Electrical Insulation Testing - Rheem 55027500 Service Instructions Manual

Electrical Insulation Testing

There are three basic test procedures that should be carried out when the operation and
function of a heat pump water heater's electrical system is in doubt.
Personal Protective Equipment should be worn when conducting step 1 of
this procedure to reduce the risk of electric shock. Refer to Rheem safety
procedure on electrical testing.
Insulation resistance of the water heater Neutral Circuit. (Reading not to be below 1
Mega ohm).
1. Isolate power to the water heater at the isolation switch. Confirm with multi-
meter across Active and Neutral at the terminal block that voltage is not present.
2. Once satisfied, disconnect the active and neutral wires from the water heater terminal
block.
3. Connect megger leads to the neutral of the water heater wiring and earth.
4. Operate megger. A reading above 1 Mega ohm should be obtained.
5. If a reading below 1 Mega ohm is indicated, all component parts will need to be
individually tested to locate the fault. Refer to flow diagram 6.
Insulation resistance of the water heater Active Circuit. (Reading not to be below 1
mega-ohm).
6. Connect megger leads to the active of the water heater wiring and earth.
7. Operate megger. A reading above 1 Mega ohm should be obtained.
8. If a reading below 1 Mega ohm is indicated, all component parts will need to be
individually tested to locate the fault. Refer to flow diagram 6.
To check "Continuity" of the heat pump electrical circuit.
9. Set megger to resistance scale or multimeter to x1 resistance scale.
10. In heat pump mode the resistance should be approximately 3.6 ohms. In boost mode
the resistance should be between 15 and 17 ohms. If a reading outside these
resistances is measured all electrical component parts will need to be individually
tested to locate the fault.
11. Reconnect active cable to 'A' terminal and neutral cable to 'N' terminal at heater
terminal block.
12. Replace fuse. Note: If continuing with any diagnostic procedures do not replace
the fuse.
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
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