Maritime Geothermal TF-45, Инструкция по установке и обслуживанию

Страница: 52 / 89

Page 52 001223MAN-05 1-Jul-2017
OPERATION TROUBLESHOOTING - COOLING MODE
Fault Possible Cause Verification Recommended Action
High Discharge
Pressure
Unit is overcharged.
(Only possible if unit has
been field serviced and incor-
rectly charged.)
High subcooling, low delta T across
water coil.
Remove 1/2lb of refrigerant at a time
and verify that the discharge pressure
reduces. Or remove charge and weigh
back in the amount listed on name-
plate.
High Suction
Pressure
(may appear to
not be pumping)
TXV adjusted too far open. Verify superheat. It should be between
8-12°F (3-6°C). Superheat will be low if
TXV is open too far.
Adjust TXV to obtain 8-12°F (3-6°
C) superheat.
TXV stuck open. Adjusting the TXV does not affect the
superheat or the suction pressure. Low
super heat and discharge pressure.
Adjust the TXV all the way in and out a
few times to loosen it. Replace TXV if
this does not work.
Leaking reversing valve. Reversing valve is the same tempera-
ture on both ends of body, common
suction line is warm, compressor is
running hot.
Replace reversing valve.
Faulty compressor, not
pumping.
Pressures change only slightly from
static values when compressor is start-
ed.
Replace compressor.
Low Suction
Pressure
Low airflow See Fan Troubleshooting section.
Note: low airflow will cause the air
coil to ice up once the suction drops
below 90PSIG .
Correct the problem.
TXV stuck almost closed or
partially blocked by foreign
object.
Adjusting the TXV does not affect the
superheat or the suction pressure.
TXV may be frosting up.
Adjust the TXV all the way in and out a
few times to loosen it. Replace TXV if
this does not work.
Low or no refrigerant charge. Entering air temperature and airflow
are good but suction is low. Check
static refrigeration pressure of the unit
for a very low value. Weigh refrigerant
out and compare to charge listed on
nameplate.
Locate the leak and repair it.
Spray 9, a sniffer, and dye are com-
mon methods of locating a leak.
Compressor
frosting up
See Low Suction
Pressure in this section.
TXV frosting up TXV stuck almost closed or
partially blocked by foreign
object.
Adjusting the TXV does not affect the
superheat or the suction pressure.
Adjust the TXV all the way in and out a
few times to loosen it. Replace TXV if
this does not work.
Random Low
Pressure trip
(does not occur
while there)
Faulty compressor contactor. Points pitted or burned. Contactor
sometimes sticks causing the compres-
sor to run without the fan, tripping the
low pressure control.
Replace contactor.
Intermittent fan. See Fan Troubleshooting section. Correct the problem.
Leaking check valve (located
in the indoor water coil “out”
refrigerant line).
Check valve is cold. Try tapping the valve and switching
from air cool to water heat a few times.
Replace the check valve if the problem
persists.
Faulty NC solenoid valve or
coil.
Verify solenoid by removing it from the
shaft while the unit is running. There
should be an audible click sound if the
solenoid is working. Valve may be cold
if restricted.
Replace solenoid or valve if faulty.
Faulty NC solenoid valve or
coil.
Verify solenoid by removing it from the
shaft while the unit is running. There
should be an audible click sound if the
solenoid is working. Valve may be cold
if restricted.
Replace solenoid or valve if faulty.