Sub-Zero Designer Code 15-C-00: Condenser circuit relay open

What 15-C-00 means

On current Sub-Zero Designer units such as the DET3050CI and DEC3050R, 15-C-00 means the control-board relay that switches the condenser circuit reads open. The control has commanded that circuit on, but sees no closed path through the relay. The condenser circuit helps carry heat out of the unit, so if it does not switch on, heat can build in the machine compartment and cooling may weaken across zones. Owners might feel extra heat at the kickplate or notice zones warming.

Common causes of 15-C-00

Relay on the control board not closing
Open wiring or loose plug on the condenser circuit
Control board output not switching

✓ One safe check you can try

1) Make sure the kickplate grille is not blocked by trim, rugs or stored items. 2) Feel for unusual heat coming from the grille area. 3) Turn power off at the breaker for a minute, then restore it. 4) Check each zone with a thermometer over the next day. 5) Call us if the code returns.

! Why to stop there

Relay checks involve live voltage.
The machine compartment has high-voltage wiring.
Board repairs need the correct part.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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15-C-0015-C-00 questions

What does the condenser circuit relay do?

It is the control-board relay that switches the condenser circuit, which carries heat out of the unit. When it reads open, that circuit may not run, and heat builds in the machine compartment.

Is 15-C-00 urgent?

It can be. With heat trapped below, cooling may weaken across every zone at once, so booking service within a day or two protects your food.

How is it repaired?

We test the relay output on the control, the wiring and the connections, then repair or replace the part that failed. You see the written price before we start.