Airtek 4087 Walden Avenue, Lancaster, NY 14086 TEL: (716) 685-4040 FAX: (716) 685-1010 E-MAIL: airtek@airtek.com WEB SITE: www.airtek.com
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Another possible determining factor would be
the appearance of the refrigerant sightglass. It
normally appears clear with a color moisture
indicator in the center. If the moisture indicator
is yellow, chances are there is a leak in the
system. The best way to determine a leak is to
contact a refrigeration service house. They
have the technology of a halide torch or
electronic leak detectors.
B) Pressure Switch - If you are low on freon or freon
pressure the low-pressure switch will be showing
electrically open. You can check the low-pressure
switch for continuity to see if the switch is in fact
open. If it is closed you may have a control board
problem. There is a possibility the pressure switch
may be faulty giving a false low-pressure indica-
tion. Again the best way to determine this is to
contact a refrigeration service house. With their
gauges they can check the system pressure and
the settings of the pressure switch. The low-
pressure switch is set to trip at 20 PSI. If you have
an automatic resetting switch it will close again at
50 PSI.
C) Unloader Solenoid Failing to Open
1) You need to first check the coil of the unloader
valve to ensure that it is functioning. The
easiest way to verify if the coil is energized is
to take a screwdriver and touch it to the screw
or post on the top of the coil. If the coil is
energized there will be a magnetic field
pulling the metal to the screw or post. If the
Power Saver Active light is on and there is no
magnetic pull, the coil is not functioning.
2) If you have determined the coil is not function-
ing there are two things you must check.
- Test the coil electrically for continuity to
ensure it is not shorted. If it is shorted
replace the coil.
- If the coil is not shorted you need to check
the K3 relay marked “Unloader”, termi-
nals 9 and 10. There should be a 120V
output from this relay. If there is not
replace the board.
3) If the coil is functioning and the dew point
continues to fall, or the unit shuts down
displaying an “E6”, the unloader solenoid is
defective. The internals or the whole valve
should be replaced.
Remember the unloader must be checked while the unit is
operative and in the unloaded state. The way this is
determined is by the Power Saver Active light being
illuminated.
D) Refrigerant restriction - If there should be a
restriction in the refrigerant system this could
cause a low-pressure situation. The most
common points of restriction are:
1) Faulty suction line solenoid - If the suction line
solenoid (SC/CT1500 and up) were defective
.
or not functioning electronically, this could
cause a restriction. When the Power Saver
Active light is off the suction line solenoid
should be energized and fully open. To verify
this examine the following:
a) You need to first check the coil of the
liquid line valve to ensure that it is
functioning. The easiest way to verify if the
coil is energized is to take a screwdriver
and touch it to the screw or post on the
top of the coil. If the coil is energized there
will be a magnetic field pulling the metal
to the screw or post. If the Power Saver
Active light is off and there is no magnetic
pull; the coil is not functioning.
b) If you have determined the coil is not
functioning there are two things you must
check.
- Test the coil electrically for continuity
to ensure it is not shorted. If it is
shorted replace the coil.
- If the coil is not shorted you need to
check the K2 relay marked “Suction”,
terminals 7 and 8. There should be a
120V output from this relay. If there is
not replace the board.
c) If the coil is functioning and the restriction
seems to remain the valve may be the
problem. The internals or the whole valve
should be replaced. Or the restriction
could be in the expansion valve. This is
rare but possible.
Remember all of this must be checked while the unit is
operative and in the refrigerating state. The way this is
determined is by the Power Saver Active light being off.
2) Service valve. When the dryer is fully opera-
tive, all refrigeration service valves with the
exception of the service valve on the bottom of
the evaporator on models SC/ CT330’s and
up, should be open. If one should be closed,
even partially, this could cause enough of a
restriction to cause low-pressure problems.
3) Faulty expansion valve. This is a very rare
situation however there is means of testing
this theory. Test by applying heat (hair drier) to
TXV sensing bulb located just after the flood
level control for about 30-45 seconds. This
should cause the unit to flood back and lower
the super heat. To check this, take a tempera-
ture reading on the suction accumulator, it
should be extremely cold, if it is not, your
expansion valve is stuck closed or is dirty.
Check to make sure that the capillary tube
from the power head to the sensing bulb is
not severed, this could cause the valve to
close. Your suction accumulator normally
shows a level based on temperature of being
1/3 to 1/2 full. If it is less you may have a
restriction.
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