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DEFROST HEATER TEST PROCEDURES
Measurement Procedure
connections from the defrost
terminator to the defrost heater.
5 If the voltage is not good, measure
the voltage from the control board.
Control board voltage 1 Activate the defrost system in
manual component activation mode.
2 Back pin P15-8, the blue wire, and in
VAC, measure the voltage from
P15-8 to ground.
3 If the voltage is approximately 230
VAC, the voltage to the defrost
terminator is good.
4 If the voltage is good, turn off the
power to the unit, and check the
continuity of the blue wire from the
control board to the unit harness
connector, across the unit harness
connector, and from the cabinet side
of the unit harness to the defrost
terminator connector.
5 If the voltage is not good, turn off the
power to the unit and disconnect
P15-8, and measure the continuity
across the connector.
6 If the continuity across the P15-8
connector is good, replace the
control board.
BI-36UFDID and BI-42UFDID Drain Trough Heater Test Procedure
This test procedure is for the BI-36UFDID and BI-42UFDID
models (including ICB) above serial number 4380000.
Confirm the drain trough heater is working by activating the
defrost system in manual component activation mode. See the
instructions in the Controls and Operation section of the service
manual. Remove the freezer air duct to confirm that the drain
trough heater is operating.
To measure the resistance of the drain trough heater:
1 Turn the power off to the unit.
2 Disconnect the drain trough heater harness from the defrost
harness.
3 Measure the resistance between the drain trough heater
terminals. Compare the results with the Technical Data
table.
4 If the results are good, check the continuity across the drain
trough heater connector.
5 If the results are bad, replace the drain trough heater.
SEALED SYSTEM
Sealed System Troubleshooting
Enter the sealed system to check pressures only if the Error
Code Troubleshooting Guide and General Troubleshooting
Guide do not pinpoint the cause of the temperature problem.
▪ Always use solder-on process valves when entering the
sealed system. Do NOT use bolt-on process valves as they
are prone to leak.
▪ When servicing the sealed system, always replace the high
side filter drier.
▪ System pressures are listed in the Technical Data section of
the service manual.
▪ Pressures listed are for reference only; actual pressure
readings may vary because of ambient temperatures,
temperature setpoints, food load, food temperature,
condenser cleanliness, or gauge calibration.
Non-Functional, Inefficient, or Noisy Compressor
1 Always evacuate R600a refrigerant to the outdoors.
2 Use nitrogen for back-flushing the system.
3 Remove the compressor.
4 Replace the high-side filter drier.
5 Recharge the system with virgin R600a refrigerant.
High Side Leak
1 Always evacuate R600a refrigerant to the outdoors.
2 Use nitrogen for back-flushing the system.
3 Repair any leaks at the solder joint or replace the defective
component.
4 Replace the high-side filter drier.
5 Bump or tap the compressor to help release residual
refrigerant from the oil in the compressor.
6 Recharge the system with virgin R600a refrigerant.
Low Side Leak
1 Always evacuate R600a refrigerant to the outdoors.
2 Use nitrogen for back-flushing the system.
3 Repair any leaks at the solder joint or replace the defective
component.
4 If all refrigerant escapes and the system is in a vacuum,
replace the compressor.
5 Replace the high-side filter drier.
ICBBI-42UFDID
Troubleshooting
BUILT-IN DEFROST HEATER TEST PROCEDURE (continued)
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