CFP4, 8 or 12 Exde Immersion Heater CERTIFIED TO IEC 60079-0:2000, IEC 60079-1:2001 and IEC 60079-7:2001 PD455 048422-303 November 2012
Installation Instructions Health and Safety Attention is drawn to the Health and Safety at Work Act regulations and also any other appropriate statutory requirements or by-laws. These place responsibility for complying with specific safety requirements on the manufacturer and user. Hazardous Environments The heater must be installed by suitably trained personnel in full accordance with IEC 60079-14:2007. This standard defines the code of practice for the safe installation of electrical equipment in hazardous areas other than mines. NO WORK SHOULD BE UNDERTAKEN UNTIL ALL HAZ- ARDS ARE REMOVED OR REDUCED TO AN ACCEPT- ABLE LEVEL No operation involving the use of an open flame or other source of ignition should be attempted until the condition has been made safe (gas free) by the control of the flammable material that may give rise to the risk. Electrical test equipment can constitute a hazard and should not be used in the presence of a flammable material, unless specifically designed for the purpose and suitably certified. Electric Shock The electrical supply to the equipment must be switched off before removing covers from any unit where lethally high voltages may be present. General Safety Precautions Ensure that the area safety supervisor and others in the vicinity are aware that work is being undertaken and post warning notices. Ensure that the appropriate safety equipment and clothing is worn. Beware of wet or slippery ladder rungs and working areas if working aloft. The terminal enclosure covers are locked closed using two M4 socket head cap screws; these must be undone before attempting to unscrew the cover or serious and irreparable damage may be made to the flamepath threads. The enclosure covers have the following weights: CFP4 15kgs, CFP8 19kgs, CFP12 38kgs This must be borne in mind when removing or replacing a cover during maintenance work. General CFP4, 8 and 12 Immersion Heaters are constructed in accordance with the requirements and specifications of Certificate IECEx ITS 03 0007X. The equipment may be used with flammable gases and vapors with apparatus group II, T1 T6 or 560 C or 600 C. The standard certified ambient temperature range is 50 C to + 40 C, an extended range of -50 C to + 60 C is available with the increased terminal box stand-off distances shown in table below. (The values given are Chromalox standard stand-off distances which in all cases exceed the minimum distances required for each temperature class. Full details are given in the certificate drawings.) T Class 40 C Ambient Stand-off T Class 60 C Ambient Stand-off 600 C 310mm 600 C 330mm 560 C 270mm 560 C 290mm T1 240mm T1 240mm T2 190mm T2 190mm T3 125mm T3 140mm T4 90mm T4 90mm T5 90mm T5 90mm T6 90mm T6 90mm In certain exceptional circumstances, the marked Temperature Class on the equipment may be exceeded either on the heater mounting flange or at the exit point of the process vessel under the designed operating conditions. This matter must be fully understood and addressed by the user with the appropriate risk assessments carried out before commissioning the equipment. 2 Each heater is manufactured with great care from the highest quality materials and thoroughly inspected before leaving our works. They must be handled with care and stored in dry conditions as befits any electrical apparatus and not exposed to wet or damp atmospheres. Before installation and commissioning it is advisable that the elements be checked to ensure that the insulation readings are above 2 MH per element at 500 volts dc. If there is an unacceptable low reading on any of the elements, it will be necessary to dry them out. For the detailed procedure, please refer to the Maintenance section. The certification of this equipment relies on the following materials used in its construction: Cast iron Carbon steel Stainless steel Copper Brass Neoprene O-ring seals The performance of these materials with regard to attack by aggressive substances shall be taken into account when installing in the hazardous area. PRESSURE EQUIPMENT STATEMENT This immersion heater has been manufactured, tested and inspected in accordance with the Sound Engineering Practice (SEP). Refer to the pressure equipment nameplate or drawings for details of the fluid, maximum allowable working pressure, maximum working temperature and hydrostatic test pressure. For details of the Fluid Category, Maximum Allowable Pressure, Maximum Working Temperature and the Hydrostatic
Test Pressure, please refer to the Check List For The Essential Safety Requirements Of The Pressure Equipment Directive produced for this heater (or heater and vessel assembly) where applicable. The heater should NOT be mounted outdoors where exposed to the weather, or where it is likely to suffer severe shock/vibration or explosive/hazardous atmospheres or corrosive/dust laden environments, unless it has been specifically designed for the application. When installing heaters, sufficient clearance must be allowed for access to the terminal enclosure and to enable the heater bundle to be withdrawn from the tank or pressure vessel. If the heater is to be mounted in the side of a tank, it should be near to the bottom but with sufficient clearance to prevent any chance of sludge or sediment on the tank base from coming into contact with the heating elements. If the immersed length of the heater exceeds one metre, it will be necessary to provide a means of support to prevent the elements sagging or imposing excessive load on the tank wall. Where the heater is vertically mounted, the ends of the elements should be sufficiently clear of the tank to avoid any deposits of sludge or sediment. Ensure that the mains supply available corresponds with the supply voltage on the heater nameplate and ensure that the size of supply cables, fuses and contactors are adequate for the electrical load they carry. When selecting the cable glands for the incoming supply, it is important to be aware that the internal volume of all three enclosure sizes exceeds 2 liters. Control System Specification for Heaters Located in Hazardous Areas Where the electric heater is installed in a Zone 1 hazardous area, it is necessary, in order to satisfy the requirements of IEC 6206/IEC/EN13849-1 and IEC60947-1, 4 &5 to control it using a single fault tolerant control system. It is the installer and/or users responsibility to ensure that the following safety requirements are complied with in full. 1. In addition to the usual process temperature control, all type G2 and L immersion heaters shall be fitted with, or controlled by, an over temperature cut-out device to ensure that the process temperature and therefore the surface temperature of the flange does not exceed the values given in Table 1. 2. All type G1 heaters shall either be rated by design for continuous operation without need for a cutout (convector or anti-condensation heaters) or as in the case of air heaters, be fitted with suitable temperature sensors clipped to the element sheath. Such sensors shall be attached at the hottest point within the heater, usually on the air-off side at the top of the unit with a minimum of one fitted per phase on two of the phases of the firston, last-off stage. The trip temperature of the sensors shall be set no higher than the values given in Table 1. TABLE 1 G2 & L Classified Heaters G1 Classified Heaters T6 80 C T6 Not Permitted T5 95 C T5 75 C T4 130 C T4 110 C T3 195 C T3 175 C T2 290 C T2 270 C T1 440 C T1 420 C 560 C 550 C 560 C 520 C 600 C 590 C 600 C 570 C When setting the trip temperature, it is important to establish beforehand, the long-term reliability of the sensor being used and any degree of set-point drift which may occur over time. This must then be deducted from the value given in Table 1 to ensure that the limiting temperature appropriate to the relevant T Class is not reached or exceeded under any foreseeable circumstances. Mechanical temperature limiting devices (cut-outs) and temperature controlling devices (thermostats) may be fitted inside the heater terminal enclosure, in an adjacent auxiliary junction box forming part of the heater or separately within the process environment. Over temperature sensors such as thermocouples or RTDs are usually fitted via the process flange and terminated in a separate terminal housing. Sensors, either mechanical or electrical, must be of an established proven design and comply with the requirements of EN 954-1 3. It is recommended that earth fault protection, (suitable for the firing method) be incorporated in the control system. 4. When using contactor control, it is necessary to provide a back-up contactor; one for control, the other not normally operating for trip purposes. 5. Where SCR / SSR devices are used for power regulation, a common trip relay shall be used to interlock power supply to SCR driver instrument or primary to trigger card circuitry. 6. Where the control system is employing a PLC, over temperature sensors must act directly on the heater power supply and not rely on the instrument for safe shut down. 7. The over temperature system for Exde heaters must operate in all abnormal conditions and is required in addition to, and be independent from, any control system that may be necessary for the normal operation of the equipment. 8. The protective systems of Exde certified equipment should de-energize the heater either directly or indirectly. They must be of the manual re-set type and re-setting must only be possible with the aid of a tool when the unit has returned to its normal operating condition. In the event of a sensor failing, the control instrument must respond by de-energizing the heater. 9. The entire control system including all over temperature cut-outs must be inspected periodically to confirm functionality and accuracy. The frequency of such inspections will be determined by experience and by manufacturer s reliability data relating to the system components. 3
Pre-Installation Checks Check that the heater certification category of IIC is appropriate to the area classification of the intended application. Check that the surface temperature class is correct. The heater temperature class is stamped on the terminal box label. Check that the apparatus carries the correct circuit identification. The electrical and certification details of the heater are stamped on the terminal box nameplate. Check that the condition of all enclosures, seals and joints are satisfactory. Water and other corrosive fluids must not get into flameproof box threads. These should be lightly lubricated with an approved copper based anti-seize compound. Ensure that screwed connections and fasteners are complete and tight. Check that the electrical circuits agree with the heater wiring diagram and all electrical connections are tight. Installation The silica gel desiccant, which is placed inside the terminal box at the factory, should not be removed until just prior to installation. During no process conditions the anti-condensation heater (where fitted) should be energized. Connect the electrical supply and earthing cables, ensuring they are routed so as not to impose undue stress on the connections or press against other terminals. Sufficient electrical clearance must exist between all conducting components of differing potential (i.e. phase to phase or phase to earth). Similarly, connect control wiring ensuring that compensating cables have the correct polarity, (i.e. positive to positive). Care should be exercised to ensure that the international color coding for compensating cables are fully understood by installation personnel, and their requirements followed Incoming cables must be connected to the terminations by means of cable lugs and secured from loosening or twisting, so that the contact pressure is permanently maintained. Check that a sufficiently good earth connection is made to the heater by means of the earth facility provided in the terminal enclosure. Earthing is to comply with the requirements of IEC 60079-14:2007. Supply cables must be suitable for a maximum terminal enclosure of 70 C. and suitable certified glands should show no signs of damage and should be adequate for both the stated electrical duty and the required standard of ingress protection. Where the heater is divided into several control stages, the overheat cut-out device, must be wired into the first heater stage, i.e. the stage which is continuously switched on whilst the heater is energized. It must be wired into the control system in series with the coil of the main contactor, such that complete shut down of the heater is ensured in the event of overheating and the supply cannot be reenergized until the system is reset. If more than one cut-out device is fitted, these must be wired in series. The apparatus should be adequately protected against mechanical damage, extreme temperatures and other adverse conditions. The air gap (stand-off) between the flameproof terminal box and the heater flange must not be lagged or closed off. The purpose of the stand-off is to ensure that the temperature inside the terminal box does not exceed 70 C under normal design and operating conditions. This area requires free air circulation at all times during operation and failure to comply with this requirement will invalidate the equipment certification. Ensure that the electrical protection is satisfactory. Cables Electrical Checks Electrical Checks Prior To Start Up Insulation Resistance (Megger) The megger should be applied between phase and earth, with any control supplies disconnected from the power supply, the insulation resistance shall be measured with a voltage of not less than 500Vdc and should be above 2 MW divided by the number of heating elements. Should the insulation resistance be below this value, then the elements should be individually checked for insulation resistance to identify those that will need drying out. For the detailed procedure, please refer to the Maintenance section. Continuity Check that the ohms reading per phase are approximately equal and correct. 4
Commissioning Ensure that the operating conditions for which the heater was designed are prevailing, set the over temperature trips upscale and the process controller to the required operating temperature. Apply power to the heater via the control panel. Once the heater is operating in a steady condition, the over temperature trip device should be wound down until the heater trips out. The temperature should be noted as being the actual safe running temperature and the control device turned up by approximately 20 C to allow for process fluctuations. This setting will then be the trip temperature and must be locked by what ever suitable means to prevent unauthorized change. The trip temperature of the sensors shall be set no higher than the values given in the following. G2 & L Classified Heaters G1 Classified Heaters T6 80 C T6 Not Permitted T5 95 C T5 75 C T4 130 C T4 110 C T3 195 C T3 175 C T2 290 C T2 270 C T1 440 C T1 420 C 560 C 550 C 560 C 520 C 600 C 590 C 600 C 570 C General Ensure that the system is filled with fluid. It is essential that the heated portion of the elements is fully immersed before power is switched on. If this requirement is not maintained it will result in premature failure of the heater and is not the responsibility of the supplier or the manufacturer. All foreign matter must be removed from the system before initial use of the heater system. Failure to remove such matter may cause a potential hazard and result in serious damage if carried through the system to the heating elements. Where an anti-condensation heater is fitted inside the heater terminal box, it must be de-energized before switching on the heater supply. Fault Finding If the control system cycles or trips during initial start up there may be insufficient flow. In the event of a shutdown caused by overheating, the MAIN ISOLATOR MUST BE SWITCHED OFF BEFORE any checks are made. The pipe work should be checked for obstructions of the flow, any filters/strainers (if fitted) checked for blockage and the control system inspected to determine the cause of the overheating BEFORE the unit is put back into operation. Do not forget to re-set the thermal cut-out within the terminal enclosure by pushing in the reset button on the device where such a unit is fitted. Inspection Periodically inspect all terminal connections and visible insulation for damage, looseness, fraying and defects as applicable. Retighten any loose terminal lugs and replace or repair damaged or deteriorated insulation. Temperature sensors should be checked for operation and replaced if necessary. Check all cabling for visible damage and check tightness of termination nuts, fittings and glands. Check the condition of the flameproof terminal box and apply a light coating of an approved copper based anti-seize compound to all flamepath threads. Thermal device housings and junction boxes should also be inspected where fitted. During annual shutdown periods or whenever convenient, unbolt heater from its mating flange and check the condition of the heating elements. Discoloration due to overheating should be reported and any product build up on the surface of the element should be cleaned off using highpressure steam, water jets or suitable solvent as appropriate. Check that the ohms per phase on each stage are approximately equal and correct. If they are not, check each element individually to establish those with unacceptable readings which will need replacing. If the heater has been shutdown for any length of time, the heating elements should be examined to ensure that the insulation and continuity readings are satisfactory. If there is an unacceptably low insulation reading on any of the elements, it will be necessary to dry them out using the following procedure or by returning the complete heater bundle to Chromalox for drying out at the Chromalox factory. 5
Element Replacing Chromalox heating elements are designed and manufactured to provide a long trouble-free life and rarely fail if they are operating in the conditions for which they were designed. However, should replacement be necessary the heater has been designed to make this a simple and straightforward operation. Isolate heater from electrical supply, together with the ancillary supplies to control devices and anticondensation heater (where fitted). Slacken off the M4 socket head cap screws, which will unlock the lid of the flameproof enclosure and enable the lid to be unscrewed and removed. Disconnect all cabling from the heater terminal box. Unbolt and dismantle the busbars, then unscrew the element flameproof glands from the flameproof box base. Replaceable Elements Replaceable U Bend Elements Unbolt the stand-off nuts holding the terminal box to the flange, and then remove the terminal box using the threaded spigot on the top of the casting to fit an M20 x 2.5 lifting eye. On no account should this be used to lift the entire heater, flange-lifting points are provided for this purpose. Having drained the tank or vessel, unscrew the nuts on each of the flange stud bolts and pull the flanged heater away from its mating flange, taking care not to damage the baffles or heating elements. Remove the top nuts from the two mechanical fittings (using special tool Extended Reach Socket Spanner) securing the element needing replacement. This will enable the element to be pushed through the flange enough to expose the two bite olives. Cut through the element between each olive and the flange, enabling the element to be withdrawn back through the flange and baffle assembly. The new element should be checked electrically before fitting using two new olives and following the reverse procedure. Note that the internal sharp edge in the olive should go on first and ensure that the ends of the new element protrude through the flange by the same amount as the other elements. The coupling body should be tightened to a maximum torque of 60 foot pounds force (81.5Nm) using the Extended Reach Socket Spanner special tool. The top nuts should be tightened down finger tight, plus one and a quarter turns, which is equivalent to a torque of 35 foot pounds force (47.5Nm). The flanged heater should be re-fitted in the vessel using a new gasket. The studbolt nuts must then be tightened uniformly and in a diametrically staggered pattern. Refit the terminal box, flameproof glands and busbars using the reverse procedure. The brass nuts holding the busbars to the element terminations should be tightened to 1.8 foot pounds force (2.5Nm). All flamepath threads should be lubricated with copper anti-seize compound. Refit the supply cabling to the heater terminal box and reconnect the thermal control devices where fitted. Lubricate the main flameproof box thread with copper based anti-seize compound and screw on the lid (fitted with its o-ring gasket) then lock with the M4 socket head cap screws. These Inspection Withdrawable Cartridge Elements Before the terminal box can be removed, it may be necessary to squeeze together the element terminals so that they will pass through the element holes in the base of the enclosure. Unbolt the stand-off nuts holding the terminal box to the flange, and then remove the terminal box using the threaded spigot on the top of the casting to fit an M20 x 2.5 lifting eye. On no account should this be used to lift the entire heater, flange lifting points are provided for this purpose. The slotted flameproof bush fitted to the end of the element pocket must be unscrewed using the necessary special tool. By gripping the sheath of the cartridge element, pull it from the pocket. Some force may be required to do this and it can be advantageous to rotate the element back and forth whilst effecting the withdrawal. The replacement element(s) should be checked electrically before fitting. Each element should be pushed into its pocket so as to protrude by the same amount as the others fitted to the heater. There is clearance at the bottom end of the pocket to allow for expansion of the element. Be sure that the terminals are correctly aligned for refitting the busbars. The slotted flameproof bush should now be replaced using Loctite 222 thread locking adhesive on the thread on the end of the pocket. 6
Refit the terminal box and the element flameproof glands before carefully bending the terminal pins back to shape so that the busbars can be refitted. The brass nuts holding the busbars to the element terminations should be tightened to 0.74 foot pounds force (1.0 Nm). All flamepath threads should be lubricated with copper anti-seize compound. Refit the supply cabling to the heater terminal box and reconnect the thermal control devices where fitted. Lubricate the main flameproof box thread with copper based anti-seize compound and screw on the lid (fitted with its o-ring gasket) then lock with the M4 socket head cap screws. These Element Drying Element Drying Procedure Electrically isolate the heater and disconnect the cabling and busbars from the element terminations. Remove the ceramic sealing bead from each end of the element(s) requiring drying out. Completely remove the silicone sealing compound from inside the sheath and around the terminal pin right down to the white powdered magnesium oxide. Ensure that all loose debris is removed from within the element ends. The elements can now be dried out. This should be carried out between 100 C and 200 C for approximately 12 hours or until the resistance to earth is greater than 2 MW. The drying process will evaporate the moisture in the element and drive it along its length and out the ends. Any convenient means of heating can be used but the following is a guide. In Situ Heating Insulate the gap between the element flange and terminal box. This will help prevent the steam condensing in the unheated part of the element. It may even be necessary to provide external heating in this area. IMPORTANT - THIS IS THE ONLY TIME THIS AREA OF THE EQUIPMENT CAN BE INSULATED. IT MUST BE RE- MOVED PRIOR TO RECOMMISSIONING. The heater can be kept bolted to it s mating flange and a low voltage of approximately 50 volts can be applied to a few of the dry elements adjacent to the damp elements. Alternatively, apply the voltage to the damp elements but be careful that the earth leakage circuit breaker does not trip out. This may be obviated by temporarily setting the earth leakage circuit breaker to its maximum setting. If this is done, personnel must be protected and be made aware of any possible danger. Oven Drying Withdraw temperature sensors from heater. Unbolt the heater bundle from its mating flange and dry it out in an oven or similar hot atmosphere. Care should be taken not to damage the element seals if this method of drying is used; the temperature of the heater must not be allowed to exceed 200 C. Element Sealing Important Note: Priming of element ends should be carried out as soon as possible after drying out to avoid ingress of moisture. Chromalox primer is to be applied to the elements ends, i.e. to the internal face of the sheath, the surface of the dead within the sheath and the surface of the insulant (magnesium oxide). A thin film of the primer will give the best seal. Film thickness can be estimated by the color; the thicker the film, the darker the tint. The correct thickness should only give a pale tinge to the surface. Allow the primer to cure at normal temperature and humidity conditions for 1 hour before sealing the elements. Fill the end cavity with Chromalox Silastic sealing compound (part number 113800) to ensure complete potting. Fit sealing bead by pushing down and rotating (to ensure wiping of bead) until it is seated in the top of the element sheath. Fit clamping nut above sealing bead (half nut). Wipe excess sealant from around joint of bead. Allow sealant to cure for a minimum of 24 hours before subjecting to any inspection/running procedures. If any further information is required, please contact your local Chromalox sales office. 7
Limited Warranty: Please refer to the Chromalox limited warranty applicable to this product at http://www.chromalox.com/customer-service/policies/termsofsale.aspx. 1347 HEIL QUAKER BLVD., LAVERGNE, TN 37086 Phone: (615) 793-3900 www.chromalox.com 2012 Chromalox, Inc. 8