American Dream Ultra Performance Geothermal Copper Series, Installation And Service Manual

Page: 34 / 60

Page 34 000744MAN-02 25 MAY 2009
AIR OPERATION TROUBLESHOOTING - HEATING MODE
Fault Possible Cause Verification Recommended Action
High Discharge
Pressure Air Flow. See Fan Troubleshooting section. Correct the problem.
Heating TXV’s adjusted
too far closed. Verify superheat. It should be be-
tween 8-14°F (3-8°C). Superheat will
be high if TXV’s are closed too far. Adjust TXV to obtain 8-14°F
(3-8°C) superheat.
One or more heating
TXV’s stuck (too far
closed). 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.
Faulty Normally Open so-
lenoid valve (stuck
closed). A click can be heard when the coil is
energized but the valve is cold in-
stead of warm. Replace NO valve.
Filter-drier plugged.
Feel each end of the filter- drier, it
should be the same temperature. If
there is a temperature difference then
it is plugged. Also causes low suc-
tion pressure. Replace filter-drier.
Unit is overcharged. High sub-cooling, low delta T across
air coil. Remove 1/2lb of refrigerant at a
time and verify that the discharge
pressure reduces.
Surging
Discharge
Pressure
Heating TXV’s adjusted
too far closed. Verify superheat. It should be be-
tween 8-14°F (3-8°C). Superheat will
be high if TXV is closed too far. Adjust TXV to obtain 8-14°F
(3-8°C) superheat.
Low Suction
Pressure Heating TXV’s adjusted
too far closed. Adjusting the TXV does not affect the
superheat or the suction pressure.
TXV may be frosting up. Adjust TXV to obtain 8-14°F
(3-8°C) superheat.
One or more heating
TXV’s stuck (too far
closed). 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.
Faulty Normally Open so-
lenoid valve (stuck
closed).
** May actually draw a
vacuum.** A click can be heard when the coil is
energized but the valve is cold in-
stead of warm. Replace NO valve.
Filter-drier plugged.
Feel each end of the filter- drier, it
should be the same temperature. If
there is a temperature difference then
it is plugged. Also causes low suc-
tion pressure. Replace filter-drier.
Low refrigerant charge. Check static refrigeration pressure of
the unit for a very low value. Low
discharge pressure when running. Locate the leak and repair it.
Spray nine, a sniffer and dye are
common methods of locating a
leak.
Faulty compressor, not
pumping. Pressures change only slightly from
static values when compressor is
started. Replace compressor.