS OFF. WHEN WAER REACHES LOW LIMI SEING, HE BURNER SHUS OFF OR HE CIRCULAOR PUMP SARS (WHEN CALLING FOR HEA). M64 he Anti Short-Cycle feature allows for field selection of a delay time between burner cycles. Should a call for heat occur following the end of the previous heat cycle and before the Anti Short-Cycle delay time is expired, the circulator will be allowed to run, but the burner will be held off until the time has elapsed. he range of the Anti Short-Cycle time is from OFF to five minutes. NOE: his feature is blocked if a Domestic Hot Water demand occurs. Domestic Hot Water demands are serviced immediately, without any delay. NOE: When the Aquastat is connected to the oil primary and/or thermostat via the EnviraCOM bus, the Anti Short-Cycle time does not apply to recycle events such as loss of airflow or flame. It applies only to loss of demand. -Domestic Hot Water (DHW) Request he terminal can be selected to service an indirect water heater heat request. his parameter is set via the digit display (see Adjusting Settings section of this document). A heat request via the terminal will have priority over all other features such as the Anti Short-Cycle feature or those enabled by the Outdoor Reset Module (See form #69-5 for more information). Frost Protection he Frost Protection function protects the boiler and potentially the boiler plumbing from possible damage which may occur should the water in the system begin to freeze. he Frost Protection feature is enabled only in the L748 (cold start models). he feature default setting is enabled (ON), but can be disabled using the -digit display. See Adjusting Settings on page 5. When the Boiler temperature drops to the Frost Protection Limit temperature (fixed 40 F), the burner is forced on. he Circulator and outputs remain in the same state as before the Frost Protection function was enabled. hey can be either ON or OFF during the Frost Protection cycle. When the Boiler temperature reaches the Frost Protection Limit temperature plus a fixed 0 F differential, the burner is turned off unless requested to stay on due to a different demand. hermal Purge Operation he intent of thermal purge is to insure usable residual heat in the boiler is circulated until it is sufficiently depleted from the system before the burner is allowed to fire. o that end, on a call for heat, the burner is held off while the circulator runs until the boiler temperature drops to the thermal purge temperature or a time delay is exceeded. Both of these parameters are adjustable. When the boiler temperature reaches the thermal purge temperature, the burner is allowed to fire. hermal purge is only applied to cold start Aquastat models (L748) and will not interfere with domestic hot water call for heat or boilers equipped with Honeywell outdoor reset accessories. For warm start models where a Low Limit must be set, thermal purge is not applied. In addition to the thermal purge temperature and thermal purge time delay parameters, two other conditions release the Aquastat from thermal purge in order to maintain comfort in the space: he boiler temperature has dropped 0 F from the beginning of the thermal purge. Boiler temperature is cooling at a rate greater than 5 F/minute while the circulator is running. he thermal purge feature applies to single zone as well as multi-zone applications. hermal Purge Settings Some thermal purge parameters are configurable using the digit display. See Adjusting Settings on page 5. hermal purge may be disabled by setting the thermal purge temperature limit to "OFF". able 5. hermal Purge Settings. Parameter name Minimum value Maximum Value Default Boiler temperature drop Not adjustable Not adjustable 0 F hermal purge temperature limit 0 F (or OFF) 60 F 40 F (L748) hermal purge temperature rate of drop Not adjustable Not adjustable 5 F/minute hermal purge time delay minute 0 minutes minutes

8 L74A,C; L748A,C,L OIL AND ELECRIC BOILER hermal Purge and Domestic Hot Water he thermal purge feature is automatically disabled whenever there is a call for domestic hot water either from the Zr terminal or from the DHW Module to insure hot water is available in a timely manner. See -Domestic Hot Water (DHW) Request on page 7. Pump Cycling he Pump Cycling feature exercises the system pump for 5 seconds after a non-adjustable five day period of no boiler activity. he Pump Cycling feature default setting is enabled (ON) but can be disabled (OFF) using the -digit display. See Adjusting Settings on page 5. CHECKOU Put the system into operation and observe at least one complete cycle to make sure that the controller operates properly. See ROUBLESHOOING section to use LED to assist in determining system operation. ROUBLESHOOING When attempting to diagnose system performance, reference to the LED display can help to identify specific areas not working properly. he LED display will scroll Err, followed by a digit (-8). Refer to able 0 and for a description of each error and suggested actions. W875Y000 OR W875S000 O O L (HO) L (HO) L INDIREC ANK AQUASA INDIREC ANK CIRCULAOR L C7089U OUDOOR CIRCULAOR L L C B OIL BURNER RELAY C B OUDOOR RESE MODULE IS OPIONAL. W875S000 WIRED OUDOOR RESE MODULE SHOWN. FOR BES PERFORMANCE SE DUU= ON. M0A Fig. 8. L74A,C; L748L single heat zone with indirect water tank and circulators. Optional Outdoor Reset Module

9 L74A,C; L748A,C,L OIL AND ELECRIC BOILER able 6. L74/L748 Controller Operating Sequence. Action System Response hermostat calls for heat. Circulator starts when water temperature is above Low Limit setting (if applicable) or above the hermal Purge emperature Limit (tpl) if hermal Purge is enabled. Boiler temperature is checked. Burner starts when water temperature is below High Limit setting minus the differential or at or below the hermal Purge emperature Limit (tpl) for cold start boilers if the hermal Purge emperature Limit is enabled. If tpl is enabled, the burner may also start if the boiler temperature is cooling at 0 ºF or greater per minute or the hermal Purge ime Delay (tpt) has expired. If Anti Short-Cycle ime is enabled, the burner does not start until the set Anti Short-Cycle ime between cycles expires after the previous call for heat was satisfied. Boiler temperature exceeds the High Limit. Burner is turned off. Burner restarts when the water temperature drops below the High Limit setting minus the Differential. If hermal Purge is enabled, the burner is turned on when either the hermal Purge emperature Limit is reached, the hermal Purge ime Delay has expired or the boiler temperature cooling rate exceeds 0 ºF/minute. hermostat is satisfied. Circulator and burner turn off. Boiler temperature drops below the Low Limit setting minus the differential (if applicable). Error condition -5. Error condition 6. Error condition 7. Error condition 8. Error condition 9*. Error condition 0*. Error condition *. * Error condition only available when the Outdoor Reset Module is installed. Burner is turned on, Circulator is turned off. Burner stops when the water temperature exceeds the Low Limit setting. Power to Zc is removed. If an error condition is detected, all outputs except are shut down. Burner is off. Control continues to function and restarts when error is corrected. During the error check sequence, the system checks for drift in the sensor and corrosion in the connections. EnviraCOM communication is not available. he control has reset the High Limit, Low Limit and Differential setting to a default setting and will continue to run at those settings. Performance of the system will be degraded. If the error condition is detected, all outputs except are shut down. Burner is off. Control continues to function and restarts when all three user keys have been pressed longer than 60 seconds. System continues to run with no outdoor reset functionality System continues to run with outdoor reset parameters enabled as programmed. Error cleared automatically. System continues to run with boiler temp set to High Limit

10 L74A,C; L748A,C,L OIL AND ELECRIC BOILER able 7. L74/L748 Controller Operating Sequence with multiple zones connected through the terminal. Action System Response Zone Request () terminal is connected to L (Zone calls for heat). Boiler temperature is checked. Burner starts when water temperature is below High Limit setting or at or below the hermal Purge emperature Limit (tpl) for cold start boilers if the hermal Purge emperature Limit is enabled. If tpl is enabled, the burner may also start if the boiler temperature is cooling at 0 ºF or greater per minute or the hermal Purge ime Delay (tpt) has expired. Anti Short-Cycle ime is applied, see able 6. Boiler temperature exceeds the High Limit. Burner is turned off. Burner restarts when the water temperature drops below the High Limit setting minus the Differential. If hermal Purge is enabled, the burner is turned on when either the hermal Purge emperature Limit is reached, the hermal Purge ime Delay has expired or the boiler temperature cooling rate exceeds 0 ºF/minute. Zone Request input is de-energized (Zones Burner turns off. are satisfied). Boiler temperature drops below the Low Limit setting minus the differential (if applicable). Burner turns on and Zone Control is de-energized. Burner turns off and Zone Control is re-energized when the water temperature exceeds the Low Limit setting.. able 8. Controller Operating Sequence with External Low Limit device connected trough the terminal. Action System Response Zone Request () terminal is connected to L (External Low Limit call for heat). Boiler temperature is checked. Burner starts when water temperature is below High Limit setting. Circulator turns off. Boiler temperature exceeds the High Limit. Burner is turned off. Burner restarts when the water temperature drops below the High Limit setting minus the Differential. Zone Request input is de-energized Burner is turned off. (External Low Limit is satisfied). able 9. L74 Controller Operating Sequence with Domestic Hot Water connected trough the terminal. Action System Response Zone Request () terminal is connected to L (Domestic Hot Water calls for heat). Boiler temperature is checked. Burner starts when water temperature is below High Limit setting. Boiler temperature exceeds the High Limit. Burner is turned off. Burner restarts when the water temperature drops below the High Limit setting minus the Differential. Zone Request input is de-energized Burner is turned off. (Domestic Hot Water is satisfied)

11 L74A,C; L748A,C,L OIL AND ELECRIC BOILER Aquastat Error Code able 0. LED Error Codes. EnviraCO M Alarm Cause/Action Err Aquastat sensor fault; check water sensor. 8 Err ECOM fault; check EnviraCOM wiring. 8 Err Excessive electrical noise or frequency out of range. Hardware fault; replace controller. 8, 58 Err4 B fault; check B wiring/voltage. 64 Err5 Low Line; check L-L, 0 Vac. 59 a Err6 Warning: Fuse; check ECOM wires, replace fuse. 9 Err7 Warning: EEPROM, HL, LL, Hdf, Ldf; reset to default values. N/A Err 8 b Repeated B fault (voltage present at B when output is turned off); check B wiring/voltage. 5 Err9 a Warning: Outdoor Reset System failure; communication to Outdoor Reset Module lost, 50, 5, 49 Outdoor Reset Module failure, multiple outdoor temperature sensors detected on the bus, or outdoor temperature sensor failure. Check EnviraCOM wiring (,, ), check sensor wiring. a Err 0 Warning: Boost Failure; Boost Mode active at least once per cycle for the last 60 consecutive cycles. Check Outdoor Reset curve settings. Err a DHW Module/Sensor failure; communication to DHW Module lost, DHW Module failure, or temperature sensor failure. Check EnviraCOM wiring (,, ), check sensor wiring. a Warnings are generated to enunciate the system is not operating optimally, but the Aquastat is still operating and maintaining boiler temperature. In the instance where an Outdoor Reset Module is used, the warnings may indicate a reset curve setting error one or more features is not running optimally, and the Aquastat is reverting to default settings or has stopped running the Outdoor Reset algorithms. he warnings are cleared when the issue(s) is resolved. b o clear Err 8 condition, depress and hold all three user keys simultaneously for 60 seconds. Err 8 condition clears and display returns to normal. Err 8 condition is designed to catch welded relays on the Aquastat and will normally only occur near end of life for the control. If Err 8 condition has occurred early in the controls life, be sure to check for voltage feedback to B when B should be off and check current draw on b terminal to be sure oil burner is not drawing excessive current. Err 8 condition will keep repeating if B fault is not cleared. System Condition Boiler is cold, house is cold. able. roubleshooting Guide Diagnostic Condition Check Action Display is OFF. 0 Vac System power. urn system power on. Display is ON. 4 Vac - No 4 V; replace control , 47, 48 4 V present; disconnect Boiler starts, check wiring and thermostat. thermostat, short -. 0 Vac at B-B If no, replace control. If yes, check burner and wiring. Refer to Err on display

12 L74A,C; L748A,C,L OIL AND ELECRIC BOILER System Condition Boiler is hot, house is cold. Display is ON. 0 Vac at C-C 0 Vac at C-C, check wiring to pump. Wiring OK, is pump running? If not, replace the pump. If pump is running, check for trapped air or closed zone valves. Boiler below the Low Limit temperature, wait for boiler to go above Low Limit temperature. Boiler is hot, Display is ON. no hot potable water. able. roubleshooting Guide Diagnostic Condition Check Action Boiler above LL? If yes, check for 0 Vac between and L. If no 0 Vac, replace control. If yes, check zone relays, circulators and wiring. ELL setting (L748L only) Set ELL to Off for multizone system (see Fig. ). Set ELL to On for External Low Limit (see Fig. ). Boiler above LL? If yes, check 0 Vac at -L (only L748L with ELL set On) Boiler Demand signal from the water heater (either 0 Vac at -L, or 0 Vac on -; depends on installation and duu setting) If no 0 Vac, check C-C (see above). If yes, check the External Low Limit control. 4 Vac on - (or 0 Vac on -L), check wiring to water heater Wiring OK, check the water heater duu setting Set duu to ON if 0 Vac water heater demand is connected to Set duu to OFF if open/closed water heater demand is connected to - Check DHW Module and DHW Sensor DHW Module not properly connected and/or DHW Sensor improperly positioned ZONE CIRCULAOR R845A RELAY ZONE O ADDIIONAL R845A RELAYS FOR OHER ZONES L L (HO) L74 LOW HERMOSA ZONE LOW HERMOSA POWER SUPPLY. PROVIDE DISCONNEC MEANS AND OVERLOAD PROECION AS REQUIRED. CONROL CASE MUS BE CONNECED O EARH GROUND. USE GROUNDING SCREW PROVIDED. CIRCULAOR OIL BURNER RELAY L L C B C B M75 Fig. 9. L74A,C multizone system with circulator connections

13 L74A,C; L748A,C,L OIL AND ELECRIC BOILER W875Y000 OR W875S000 INDIREC ANK AQUASA O O H94C 6 C7089U006 OUDOOR INDIREC ANK CIRCULAOR R784/R784 LIMI L L (HO) L L74 L L 5 ENVIRACOM ERMINAL BURNER MOOR BURNER MOOR IGNIER IGNIER 7 VALVE VALVE 4 CIRCULAOR L L C O REMOE ALARM CIRCUI CAD CELL CAD CELL JUNCION BOX LEGEND SCREW ERMINAL /4 IN. (6 MM) QUICK CONNEC ERMINAL SOLDERLESS WIRE CONNECION POWER SUPPLY. PROVIDE DISCONNEC MEANS AND OVERLOAD PROECION AS REQUIRED. OPIONAL FEAURE ON SELEC MODELS. B C B 5 ENVIRACOM ERMINAL IS ALSO HE FIRS HERMOSA ERMINAL. 6 OPIONAL OUDOOR RESE MODULE AND OUDOOR. W875S000 WIRED OUDOOR RESE MODULE SHOWN. REFER O DEVICE LABEL FOR WIRE COLOR CODE. 7 DUU MUS BE SE O ON ON HE AQUASA. 4 VALVE IS OPIONAL ON SPECIFIED MODELS. M05B Fig. 0. L74A,C single zone system with circulator and indirect water tank with EnviraCOM thermostat

14 L74A,C; L748A,C,L OIL AND ELECRIC BOILER L (HO) L ELL=OFF O ADDIIONAL R845A RELAYS FOR OHER ZONES R845A RELAY ZONE ZONE CIRCULAOR ZONE LOW HERMOSA L748L LOW HERMOSA ENVIRACOM 4 ERMINALS W875Y000 OR W875S000 O O C7089U006 OUDOOR CIRCULAOR L L C B W875S008 DOMESIC HO 5 WAER MODULE S S OIL BURNER RELAY C B EMPERAURE 4 5 POWER SUPPLY. PROVIDE DISCONNEC MEANS AND OVERLOAD PROECION AS REQUIRED. CONROL CASE MUS BE CONNECED O EARH GROUND. USE GROUNDING SCREW PROVIDED. OPIONAL OUDOOR RESE MODULE AND OUDOOR. W875S000 WIRED OUDOOR RESE MODULE SHOWN. ENVIRACOM ERMINALS. OPIONAL DOMESIC HO WAER MODULE AND EMPERAURE. M9655A Fig.. L748L multizone system with circulator connections

15 L74A,C; L748A,C,L OIL AND ELECRIC BOILER W875Y000 OR W875S000 W875S008 O O S S C7089U 6 OUDOOR EMPERAURE 8 R784/R784 LIMI L L (HO) L L74 MULI-ZONE RELAY PANEL 9 L 5 ENVIRACOM ERMINAL BURNER MOOR BURNER MOOR IGNIER IGNIER VALVE VALVE 4 CIRCULAOR L L C O REMOE ALARM CIRCUI CAD CELL CAD CELL B C B JUNCION BOX LEGEND SCREW ERMINAL /4 IN. (6 MM) QUICK CONNEC ERMINAL SOLDERLESS WIRE CONNECION POWER SUPPLY. PROVIDE DISCONNEC MEANS AND OVERLOAD PROECION AS REQUIRED. 6 OPIONAL OUDOOR RESE MODULE AND OUDOOR. W875S000 WIRED OUDOOR RESE MODULE SHOWN. OPIONAL FEAURE ON SELEC MODELS. 7 OPIONAL DOMESIC HO WAER MODULE. 4 REFER O DEVICE LABEL FOR WIRE COLOR CODE. VALVE IS OPIONAL ON SPECIFIED MODELS. 8 WIRE ONLY HE ENVIRACOM ERMINALS (,, ) ON OIL PRIMARY IF CONNECING O REMOE DIAGNOSICS, OHERWISE CONNEC A JUMPER BEWEEN HE ERMINALS. 5 ENVIRACOM ERMINAL IS ALSO HE FIRS HERMOSA ERMINAL. 9 ZONE PANEL ERMINALS MAY HAVE DIFFEREN LABEL. CHECK PANEL MANUFACURER SPECIFICAIONS FOR WIRING INSRUCIONS. M04A Fig.. L74/L748 multizone system with Outdoor Reset and Domestic Hot Water Modules (indirect tank applications)

16 L74A,C; L748A,C,L OIL AND ELECRIC BOILER ELL=ON L L (HO) R W L6006 LOW LIMI CONROLLER B L748L LOW HERMOSA CIRCULAOR L L C B OIL BURNER RELAY C B POWER SUPPLY. PROVIDE DISCONNEC MEANS AND OVERLOAD PROECION AS REQUIRED. CONROL CASE MUS BE CONNECED O EARH GROUND. USE GROUNDING SCREW PROVIDED. M7 Fig.. L748L External Low Limit connections. Security Warning his product contains electronic hardware and software. No one is authorized to modify the hardware or software. Any modification or tampering could result in any or all of the following: incorrect operation of the product or the appliance, unsafe operation, personal injury, and property damage. Modification or tampering will also make the warranty null and void, and any liability, will have to be borne by the owner, installer, or facility manager. Waste Warning he product should not be disposed of with other household waste. Check for the nearest authorized collection centers or authorized recyclers. he correct disposal of end-of-life equipment will help prevent potential negative consequences for the environment and human health. Home and Building echnologies In the U.S.: Honeywell 75 Peachtree Street NE Atlanta, GA 008 customer.honeywell.com U.S. Registered rademark 08 Honeywell International Inc M.S. Rev. 0-8 Printed in United States