Trebor Quantum Series Di Water Heater - Manual (Page 34)

PAGE 34 QUANTUM DI HEATER OPERATION / MAINTENANCE MANUAL
7 MAINTENANCE
7.1 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 lower element for consistent
temperature control.
7.1.a Heater Element Check
If the control screen indicates a check heater element status bar, check
the heater diagnostic display for information about heater module status.
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:
1. Shut off power to the system.
2. Lockout and Tagout power to heater.
3. Switch off the element circuit breakers in the control enclosure.
4. Check for continuity between the two screw terminals on the left of
the breaker for each pair of element circuit breakers.
5. If no continuity exists, replace the suspect heater modules; see
Section 7.1.b Heater Replacement.
6. If there is continuity, then the heater element is OK. Refer to the
Troubleshooting Section of this manual for other possible causes.
7.1.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 2.5 for Lockout/Tagout
procedures).
Drain system (see Section 7.1.e, Draining the System).
Remove the rear panel of the enclosure to access heater modules.
Disconnect the electrical connector to the failed module.
Remove process thermocouple by unthreading thermocouple fitting
from top header of the module. It should be hand tight. A wrench may
be required to loosen.