AC insanity!! Help!!

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ROFF

ROFF

Joined
Oct 6, 2017
Threads
20
Messages
97
Location
Texas, Rockwall Co
So it started out as an expansion valve replacement. But then it crossed my mind that at some point other failures will happen in the old system so I decided to replace the entire AC system. Replaced the expansion valve, evap, compressor, condenser, and receiver. Hoses were fine.

Everything hooked up and now it won't take a charge. Pulled a vacuum, got some R12 in there, jumped the compressor to get it moving and nothing.

Compressor now will turn on but runs continuously with no cold air and no cycling.

Any thoughts? Did I get a bad expansion valve?

It was a real paint to get the refrigerant in there in the first place. Its R12 but used compatible oil so can switch right over to 134 if need be but obviously that is irrelevant at this stage.



Thanks
Brandon
 
I'm assuming yes. Both sides take and hold a vacuum.

This is all new to me and I'm learning. I probably know just enough right now to be stupid.
 
I'm just asking obvious stuff, cuz sometimes that is what's overlooked...

Are you using a set of gauges (connectors) that work on the R12 ports ? (R134a gauge set won't).
 
Yea all is correct. I'm not actually doing it all. I have a guy doing most along side.

He's stumped as well but he did say he's experienced faulty expansion valves right out of the package. All signs point to that so we will likely change it and try again even tho it's new.
 
Re reading my original post I forgot to mention that it's actuallly taken about a can and a half but with reluctance. Got some in the high side from the vacuum with it shut down.

Just doesn't circulate.

Air isn't cooled the least bit.
 
I
ROFF said:
Yea all is correct. I'm not actually doing it all. I have a guy doing most along side.

He's stumped as well but he did say he's experienced faulty expansion valves right out of the package. All signs point to that so we will likely change it and try again even tho it's new.
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I believe the expansion valve converts the liquid to gas (or vice Versa) and it sounds like you’re getting no action there. How does the site glass look.
 
ROFF said:
Re reading my original post I forgot to mention that it's actuallly taken about a can and a half but with reluctance. Got some in the high side from the vacuum with it shut down.

Just doesn't circulate.

Air isn't cooled the least bit.
Click to expand...
I do know (at least with 134) you don’t load through the high side. You should have that side closed off and open only the low when under vacuum. Regardless, I don’t think that’s your issue though. Hopefully CD can weigh in @ceylonfj40nut
 
Thanks. Yea all symptoms say expansion valve. Just wouldn't think a new Denso one would be bad.

Guess will try that and see.

Can they be stubborn to get working at all?

The FSM calls for filling the high side with liquid with the compressor off. Which is what we did.
 
ROFF said:
Re reading my original post I forgot to mention that it's actuallly taken about a can and a half but with reluctance. Got some in the high side from the vacuum with it shut down.

Just doesn't circulate.

Air isn't cooled the least bit.
Click to expand...
I do know (at least with 134) you don’t load through the high side. You should have that side closed off and open only the low when under vacuum. Regardless, I don’t think that’s your issue though. Hopefully CD can weigh in @ceylonfj40nut
 
ROFF said:
So it started out as an expansion valve replacement. But then it crossed my mind that at some point other failures will happen in the old system so I decided to replace the entire AC system. Replaced the expansion valve, evap, compressor, condenser, and receiver. Hoses were fine.

Good move.

Everything hooked up and now it won't take a charge. Pulled a vacuum, got some R12 in there, jumped the compressor to get it moving and nothing.

How long did you pull a vacuum? Did you have both high and low sides hooked up and open? How many in. Hg did it pull on the gauge?

Compressor now will turn on but runs continuously with no cold air and no cycling.

Any thoughts? Did I get a bad expansion valve?

It was a real paint to get the refrigerant in there in the first place. Its R12 but used compatible oil so can switch right over to 134 if need be but obviously that is irrelevant at this stage.

What oil did you use and how much?

Thanks
Brandon
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^^^^^ Expand for replies
 
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ROFF said:
Thanks. Yea all symptoms say expansion valve. Just wouldn't think a new Denso one would be bad.

It probably is not bad. What were your high and low side pressures?


Can they be stubborn to get working at all?

No, they are generally trouble free.

The FSM calls for filling the high side with liquid with the compressor off. Which is what we did.

This is correct. You want to charge your first can (about 12 ounces) into vacuum, as a LIQUID into the high side service port (engine OFF, A/C off). Then shut the high side valve and leave it off. You will not be opening it again. Leave it hooked up because we need to monitor the high side pressure. You will finish charging the system through the low side...as a vapor (engine running, A/C on).

But...before you do this...we need to know the answers to some questions.
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I don't recall the exact oil but it was R12/134 compatible.

Pulled a vacuum on both sides before charging.

Pressures were about 100L and 90H

Had to wrap it up and head to work for a few days.

Thanks!!
 
ROFF said:
I don't recall the exact oil but it was R12/134 compatible.

OK, probably an Ester oil. Did it come with the new compressor and do you know how much (total) was put in the system?

Pulled a vacuum on both sides before charging.

Good.

Pressures were about 100L and 90H

OK, well this should tell us that TXV is not likely the culprit. IF there were significant blockage there...you would be showing High (high side pressure) and Low (low side) pressure (depending on how much refrigerant there is in the system). Instead we are seeing almost equal pressure. Do you happen to remember the ambient (outside temperature at the time)?

It sounds like you were able to get about 12 ounces into the system...through the high side charge and then had difficulty any (or much) into it as vapor through the low side, correct?

I'm thinking the low side hose or schrader valve at the low side service port is obstructed. That would account for the difficulty in getting a charge into the system. It would also tend to show you what is essentially the 'static' pressure of the refrigerant (on the low side hose, or can pressure) since it is effectively isolated from the compressor.

Had to wrap it up and head to work for a few days.

No trouble, we need to do a little detective work when you get back.
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Thanks s lot!

Temps were 70-75. Typical socal morning.

Started with liquid in the low side. Which I think is NOT what the FSM calls for. Followed by liquid in tbe high side.

Is it possible that the low side is now "contaminated" with liquid when it needs to be vapor and thus at ambient temp and not triggering the expansion valve to open because of the "high" temp? The pressure switch is signaling so there is something in there and the compressor turns on but no flow.


Wait that's all wrong I think
 
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