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Troubleshooting
LV Heat PumpSeries
LV Heat Pump Series
8 733 905 683 (2013/04)
Subject to change without prior notice
No compressor
operation but fan runs
X
X
No fault LED -
contactor energized
Open compressor
overload
Check for supply voltage at the load
side of the contactor. For 3 phase
models check phase rotation and
voltage at all 3 phases.
Poor wiring connections
Look for signs of heat on the wiring
insulation. Check that all wiring
connections are secure and
properly torqued.
Burned out compressor
Does compressor hum when power
is applied? If not check the
resistance of the compressor
windings using the values shown in
the compressor characteristics
chart. Note that the compressor
must be cool (70 deg F) when
checking the windings.
No compressor or fan
operation
X
X
Power LED on
Bad thermostat
connection / faulty
thermostat
Check thermostat and wiring.
Check unit terminal block for 24
VAC between "Y" and "C" and "G"
and "C".
Power LED off
Low or no supply power
Insure that the supply voltage to the
unit is with in the range shown on
the unit data plate.
Faulty control
transformer
Check for 24 VAC between "R" and
"C" on the unit terminal block. For
75 and 100 VA transformers, check
that the transformer circuit breaker
has not tripped. Check low voltage
circuit for overload conditons or
short circuits before replacing the
transformer.
No fan operation - PSC
motor
X
X
Fan relay energized
Faulty motor
check supply voltage from the fan
relay to the motor. Check that all
motor wires are secure. With
power off spin the motor shaft -
noise, resistance or uneven motion
can be signs of motor failure.
Fan relay not
energized
No fan operation signal
Check for 24 VAC across the fan
relay coil. Check all wiring
connections.
Bad fan relay
If the relay coil is energized but the
relay does not pull in, check the
resistance across the relay coil - an
open circuit is an indicator of a
faulty relay.
No fan operation -
constant torque motor
X
X
No fan operation signal
Check for 24 VAC between "G" and
"C". Check all wiring connections.
Loose wiring
Check all wiring connections at
motor and control box.
Faulty motor
Check supply voltage to the motor.
Check that all motor wires are
secure. With power off spin the
motor shaft - noise, resistance or
uneven motion can be signs of
motor failure.
UNIT TROUBLESHOOTING
Problem
Mode
Check
Possible Cause
Action