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This document is stored and maintained electronically by
Service. All printed copies are deemed uncontrolled.
TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
General Fault Diagnosis
General Fault Diagnosis
Is the complaint for no hot water?
Is the complaint for insufficient
hot water?
Is the complaint for a leaking
water heater?
Is the complaint for a noisy water
heater?
YES
YES
YES
Is the red LED displaying
a Fault Code?
YES
Are either of the LEDs
illuminated?
Replace the LED panel and continue
with fault diagnosis.
Is the complaint related to the
green or red LED not illuminating,
displaying a random sequence or
displaying something not listed in
this manual?
Unit in Standby Mode.
Is the tank sensor working?
TEST 1
If the tank sensor has failed, replace
the tank sensor.
If the tank sensor is OK, replace the
controller.
YES
Is the green LED on solid?
Is there any evidence of broken
or fractured refrigerant piping, in
particular the suction line and / or
the TX capillary tube?
The heat pump module (not the
storage tank) MUST be immediately
decommissioned and replaced.
Is the TX capillary tube the ONLY
broken pipe?
YES
NO
YES
Replace the TX valve.
Is the green LED displaying
1 short flash?
NO
Wait for the start delay to elapse and /
or the compressor to cool, then
continue with fault diagnosis.
NO
NO
YES
Is the complaint for the water
heater operating in Element
Mode?
4
4
7
8
10
NO
NO
1
NO
YES
YES
NO
2
YES
Is the green LED displaying
1 long flash?
NO
3
YES
9
NO
YES
NO
NO
Blowing fuse / circuit breaker
