26
2005 Boreal Geothermal Inc.
www.boreal-geothermal.com
Fault
Possible Cause
Verification
Recommended Action
Compressor not
operating
Open control circuit.
•
Thermostat not calling for heat.
•
High or low pressure limit open.
•
Lock-out relay energized.
•
Control board shows hi or low
pres. permanent lock-out.
Locate open control and determine
cause. Replace faulty control if nec-
essary.
Microcontroller board shows “RED”
high pres. or “GREEN” low pres.
lockout flashing or glowing steadily.
Low refrigerant level.
Compressor repeatedly locks
out on it’s LOW pressure
safety control.
Refrigeration gauges show suction
pressure dipping below 20 psig.
Check refrigerant level.
Compressor “short
cycles”
Intermittent contact in elec-
trical control circuit.
Normal operation except too fre-
quent starting and stopping.
Check anticipator in thermostat.
Make sure setting is for “longest
cycle” or max. amps.
Unit trips off on
“LOW” suction
pressure control.
HEATING
Ambient air too cold.
Measure return air temp. Should be
above 60°F.
Restrict air flow temporarily until
room comes up to temperature.
Faulty low pressure ctrl.
Refrigerant pressure control should
open on drop at approx. 20 psig.
Control should reset automatically.
Heat pump can then be restarted by
resetting the lock-out relay. (Turn
power off then back on) Replace
faulty control if it will not reset.
Low refrigerant charge.
Check return air temp. Normal suc-
tion is 40-60 psig.
Add refrigerant slowly. Check for
possible leaks. Normal charge is 3 to
3.5 lbs. per ton.
Faulty TXV’s
Check individual suctions to verify
that each TXV opening and closing
cycle is approximately the same.
Replace TXV(s) if not operating
properly.
Low or “no” air
conditioning
Refrigerant not returning to
air coil.
Check discharge pressure and gas
temp. Only the gas line(s) that are in
use (indicated by the controller)
should be HOT.
Feel liquid line check valves
Verify refrigerant flow path and
check cooling TXV for proper opea-
tion.
Check temp. difference across coil to
verify refrigerant returning.
Reversing valve “stuck” in
the heating mode.
Unit works well in the heating mode
but there is no loud rushing sound
when unit is quickly switched to
cooling mode.
Check or replace valve solenoid and
if necessary replace entire reversing
valve assembly.
