Ingersoll-Rand 900829, Maintenance Manual

Page: 53 / 142

Refrigeration Service Operations
51
Condenser Blocking Solenoid
Test (Model 30 and 50 Only)
1. Install a gauge manifold set on the engine
driven compressor.
2. Set the thermostat on the lowest setting.
3. Start and run the unit in Cool on the engine
driven compressor until the suction pressure
stabilizes.
4. Check the temperatures of the refrigeration
lines on both sides of the condenser blocking
solenoid by hand. Both sides should be hot. If
not, the condenser blocking solenoid might be
stuck closed.
5. Set the thermostat on the highest setting to
make the unit shift to Heat.
6. The suction pressure should rise and the
discharge pressure should fall as the
condenser blocking solenoid, defrost solenoid,
and liquid injection valve open when the unit
shifts to heat.
7. Let unit run in Heat until the suction and
discharge pressures stabilize.
8. Check the temperatures of the refrigeration
lines on both sides of the condenser blocking
solenoid by hand. Both sides should be about
the same temperature, but should not be hot.
• If both sides are hot, the condenser
blocking solenoid is probably not closing.
Check the continuity of the wiring, the hot
gas heat relay, and the solenoid coil before
assuming the solenoid is faulty.
• If the side of the condenser blocking
solenoid going to the condenser is
significantly colder than the side coming
from the oil separator, the condenser
blocking solenoid is probably leaking.
9. Remove the gauge manifold set when finished
with the test.
Liquid Solenoid Test
(SPECTRUM Only)
1. Install a gauge manifold set on the engine
driven compressor.
2. Set the thermostat for the compartment being
tested to the lowest setting so it will run in
Cool. Set the thermostat for the other
compartment to the highest setting so it will
be in Null.
3. Start and run the unit on the engine driven
compressor until the suction pressure
stabilizes.
4. Check the temperatures of the refrigeration
lines on both sides of the liquid solenoid by
hand. Both sides should be warm. If not, the
liquid solenoid might be stuck closed.
5. Set the thermostat for the compartment being
tested to the highest setting to make that
compartment shift to Null.
6. The suction pressure should fall because the
liquid solenoid closes when the compartment
shifts to Null.
7. Check the temperatures of the refrigeration
lines on both sides of the liquid solenoid by
hand. A temperature difference between the
two sides of the liquid solenoid indicates it is
leaking.
8. Remove the gauge manifold set when finished
with the test.
Suction Bypass Solenoid Test
(SPECTRUM Only)
1. Install a gauge manifold set on the engine
driven compressor.
2. Set the thermostat for the frozen compartment
to the highest setting so it will be in Null. Set
the thermostat for the fresh compartment the
lowest setting so it will run in Cool.
3. Start and run the unit on the engine driven
compressor until the suction pressure
stabilizes.
4. Set the thermostat for the frozen compartment
to the lowest setting to make it shift to Cool.