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TROUBLESHOOTING
(CONT.)
Insufficient
cooling or heahng
UPM board
trouble
shooting
Umt undersized
Loss of conditioned
aLrby leakage
A_rflow
Refngerant charge
Compressor
Reversing Valve
Operating
pressures
TXV
Moisture,
noncondensables
Recalculate heahng and or coohng loads If excesswe, possEbly
adding msulahon and shading will rectify the problem
Check for leaks in duct work or mtroduchon of ambLent air
through doors or wmdows
Lack of adequate aLr flow or improper distnbuhon of aLr
Replace d_rty filter
Low refrigerant charge causing meff_cLentoperahon,
Check for defectwe compressor
If dLscharge is too low and
suction pressure Lstoo hEgh, compressor _snot pumping
properly, Replace compressor
Defectwe reversing valve creating bypass of refrigerant from
dLscharge of suction side of compressor
Replace reversing
valve
Compare umt operahon pressures to the pressure/temperature
chart for the umt
Check T XV for possible restnchon or defect Replace ff
necessary
The refrigerant system may be contaminated wEth mo+sture or
noncondenstbles
ReclaLm refrigerant, replace filter dryen
evacuate the refrigerant system, and recharge w_th factory
recommended
charge
Compressor will
not run, no fault
bhnk code
IS G{eef/
Po_; et LED
hgllt Of/ and
no Red
BIm k Cocle 9
iS tFlete
po_%et to
tile
Y Call
_
iOyi 9
_r
Clleck
all
po'¢ et S LII)I)IleS
Clqeck all
safety s_, _tches
Is tllete
24 V
[)OVvet
ff 01_1
_,
C to CC")
Clleck
tiler
rllostat
E_
settlf/gs
and
COrlflgLItatlof/s
for
Ileat
[)LimpS,
alld
UPM Board
IS Good
t
Check
for
Red
Bhnk Code
If Red Bhnk
Code
IS not
present,
tel)lace
UPM Board
16
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