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

Page: 3 / 8

3
4.0 EARTH CONNECTION
4.1 WARNING – these heaters MUST BE EARTHED.
4.2 An internal earth connection is provided inside the terminal box.
4.3 An external earth connection (flameproof heaters only) is located adjacent to one of the terminal box cable entries.
5.0 OPERATION
5.1 Ensure that the active section of all the heating elements are fully immersed in the fluid to be heated at all times
whilst energized.
5.2 Heat is transferred by means of electric heating elements.
5.3 Control of the heater is facilitated by thermostats, thermocouples or RTD’s and reference should be made to the
wiring diagram (inside the cover – non-flameproof heaters only) to ensure that these are correctly connected and
set prior to energising the heater.
5.4 Where a manual reset thermostat or cut-out is installed, the terminal box cover will have to be removed to enable
a reset to be carried out.
6.0 MAINTENANCE
6.1 All prevailing site safety regulations shall be adhered to at all times.
6.2 Any damage or faults should be notified to Exheat Limited immediately
6.3 Equipment must be fully isolated from the electrical supply before and whilst any work is being carried out.
6.4 Before and whilst any maintenance activity is carried out, it must be ensured that there are no hazardous gases
present.
6.5 Replacement of core type heating elements may be carried out without removing the heater by disconnecting the
element and withdrawing it from its tube –
CAUTION : hazardous area core heaters must NOT be energised with
any core elements missing from their respective tubes.
6.6 For flameproof heaters reference should be made to IEC / EN60079-17 (especially table 1) in addition to the
following recommendations.
6.7 Any replacement parts required must be obtained directly from Exheat. The use of any other parts will void any
certification and warranty.
6.6.1 3 Monthly
a. Generally inspect the equipment for external damage or leaks.
6.6.2 6 Monthly
a. Isolate the electrical supply and remove the cover (after releasing locking grub screw using a 3mm A/F
hex key – flameproof heaters only).
b. Check that the terminal box is clean and dry internally.
c. Check that the electrical terminals are intact and secure.
d. Check that the heating element insulation resistance is at least 2 megohm.
e. Check the continuity of all heating elements.
f. Refit cover with new gasket or ‘o’ ring if required (and re-tighten locking grub screw – flameproof
heaters only).
g. Check that earth continuity is maintained between all exposed conductive material and main structure.