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Discussion Starter · #1 ·
Hello everyone I am at a sticking point on troubleshooting my AC problem and was hoping for some input. I have a older Lennox 2.5 ton central air unit connected to a Pulse g14 furnace and the other day when I went to turn it on for the first time this year it came on fan but the air flow from the vents was not very good.

I ended up taking the blower out and cleaned the cage and the bottom of the heat exchanger(they were both pretty dirty as the previous owner had let the filter get clogged to the point that it had popped off). This increased the airflow from the registers quite a bit and yesterday it was about 87F out and I had the AC set to 72 to see how it would do. It came on about 11:30am and ran until I went to bed at which point it was now 75 inside.

So I get up around midnight and notice its now at 73 and still running but the air from the registers is low again so I figure it must be iced up. I went down and removed the panels to view the evaporator and sure enough it was iced up but not uniformly. the upper half of one side was iced while the bottom was not and the left and right sections in the middle on the other side were frozen but the rest was not.

Moving on today it had thawed and I turned it on again and checked out the icing again when it started and the spots that are not freezing up are not even cold to the touch. I can run my hand about an inch above the coil all over and feel warm and cold spots. What can cause this knowing that the airflow is fine across the coil??? Low R22? Compressor going out? Any input woul dbe much appreciated. I have someone coming out to check it out tomorrow but I like to be as much informed as I can be. Thanks!
 

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My first guess is you are low on R-22, but as mentioned you will need gauges to know that. If you filter is clean and the airflow good, you just have to wait for someone to show up.

Let us know what you find, if you are in doubt about what you are told.
 

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Sounds like you have a leak and its low on charge.
 

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Discussion Starter · #5 ·
Thanks for the replies. The tech just left and confirmed that I was low on R-22 1lb 9oz was added and it seems to be cooling much better now but he ageed that there must be a leak in the system. He checked the major joints with a liquid test like you would test a tire looking for bubbles but did not find anything. He said the leak might be in one of the coils and to just keep an eye on it since the system is old (1988) and that it may be fine for the rest of the summer and to think about getting a new system. He also mentioned the head pressure was a little high but said that is common with a old compressor. Whats your thoughts?
 

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Could mean he over charged it a bite by accident.
Or that your outdoor coil is dirty.
Or that there is a restriction in the system, and its slightly overcharged.

Guess he didn't check SH and SC.
That would have told him what was causing the high head pressure.
 

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If indeed you have leak, which seems likely, it is just a matter of time before it will need more attention. It might be time to start getting quotes on a new system, or consider if you want to put money into repairing it.

I would argue a 21 year old system is over or at its end of life.
 
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