
Troubleshooting
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37
QV Series Heat Pumps
8733829041 (2021/07)
QV Series Heat Pumps
Subject to change without prior notice
NO
COMPRESSOR
OPERATION
BUT FAN RUNS
(CONTINUED)
X
Is the Fault
LED
blinking two
(2) times?
Low pressure
fault—No or
low air flow
Check water valves and/or pumps for
proper operation. Check for water coil
blockage.
75 Unit
Check for proper flow rate and water
temperature, but low-water-side temp
rise in cooling.
Low pressure
fault—Low
refrigerant
Check refrigerant pressure with a
gauge set.
X
Is the Fault
LED
blinking three
(3) times?
Freeze fault,
water coil—
No or low
water flow
Check water valves and/or pumps for
proper operation. Check for water coil
blockage.
Freeze fault -
low
water
temperature
Check water temperature - is it
below 40° F entering? If heat pump
is connected to a closed loop with
antifreeze check that the “FREEZE 1"
resistor on the UPM board has been
cut to set the unit to antifreeze mode
(see UPM features on page #27).
Freeze fault -
low
refrigerant
Check refrigerant pressure with a
gauge set.
X
Is the Fault
LED
blinking four
(4) times?
Condensate
fault—Poor
drainage
Check condensate pan for high water
level. Check drain line for blockages,
double trapping or inadequate
trapping.
Condensate
fault—blocked
return air
Check air filter and return air
duct work for blockage. Check that
there is adequate space
between the return air opening and
walls or other obstructions on free
return applications.
Unit Troubleshooting
Problem
Mode
Check
Possible
Cause
Action
Cooling
Heating