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Question DetailsAsked on 6/12/2015

Is it possible for 4 lbs of Freon to leak out of ac unit in 24 hrs?

Had a technician out to repair- he cleaned the outside unit and added 4 lbs Freon. Now 24 hours later, I am having the same original problem. No air coming through the vents

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3 Answers


Always need to find the leak. Yes on the 4 lbs, IF it's a large leak,and it should have been easy to find.

No air from vents, indoor coil is likely frozen,turn it off ,can damage the compressor!


Answered 4 years ago by BayAreaAC


You did not say how old this unit was - if quite old, then a 4# loss might have been normal long-term leakage at the seals and compressor, and not actually from a "leak".

I am also going to assume when you say 24 hours later no cold air, that after he refilled it you did have normal cooling for a period of hours.

When BayAreaAC said no air from vents he did not (I presume) mean no air at all - rather, no cold air indicating unit is not cooling, though if the evaporator coil is totally frosted up solid then airflow could be largely restricted.

If you are getting no airflow at all (hot or cold), while it is possible that your evaporator is frosted up so much it is totally blocking airflow, this could be a case of the fan/blower not opearating - blockage at the blower, fan motor failure (perhaps intermittent like a sticky bearing which at times prevents it from starting to turn), control problem, etc. It is possible that the unit being 4# low on gas (assuming it was actually low and not actually overfilled because the tech did not know how to read gas pressures properly) had nothing to do with the failure - may have just been low due to a leak but not related to the immediate problem, though being 4# low would be most of the gas or at least enough to significantly reduce cooling on a normal sized system.

What he said about the unit being frozen up would commonly occur if the evaporator coil is leaking or the return side pressure is low, but if the unit is essentially out of gas - then it would be past that stage because the unit would not be cooling at all.

The lubricant for the compressor runs in the refrigerant tubing, so if the gas is not circulating correctly, not only will the compressor overheat because of the lack of gas passing through it (which removes much of the heat of compression), but it will also eat itself up due to lack of lubrication. Hence the recommendation to power it off till repaired.

As he said, a 4#/day leak should have been pretty easy to tie down - sounds like you got one of the unfortunately all too common lazy HVAC techs who just tops a unit off rather than determining where the leak is when he finds the pressure is low. I would talk to the manager/owner about getting a full refund (including the gas cost) for the first visit, because the tech threw your money away by not checking the system for a leak first. I would also ask that another tech be sent out to dothe job right.

A small leak losing a pound or two a year one might excuse not finding right off, but not one that bleeds off in a day. A normal system should not lose more than a pound every few years or more - many systems go their entire life (10-20 years commonly) without needing addition of gas.

There are actually a couple of reasons it might have bled off in a day (assuming that is what happened) -

1) your initial failure that caused the first callout was a substantial leak, which he did not fix so it bled right off again - probably your presumption

2) your system had bled off over a substantial period of time with pressure dropping progressively - then when he topped it off the leak opened up to a much larger one because of the high pressure on the weakened leak area - a common occurrence with cracked tubing and bad seals/sealant at threaded connections

3) the gas leaked back out because he failed to properly seal off the connections where he hooked on to fill the system - so the leak might have taken much longer to bleed off if he had closed off the connection correctly, and indeed might do so again if it is refilled again

I would be asking them to do a deliberate leak detection test - can be done with a "sniffer" gas detector, or for smaller leaks with a penetrating dye that is injected into the lines BEFORE recharging, which shows a bright color where it leaks.

Of course, the repair after the probably $150-200 range leak detection test could be anuything from zero for tightening a loose connection, on up to a couple of thousand range if the evaporator coil or compressor is shot, in which case (especially for an older unit) total system replacement might be your best bet.

Lots of prior questions and answers addressing the issue of total system replacement versus repair, potential costs and savings, the benefits of increased energy efficiency with newer systems and of a new system warranty, etc can be found in the Home > HVAC link in BRowse Projets, at lower left. Mostly addressed in questions about evaporator replacement, though compressor replacement invokes similar large costs and the issue of how much it is justifiable to spend on repairing an older system.

Answered 3 years ago by LCD


There are many other reasons that will stop air flow. If it leaked that much in 24 hours, the leak should have been obvious or easy to find.

Many legit companys do free second opinions,check around.


Answered 3 years ago by BayAreaAC

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