- “Runs all day, temperatures still fine”
- “Warmer kitchen than it used to be”
- “Higher electricity bill with no other change”
Symptom
Sub-Zero unit running constantly
A compressor that runs without stopping, or cycles far more than it used to, while temperatures still look about right. Usually the earliest warning sign this equipment gives.
- From $95 diagnostic, credited to the repair
- 59 cities and neighborhoods covered
- OEM parts available on order
- In writing the price, before anything is opened
Five ordinary causes
What this usually turns out to be
Cheapest and commonest first, which is also the order we check them in. They sit hundreds of dollars apart, and only the unit settles which one is yours.
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A condenser that cannot shed heat
Dust inland, salt corrosion near the water. Look through the grille — this is the cause behind more continuous running than everything else here put together.
Condenser fan and coil service from $280 -
A fan out of range
Airflow across the coil has dropped, so the system runs longer to do the same work. It often shows as a change in sound before anything else.
Condenser fan and coil service from $280 -
Door seals letting warm air in
Continuously, which is why the unit never gets to stop. Check the seal along its whole length rather than at the handle.
Door gasket replacement from $220 -
The room itself
A unit in a hot kitchen or an outdoor enclosure in August is being asked for more than it was designed to give. Worth knowing before anything is replaced.
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Weeks of it, unnoticed
A unit that never cycles off is holding temperature by running continuously, and that is the state in which compressors age fastest. Catching it here is the difference between a condenser service and a sealed system repair.
Sealed system repair from $1,200
In five minutes
Before you call anybody
None of it needs tools, and all of it makes the visit shorter.
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01
Look at the condenser through the grille
Dust inland, salt corrosion near the water. This is behind more continuous running than everything else put together, and you can see it without tools.
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02
Check whether the room itself is hotter
A unit in a hot kitchen or an outdoor enclosure in August is being asked for more than it was built to give. Worth knowing before anything is replaced.
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03
Check the seals along their whole length
Not just at the handle. A door letting warm air in continuously is why the unit never gets to stop.
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04
Then book the visit
Say how long it has been running without cycling off. Weeks of it is the difference between a condenser service and a sealed system repair, and that is why it is worth saying.
How it shows up
What people describe when they call
A shortcut
Narrow it down before anybody arrives
A description of the behaviour leaves a few possible causes. A code names the subsystem before anybody opens anything, which is why it is worth photographing before it clears.
If the display is showing something
Photograph it before it clears — codes do not wait. Search the full code list
In more detail
About Sub-Zero unit running constantly
The fastest diagnosis is the code
A fan or load code here saves a lot of measuring. If the display has one, it usually names the reason the unit cannot stop running.
Why it matters before temperatures change
A unit that never cycles off is working at the limit of what it can do. It is holding temperature today; it is doing so by running continuously, and that is the state in which compressors age fastest. Catching it here is the difference between a condenser service and a sealed system repair.
What is usually behind it
- A condenser that cannot shed heat — dust inland, salt corrosion near the water
- A fan out of range, so airflow across the coil has dropped
- Door seals letting warm air in continuously
- Ambient heat: a unit in a hot kitchen or an outdoor enclosure in August
This article is based on:
- Official manufacturer documentation
- Internal repair procedures
- Technician repair history
- Company quality standards
Before you book
Questions about Sub-Zero unit running constantly
It holds temperature, so is it fine?
It is holding by running continuously, which is the state in which compressors age fastest. Catching it here is the difference between a condenser service and a sealed system repair.
Could it be the weather?
Partly — ambient heat matters, especially on an outdoor unit in August. But a unit that has run continuously for weeks is worth looking at regardless.
What do you check first?
The condenser through the grille, then whether the fan is running in range, then the door seals.
Where we do it
Across Miami-Dade, Broward, and Palm Beach
Same terms everywhere we go: an on-site diagnostic first, the price agreed in writing, and the exact figure confirmed once we have seen the unit.
Neighborhoods people ask for by name