Search found 611 matches

by bohica2xo
Thu Jul 11, 2019 9:30 pm
Forum: Automotive Air Conditioning Forum
Topic: Building a custom R134a system for 1985 square body Blazer
Replies: 9
Views: 385

Re: Building a custom R134a system for 1985 square body Blazer

Any positive displacement pump is variable output by changing the RPM The electrically commutated PMDC motors are fairly efficient over a broad speed range. So there is no need to use a variable displacement compressor with a variable speed motor. A little Sanden with a direct drive (no belt losses)...
by bohica2xo
Tue Jul 09, 2019 6:10 pm
Forum: Automotive Air Conditioning Forum
Topic: Building a custom R134a system for 1985 square body Blazer
Replies: 9
Views: 385

Re: Building a custom R134a system for 1985 square body Blazer

Use a similar sized valve - forgot about the external equalization. Unless you live in some remote spot, there is an industrial hose shop somewhere nearby. The Aeroquip stuff works well, but you need to use the whole system - hose, fittings & tool Some odd MVAC fittings are not available from Ae...
by bohica2xo
Mon Jul 08, 2019 3:46 pm
Forum: Automotive Air Conditioning Forum
Topic: Old R12 System
Replies: 4
Views: 395

Re: Old R12 System

If you had both service valves closed during testing, then yes the high side is too low for a good compressor.

Given that you have a POA valve, this is probably an A6 compressor?

Year / Make / Model would be a big help in helping you diagnose this system
by bohica2xo
Mon Jul 08, 2019 3:42 pm
Forum: Automotive Air Conditioning Forum
Topic: 1979 Lincoln R12 System - Blows colder at idle
Replies: 2
Views: 281

Re: 1979 Lincoln R12 System - Blows colder at idle

I believe the 1979 Mark V still had a POA valve on the low side. The low side should remain steady, and around 30 psi. That heater valve was a great idea 40 years ago. They are subject to the ravages of age, and poorly maintained cooling systems. Since it is 105f here in Las Vegas right now I would ...
by bohica2xo
Mon Jul 08, 2019 1:21 pm
Forum: Automotive Air Conditioning Forum
Topic: Building a custom R134a system for 1985 square body Blazer
Replies: 9
Views: 385

Re: Building a custom R134a system for 1985 square body Blazer

Use the TXV for the 1972 GM line - C20 / Suburban / Impala etc all used the same valve. Go ahead and use the accumulator along with a Receiver in the liquid line. I do this on TXV conversions, you get a second dryer. Add 1.5 to 2.0 ounces of oil for the added dessicant & the puddle in the bottom...
by bohica2xo
Mon Jul 08, 2019 1:07 pm
Forum: Automotive Air Conditioning Forum
Topic: 2009 Honda Accord Intermittent AC Cooling
Replies: 4
Views: 377

Re: 2009 Honda Accord Intermittent AC Cooling

Check the compressor clutch gap.

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by bohica2xo
Sun Jul 07, 2019 11:40 am
Forum: Automotive Air Conditioning Forum
Topic: AC stops working when I rev the engine (live data video)
Replies: 4
Views: 261

Re: AC stops working when I rev the engine (live data video)

No RPM readings in the video, so it is hard to determine what is going on there. The regulating valve never moves and a pressure sensor shows what may be the high side going all over the place. Without actual system pressure from both the low & high side & an RPM reference it is all guesswor...
by bohica2xo
Wed Jul 03, 2019 10:39 am
Forum: Automotive Air Conditioning Forum
Topic: Evap freezing at low fan speeds
Replies: 20
Views: 2586

Re: Evap freezing at low fan speeds

Rapid cycling, at HIGH HEAT LOADS is absolutely a problem. In systems controlled with pressure switches, rapid cycling at high heat loads is either a significant undercharge or cycling on the high pressure cutout switch. Almost always associated with CCOT systems. Your cycling occurs at minimum heat...
by bohica2xo
Tue Jul 02, 2019 8:51 pm
Forum: Automotive Air Conditioning Forum
Topic: Evap freezing at low fan speeds
Replies: 20
Views: 2586

Re: Evap freezing at low fan speeds

Same compressor, same clutch - either TXV or CCOT. I used the CCOT as a common example of a system that will cycle the clutch for it's entire life.

You seem to be obsessed with the cycling. It has probably done this since new. If it bothers you, turn on the rear system.

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by bohica2xo
Mon Jul 01, 2019 4:56 pm
Forum: Automotive Air Conditioning Forum
Topic: Evap freezing at low fan speeds
Replies: 20
Views: 2586

Re: Evap freezing at low fan speeds

Rapid cycling can happen with any CCOT system in the right climate conditions. It does not hurt anything, and the compressor / clutch is designed for cycling. The solenoid valve in your system shunts all of the refrigerant flow to the front TXV when closed. I would expect cycling on front operation ...

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