AC leak question - the lines


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Old 01-05-19, 06:16 AM
L
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AC leak question - the lines

Hey everyone, we have been having AC issues. Our AC was working perfectly fine until one day it broke. Turned out that our compressor and condenser broke and we replaced them. We then replaced the compressor several times bc of comprrssor issues such as loud, stopped working, etc.

Then the unit would stop cooling after a few days so we did a leak check. First, we put the air handler in the pool and there were no bubbles. Second, we inserted dye into the unit to see if it was the old unit. There were no leaks detected with the UV light. Then we did a line check. The repairman pressurized the lines with nitrogen. After 4 days, the small line went from 200 to 190, the big line went from 225 to 215. The repairman attributed the small loss in pressure to screwing in the gages. Because of these results we purchased a whole new unit. Now we are experiencing cooling issues again! The repair guy is saying there was a leak in the old unit and now the lines. This seems unlikely. When he puts the pressure gun near the soil it beeps as if there is a leak. Are these guns bull****? Could there be other causes of leaks? Why would there be no leaks in the lines until after the compressor broke? The lines are 10 years old and run under the house in a PVC pipe. Any insights or suggestions as to how we can work out these issues would be helpful!! Thanks!
 
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Old 01-05-19, 09:14 AM
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Welcome to the forums.

Sounds like a three ring circus there with the A/C system.

After 4 days, the small line went from 200 to 190, the big line went from 225 to 215.
Basically the system lost 10psi. That could be a connection loss or a leak. Since you've replaced the condenser and the air handler coil...... it doesn't leave much else beside a line leak.

Where the lineset comes out of the ground..... is it conduit too ?
Is that where the sniffer detects something ?

I don't have too much contact with underground refrigerant lines but from what I've seen done is to use large PVC pipe where the lineset is pulled in after the PVC is installed. In this way the old lines could be pulled out and new pulled in.
 
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Old 01-05-19, 01:00 PM
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So the sniffer detects the leak at both ends - where the pvc comes out of the ground and by the air handler. I don’t understand why the line test wouldn’t have revealed this leak before though? How could a leak appear almost overnight after the new unit was installed? Also he didn’t do the sniff test before the $200 nitrogen test. Now he wants $800 to run new lines under the house, it might be over 40 feet. We bought the new unit based on the result of the nitrogen test. Now we’re out a bunch of money, is it now his responsibility to fix the lines for no labor cost since he messed up the test?
 
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Old 01-05-19, 04:18 PM
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So the sniffer detects the leak at both ends - where the pvc comes out of the ground and by the air handler.
Sure..... especially if the leak is large enough. I wouldn't consider a sniff test to be a reliable test of an underground problem but I'd sure want a reliable pressure test.

is it now his responsibility to fix the lines for no labor cost since he messed up the test?
Good question. I wouldn't expect him to do it for free because whether or not he didn't determine it was leaking..... it would have still needed replacing. I would consider a reduced rate.
 
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Old 01-05-19, 06:00 PM
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You had to put the whole air handler in a pool to check for leaks?!?!
I’ve been in this trade since 2001 and never had to do such a thing.
Compressors are often murdered via other causes vs just failing. So if you’ve experienced multiple repeat failures there’s a major issue someone is missing.
 
 

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