40
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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
Fault Finding: Chart 10
Replace the compressor.
Replace the fan.
YES
Replace the element.
Replace the thermostat.
Check for pinched or damaged wiring
touching the heater jacket.
YES
NO
YES
NO
Is any reading below
1 megaohm? (1 M
Ω)
Electrical Insulation Testing
YES
Disconnect the compressor wiring
from the compressor and megger
between each terminal and earth.
Disconnect the evaporator fan plug
from the controller and megger
between each wire and earth.
Is any reading below
1 megaohm? (1 M
Ω)
Is any reading below
1 megaohm? (1 M
Ω)
Disconnect the wiring to the element
from the thermostat and megger
between each wire and earth.
Disconnect the remaining wiring from
the thermostat and megger between
each terminal of the thermostat and
earth.
Disconnect the circulator wiring from
the circulator and megger between
each terminal and earth.
Is any reading below
1 megaohm? (1 M
Ω)
NO
Replace the circulator.
YES
Reconnect the wiring, then disconnect
the compressor plug from the
controller and megger between each
wire and earth.
Is any reading below
1 megaohm? (1 M
Ω)
Replace the compressor wiring.
NO
YES
Reconnect the wiring, then disconnect
the circulator plug from the controller
and megger between each wire and
earth.
Is any reading below
1 megaohm? (1 M
Ω)
Replace the circulator wiring.
YES
NO
NO
Is any reading below
1 megaohm? (1 M
Ω)
Disconnect the mains power plug from
the controller and megger between
each terminal of the controller‟s mains
jack and earth.
Is any reading below
1 megaohm? (1 M
Ω)
Replace the controller.
YES
Reconnect the mains power plug to
the controller, then disconnect the
heat pump mains wiring from the
thermostat and megger between each
wire and earth.
NO
NO
Is any reading below
1 megaohm? (1 M
Ω)
Replace the storage tank.
YES
NO
10
