Sub-Zero Refrigerator Error Code R1: Relay Fault... | appliancefaults.com

Technical Background:

The MCU (Main Control Unit) sends a signal to the fridge compressor relay to energize the compressor. error code r1 indicates the MCU is either not sending the signal correctly, the relay is not responding, or the feedback from the relay is not correct. This involves 120V AC circuits and low voltage DC signals from the MCU.

Symptoms:

The Sub-Zero refrigerator is displaying error code r1. The fridge compartment may not be cooling properly, or the compressor might not be running. You may hear clicking sounds from the relay area, or the display shows the error code repeatedly after resetting the unit.

Possible Causes:

Failed fridge compressor relay
Wiring harness issue to the relay
Defective main control board (MCU)
Compressor overload
Low voltage to the unit
Intermittent power outages affecting the relay operation

Solution:

1

Disconnect power to the Sub-Zero refrigerator at the breaker panel.
2

Locate the fridge compressor relay, typically near the compressor or on the control board.
3

Using a multimeter, check for 120V AC at the relay input when the unit is calling for cooling.
4

Verify the relay output to the compressor using the multimeter. It should also read 120V AC when activated.
5

Inspect the wiring harness connected to the relay for any loose connections, corrosion, or damage.
6

If voltage is present at the input but not the output, replace the relay.
7

If the relay and wiring are good, suspect a faulty main control board (MCU) and consider replacement.

Safety Warning:

Always disconnect power to the refrigerator at the breaker panel before performing any repairs. Lock Out/Tag Out (LOTO) procedures should be followed. High voltage is present in the compressor and relay circuits. Exercise caution when working with electrical components.

Prevention:

Ensure the refrigerator has adequate ventilation to prevent overheating. Check and clean the condenser coils regularly (every 6 months) to improve cooling efficiency. Use a surge protector to protect the unit from power surges.

Expert Tip:

Some Sub-Zero models have a service mode that allows you to manually activate the compressor relay for testing purposes. Refer to the service manual for the specific sequence to enter service mode on your model. It may involve pressing a combination of buttons on the control panel.

Frequently Asked Questions

•What is the correct part number for the fridge compressor relay on my specific Sub-Zero model?

You can find the correct part number by checking the model number label inside the refrigerator and cross-referencing it with the parts list on the Sub-Zero website or a reputable appliance parts supplier.

•How do I test the compressor windings to rule out a compressor issue?

Use a multimeter to measure the resistance between each of the compressor terminals. A short or open winding indicates a compressor failure. Also, check for a short to ground by measuring the resistance between each terminal and the compressor housing.

•What voltage should I expect to see on the control board pins that activate the relay?

Typically, the signal voltage from the control board to activate the relay is a low voltage DC signal, usually 5V DC or 12V DC. Refer to the wiring diagram for your specific model for the exact voltage.

Sub-Zero Refrigerator Error Code R1: Relay Fault Troubleshooting Guide

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the correct part number for the fridge compressor relay on my specific Sub-Zero model?

•How do I test the compressor windings to rule out a compressor issue?

•What voltage should I expect to see on the control board pins that activate the relay?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: