Thorne & Derrick EXHeat RFA Series, Installation, Operation And Maintenance Instructions

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6.6.3 Annually
a. Carry out all 3 monthly and 6 monthly checks as above.
b. Check for element failure or low insulation resistance.
6.7 Only Exheat Ltd or its approved agent to carry out rod type element replacement in flameproof heaters otherwise
the certification will be invalidated.
6.8 If heaters are being left unused for a period greater than 3 months, carry out 6 monthly maintenance before
energizing.
6.9 IR Low Insulation / Earth Leakage Prevention
6.9.1 Heaters must be handled carefully and stored in a clean and dry environment
.
6.9.2 The storage period should not exceed 12 months.
6.9.3 The silica gel bags must remain within the terminal box and replaced as required.
6.9.4 The cable entries must be plugged at all times.
6.9.5 The terminal box lid must be replaced immediately after any installation work has been carried out.
6.10 Removal and Replacement of Ceramic Core Type Heating Elements (core-type heaters only)
6.10.1 Replacement of this type of heating element may be carried out without removing the heater assembly from its
tank or vessel and without draining it down.
6.10.2 Isolate the electrical supply and remove the cover (after releasing locking grub screw using a 3mm A/F hex key –
flameproof heaters only).
6.10.3 Disconnect electrical connections and remove cables to heater (single core flameproof heaters only).
6.10.4 Slacken base locking grub screw then unscrew and remove terminal box body (single core flameproof heaters
only).
6.10.5 Release clamps securing heating element.
6.10.6 Carefully withdraw heating element from its tube.
6.10.7 Check element tube is clean and dry internally.
6.10.8 Carefully fit replacement healing element through a new sealing gasket and into tube whilst preventing it from
bending and protecting it from mechanical shock.
6.10.9 Re-assemble heater and re-connect wiring (reverse of 6.9.2 to 6.9.5 above).
6.10.10 Carry out 6 monthly checks as above.