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Question DetailsAsked on 6/17/2013

Is it possible to fill too much refrigerant into an AC system?

Is it possible for an HVAC technician to overfill an AC system with too much refrigerant (R-22)? For example, if the system needs 2 pounds, is it possible for the technician to force in say 3 or 4 pounds? If so, can this damage the AC system or cause it to malfunction and stop cooling?

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5 Answers


Yes , it can be done, but is usually the result of an under or untrained technician. Also low air flow will often cause somone to do this.

Damage can result.

Why do you ask???


Answered 7 years ago by BayAreaAC


Yes, you can overfill an A/C system. It will cause damage if it is excessively overcharged which it sounds like it may be. Depending on which brand it is it should trip off on high pressure. Hopefully saving the system from too much damage. Not sure why anyone would over charge a system by two pounds but I know it happens. Call someone else hopefully more knowledgeable to remove all the refrigerant and install the correct amount for the system. It kinda xxxx you got to pay for possibly two extra pounds of a refrigerant that is not getting any less expensive lately.


Answered 7 years ago by ylekiyot


Thanks for the two answers. I asked the question because my AC system information sheet says it has a capacity of 6pounds of R-22. The system was not cooling well. Technician came and said that system needs refrigerant. He put in 6 pounds of R-22 @ $100/pound. System cooled wonderfully for two days and but now has is again not cooling well. The only difference I am seeing now is that with the AC running, there is a lot of ice formation at the point where one of the refrigerant lines meets the compressor unit that sits outside the house. I am wondering if anything is freezing in the lines preventing the refrigerant from circulating and transporting the heat away from the house.

Answered 7 years ago by Guest_9976822


If the frost is at only one small location, ESPECIALLY a joint or coupling, I would guess that you have a leak there. Before filling the system, the technician should have done a pressure hold test to determine if the system was leaking, BEFORE dumping hundreds of $ of Freon into it. Dramatically low (or zero) pressure inthe system shouldl have tld him to check for a leak FIRST.

This leak may be what caused your system to drain down originally, or it may be the fitting he hooked onto to fill the system - can't tell from your description. What you are seeing now may be because he did not tighten a connection or fill port right after filling, and may not be related to the original problem at all. That is quite possible,, considering how fast it apparently drained off.

AC systems do gradually bleed off the refrigerant pressure over the years due to diffusion through the pipes and threads, and through leakage past seals in the compressor, but a sudden loss of function (rather than gradual) means either a leak or a compressor unit problem.

The technician should come back, do the job right (locate the leak), and refill the system for you FOR FREE, because he did not do it right the first time.

Answered 7 years ago by LCD


An overcharge in an air conditioning is definitely a problem. It causes high operating pressures and loss of cooling It also decreases life expectancy of the compressor and loss of indoor comfort. Check the difference in temperature on a warm day from the return air to the supply air. The difference should be 18-22 degrees in a properly ducted system with a clean air filter and normal air flow. 20 degrees is usually optimal. If the temperature difference is lower or higher you should have a compenent service company check the system.

Answered 6 years ago by PoppyRoss

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