Pressures Equalize Instantly

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CrazyMel
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Pressures Equalize Instantly

Postby CrazyMel » Sun Sep 08, 2019 3:04 pm

Guys, please help me with your expert opinions. My car is honda civic 2008. AC is not cooling. Static pressure is 100psi at 100 F temperature. While AC is on with engine idle i have around 30 psi low side and 150 psi high side and never cycles. When i turn off the AC, pressures equalize instantly back to 100 psi i mean i turned off the ac and look at gauges it was 100 psi. Fan is working fine. I doubt its a bad expansion valve. What do you guys think ? Recently i went to a mechanic and cleaned all the lines and put a new condenser (with dryer). Cleaned valve and evaporator as well. It worked for a couple of days and suddenly started to blow warm air again.
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bohica2xo
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Re: Pressures Equalize Instantly

Postby bohica2xo » Mon Sep 09, 2019 6:35 pm

You have a leak. It is undercharged, just a few days after service.
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Cusser
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Re: Pressures Equalize Instantly

Postby Cusser » Mon Sep 09, 2019 7:59 pm

bohica2xo wrote:You have a leak. It is undercharged, just a few days after service.


Take it back to the shop, it's covered by their warranty.
CrazyMel
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Re: Pressures Equalize Instantly

Postby CrazyMel » Mon Sep 09, 2019 10:10 pm

bohica2xo wrote:You have a leak. It is undercharged, just a few days after service.


They did a pressure test to find leaks and found nothing. Besides, static pressure and working pressures are very good as i mentioned. I believe its supposed to blow cold air at those pressures. Please correct me if im wrong. What do you think about the fact that the pressures equalize instantly ?
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Cusser
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Re: Pressures Equalize Instantly

Postby Cusser » Tue Sep 10, 2019 5:53 am

CrazyMel wrote:
bohica2xo wrote:You have a leak. It is undercharged, just a few days after service.

I believe its supposed to blow cold air at those pressures.


CrazyMel wrote:While AC is on with engine idle i have around 30 psi low side and 150 psi high side

Should really measure such pressures at bout 2000 rpm. At 2000 rpm at 100F, I would expect more like 35 psi and 250 psi. We assume the cooling was OK when you picked the car up at the shop, then a few days later was not cooing well. That indicates a leak.
CrazyMel
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Re: Pressures Equalize Instantly

Postby CrazyMel » Tue Sep 10, 2019 6:27 am

Cusser wrote:
CrazyMel wrote:
bohica2xo wrote:You have a leak. It is undercharged, just a few days after service.

I believe its supposed to blow cold air at those pressures.


CrazyMel wrote:While AC is on with engine idle i have around 30 psi low side and 150 psi high side

Should really measure such pressures at bout 2000 rpm. At 2000 rpm at 100F, I would expect more like 35 psi and 250 psi. We assume the cooling was OK when you picked the car up at the shop, then a few days later was not cooing well. That indicates a leak.


Cooling was really good for 2-3 days and it was not a gradual decrease which would have happened if it was a leak. Cooling dispappeared suddenly. This happened more than a week back. Still there is a static pressure of 100 psi so i belive if there was a leak this should be much less by now. I was alone so couldnt check pressures @ 2000 rpm. Anyway, there's a new expansion valve on the way i will insrall it and let you know the results
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bohica2xo
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Re: Pressures Equalize Instantly

Postby bohica2xo » Tue Sep 10, 2019 10:35 am

It would have a static pressure of 100 psi with a single ounce of refrigerant in it. That is the nature of refrigerant gasses.

You have a leak. It crossed below the critical charge weight & quit cooling.

But keep throwing cheap online auction parts at it and you may accidentally fix the leak along the way...
CrazyMel
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Re: Pressures Equalize Instantly

Postby CrazyMel » Tue Sep 10, 2019 11:20 am

Probably you are right. But then why couldnt we catch the leak with pressure test ? Tried with UV dye as well.
Can expansion valve leak from somewhere other than the connections?
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Cusser
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Re: Pressures Equalize Instantly

Postby Cusser » Tue Sep 10, 2019 4:06 pm

Remember that service valve caps must be intact to seal a system - check those !!!
CrazyMel
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Re: Pressures Equalize Instantly

Postby CrazyMel » Tue Sep 10, 2019 11:18 pm

Cusser wrote:Remember that service valve caps must be intact to seal a system - check those !!!

Checked this already. No issues with the valves or caps.
I have some doubt about compressor itself as well. Because pressures equalize as soon as i turn off the system. Did some research in the internet and it was mentioned somewhere as a symptom of bad discharge valve inside compressor.

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