Repair or Replace · situation 9 of 10
Topping Up the Refrigerant Versus Finding the Leak
A Sub-Zero short of refrigerant has lost it from a closed loop, so the real choice is between a top-up that buys time and a repair that finds the leak.
Sub-Zero Repair Sammamish · (425) 610-8986 · $89 service call, credited
- Compiled by
- Marta Fennimore
- Holds
- EPA 608 certified
- Dated
- Years at the work
- 12
Refrigerant is not used up, so a low charge means a leak
The sealed system is closed: compressor, condenser, drier, evaporator and the tubing that joins them. The refrigerant inside circulates round that loop again and again; it does not burn off or wear out the way oil does in an engine.
So if a technician finds the charge low, it left through a gap somewhere in the loop: a joint, a tube rubbed thin, a pinhole in a coil. Where it went matters more than how much is missing, because the answer decides whether the repair is small or large.
Sub-Zero Repair Sammamish · (425) 610-8986
A top-up buys time and leaves the cause where it was
Topping up means connecting gauges and adding refrigerant until the unit cools again. It is quicker than a leak repair and costs less on the day.
What it does not do is stop the loss. From the moment the gauges come off, the unit is heading back to the same point, and how fast depends on the size of the leak, which a top-up never measures. It can also skip steps Sub-Zero sets for sealed-system work: the 600-3 service manual requires a new high-side filter-drier whenever the sealed system is serviced.
Sub-Zero Repair Sammamish · (425) 610-8986
Column one
If you repair
- The work
Locate the leak, repair or replace the leaking section, fit a new filter-drier, evacuate the loop and charge it to the unit's specified amount.
- What it comes to
-
$1,460–$3,380 plateau range for compressor or sealed-system repair
The $89 visit is credited against it once you say yes.
- Still unknown
Exactly where the leak is until it has been traced, and whether other joints of the same age hold for years to come.
- This column wins when
The leak sits in a reachable joint or line, the cabinet and doors are sound, and replacing the built-in would mean reworking its opening.
Sub-Zero Repair Sammamish · (425) 610-8986
Column two
If you replace
- The work
Stop the top-up cycle by replacing the unit outright, which ends the leak question without ever answering it and starts a new sealed system from zero.
- What it comes to
-
$11,550–$20,400 reference figure on the plateau for a comparable built-in replacement, before installation and cabinetry work
- Still unknown
Whether the leak was ever large enough to justify that. Only a proper search puts a size on the loss, and a top-up never measures one.
- This column wins when
The leak turns out to be in a part that takes most of the sealed-system band, or the cabinet is already worn in other places.
Sub-Zero Repair Sammamish · (425) 610-8986
Finding the leak is the repair that closes the question
A full repair locates the leak, mends or replaces the leaking section, fits a new filter-drier, pulls the loop into a deep vacuum and charges it with the amount the unit is specified for. It takes longer and costs more than a top-up.
It can also turn up a leak in a part that is a large job in its own right. That is the point where repair and replacement get compared on real figures rather than hopes, which is what the two columns on this page lay out.
Sub-Zero Repair Sammamish · (425) 610-8986
Step by step
Questions to ask before approving a top-up
- Ask whether a leak was found, and where
Adding refrigerant without looking for the loss treats the symptom alone. Ask what search was made for the leak and what it showed.
- Ask whether the filter-drier will be changed
Sub-Zero's 600-3 service manual calls for a new high-side filter-drier whenever the sealed system is serviced. Ask whether it is part of this quote.
- Ask whether the loop is evacuated first
A deep vacuum before charging draws out air and moisture. Ask whether the job includes it, or whether refrigerant simply goes on top of what is left.
- Ask for the refrigerant type and amount
Both belong on the invoice. The amount added is the clearest record of how much was lost, and it matters if the unit warms again.
- Ask how the result will be checked
The unit should be pulling down toward its setting before the visit ends, and you should know what temperature to expect over the following 24 hours.
That is where an owner's part ends. Panels, wiring and refrigerant are a technician's work — Sub-Zero Repair Sammamish, (425) 610-8986.
