EC 40 says the freezer compressor ran longer than the control expects. That is a statement about cold leaving the box, not a verdict on the compressor itself.
- What the control is watching
- Nothing more than how long the freezer compressor runs, measured against how long the control reckons it needs.
- What makes it register
- Run time that keeps overshooting, for whatever reason — heat getting in, cold not circulating, or a sensor that never reports arrival.
- Can you keep using it
- Usually yes, and most cabinets carrying this code are still cold. What is being spent in the meantime is the compressor's working life.
The name on this code is the most misleading thing about it. It reports a duration, not a diagnosis, and the documented order of tests reaches the sealed system only at the tenth step, after the condenser, the fans, the door, the thermistor and the light switch.
That last one catches people. A switch that fails to cut the interior lights when the door shuts leaves a small heater burning inside a very well insulated box, and the compressor spends the night answering it.
A warm kitchen supplies the rest, which matters at the Encino end of this sector: Sub-Zero says plainly that higher room temperatures make the compressors run longer.
What we usually find
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A condenser furred over with dust and lint, and a machine compartment that is hot to stand beside
Heat with nowhere to go. It is the first item on Sub-Zero's own list for a unit running excessively, and the usual answer after a dusty summer.
Quoted after the diagnosis
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A compressor that never stops through the afternoon and settles down again overnight
A condenser or evaporator fan slowed, seized or fouled by something in its path. The cabinet copes while the kitchen is cool and loses ground once it is not.
Evaporator or condenser fan motor $330–$750
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Long runs on a freezer that is actually reading colder than it has been set for
The freezer compartment thermistor reading high, so the control keeps calling for cold that has already arrived. It is measured against a published resistance.
Defrost heater, thermostat or sensor $280–$640
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This code stored alongside one of the defrost codes from the same table
Frost on the evaporator blocking the air path. The defrost fault is the cause and the run time is the consequence, so the defrost fault is what gets put right.
Defrost heater, thermostat or sensor $280–$640
Which of these it is gets settled at the visit, before a part is ordered — Sub-Zero Repair Pro Los Angeles, (310) 844-1973.
- Written by
- Yuki Tanabe
- Role
- Refrigeration technician — controls and sensors
- In the trade
- 18 years in the trade
