Trebor Q-Series Di Water Heater - Manual (Page 25)

Q-SERIES DI HEATER OPERATION / MAINTENANCE MANUAL PAGE 25
8 MAINTENANCE
8.1 REPAIR INSTRUCTIONS
Heater modules have a finite life. Spare heating modules should be on
hand in case of a failure.
NOTE: If top element fails then switch off circuit breaker for lower
element to maintain consistent temperature control.
8.1.a Heater Element Check
If the heater is having difficulty maintaining set point, visually inspect the
main and auxiliary circuit breakers. Then check the corresponding
element isolation circuit breaker to see if it has tripped.
Check the continuity of the heating elements as follows:
Turn power off to system (see Section 2.3 for Lockout/Tagout
procedures).
Switch off the element circuit breakers in the control enclosure.
Check for continuity between the two screw terminals on the left of
the breaker for each pair of element circuit breakers.
If no continuity exists, replace the suspect heater modules; see
Section 8.1.b Heater Replacement.
If there is continuity, then the heater element is OK. Refer to the
Troubleshooting Section of this manual for other possible causes.
8.1.b Heater Replacement
The heater modules have been designed for quick replacement to
minimize downtime and field service requirements. To replace a heater
module, follow these procedures:
Turn power off to system (see Section 2.3 for Lockout/Tagout
procedures).
Drain system (see Section 8.1.d, Draining the System).
Remove the side panel of the enclosure to access heater modules.
Disconnect the electrical connector to the failed module.
Remove steel band clamps connecting heater module to cabinet, but
do not remove clamps used to connect the electrical box to the
module housing
Loosen fluid inlet and outlet fittings on module.