High low pressure

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Mijomoore
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Joined: Sat Jul 30, 2022 2:39 pm

High low pressure

Post by Mijomoore »

My wife’s 2011 Toyota Sienna ac performance is poor, barely blows cold out of the vents. I stuck my gauges on and high side is 300 and low side is 125. I have not added any Freon. If I let it sit overnight the pressure will equalize to 120 high and low. Any ideas what would cause this?
tbirdtbird
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Re: High low pressure

Post by tbirdtbird »

Are the electric condenser fans running while the AC is engaged? Is there a mechanical fan with a viscous clutch that may be bad?

Is the cabin on recirc?

Testing with a gage set involves an RPM of 1500-1800, max cabin fan, max cool setting, doors open, recirc selected, and give the ambient temp

Do you have an infared temp gun? If so, shoot the temp of the pipe into and the pipe out of the condenser at these conditions, and post back

Is this new behavior? Anyone work on the system lately? Has freon with sealer been added (this is VERBOTEN)
When considering your next auto A/C purchase, please consider the site that supports you: www.ACKits.com
Mijomoore
Posts: 12
Joined: Sat Jul 30, 2022 2:39 pm

Re: High low pressure

Post by Mijomoore »

Are the electric condenser fans running while the AC is engaged? Is there a mechanical fan with a viscous clutch that may be bad?
Both electric fans are on.

Is the cabin on recirc?
Yes

Testing with a gage set involves an RPM of 1500-1800, max cabin fan, max cool setting, doors open, recirc selected, and give the ambient temp.
rpm was 1500, max cool, windows rolled down. Ambient temp was 94 degrees.

Do you have an infared temp gun? If so, shoot the temp of the pipe into and the pipe out of the condenser at these conditions, and post back.
I will check that tomorrow.

Is this new behavior? Anyone work on the system lately? Has freon with sealer been added (this is VERBOTEN). Yes new behavior this summer.
I replaced a plugged condenser a few years ago. Charged system back to appropriate refrigerant amount and high and low pressures were perfect. Haven’t had to touch it since then. No Freon with sealer has been added.
tbirdtbird
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Joined: Sat May 02, 2020 1:48 pm
Location: Texas

Re: High low pressure

Post by tbirdtbird »

OK, awaiting the results of the condenser temps.

In the meantime, why was the previous condenser clogged? Did a compressor grenade? And if so, where was the replacement comp sourced?
When considering your next auto A/C purchase, please consider the site that supports you: www.ACKits.com
Mijomoore
Posts: 12
Joined: Sat Jul 30, 2022 2:39 pm

Re: High low pressure

Post by Mijomoore »

Several years ago it had low low pressure but high pressure was ok. I mis diagnosed it as a weak compressor. Bought a brand new Denso compressor, condenser, expansion valves. Realized original compressor was fine and condenser was plugged so saved the old compressor. New compressor lasted 4 months and failed. Installed original compressor with another new condenser, cleaned expansion valves and flushed system and it’s been working fine for several years.
tbirdtbird
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Re: High low pressure

Post by tbirdtbird »

I don't see mention of a new filter/drier at any point...
When considering your next auto A/C purchase, please consider the site that supports you: www.ACKits.com
Mijomoore
Posts: 12
Joined: Sat Jul 30, 2022 2:39 pm

Re: High low pressure

Post by Mijomoore »

The drier is made onto the condenser.
Mijomoore
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Joined: Sat Jul 30, 2022 2:39 pm

Re: High low pressure

Post by Mijomoore »

165 degrees inlet and 132 outlet on the condenser.
goslo

Re: High low pressure

Post by goslo »

non approved post - sensorship
Last edited by goslo on Sun Jul 31, 2022 5:52 pm, edited 1 time in total.
tbirdtbird
Preferred Member
Posts: 1241
Joined: Sat May 02, 2020 1:48 pm
Location: Texas

Re: High low pressure

Post by tbirdtbird »

"165 degrees inlet and 132 outlet on the condenser."

Those are good readings.

Does this car have an accumulator (large aluminum canister just in front of the firewall on the pass side with a pipe in and a pipe out?
Now, are you able to get your fingers on the pipe into and out of the evap, or at least is the suction line back to the comp cold? (The pipe into the accumulator). The evap is usually hard to get to, but if you can do the finger test, it would help.
How much oil was installed with each compressor change? Was the system ever taken back to bare metal, meaning was all the oil blown out, and fresh installed by weight?

Awaiting those answers. We may be getting close to having the system vacuumed down and recharged by weight. You may have too much oil.
If you ever blow out a system, do not use shop air, it is heavily laden with water vapor. Dry nitrogen is fine and can be obtained at welding shops. And we do not pressure test over 100 psi, you can damage the coils
When considering your next auto A/C purchase, please consider the site that supports you: www.ACKits.com
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