When a legacy UC-24 undercounter, such as the UC-24R or UC-24BG, starts a defrost cycle, the control expects to see voltage come back on the gray/white wire. Code 22 means that feedback was missing at defrost…
When a legacy UC-24 undercounter, such as the UC-24R or UC-24BG, starts a defrost cycle, the control expects to see voltage come back on the gray/white wire. Code 22 means that feedback was missing at defrost start. In practice the control cannot confirm the defrost circuit is working. A 600 or 700 Series refrigerator showing 22 follows another chart, which is why the model matters here. If the cause is real, frost will slowly build on the coil and cooling will weaken over days or weeks.
1. Note how long the code has been showing. 2. Look for frost building on the rear wall. 3. Keep the door closed and do not overload the cabinet. 4. Reset power once at the breaker after one minute off. 5. If 22 comes back, schedule service before frost blocks airflow.
On the UC-24 it carries voltage back to the control when defrost begins, confirming the circuit is complete. Code 22 means the control did not see that return voltage.
Usually not. It keeps cooling, but if defrost is not happening, frost builds slowly on the coil. Over time airflow drops and the cabinet warms, so it is better fixed early.
It depends on where the circuit is open. We test the wire, heater and terminator, then give you a written price before work starts. A loose terminal costs far less than a heater.
A technician diagnoses it on site and gives you the price in writing before any work starts.
