Cycling a/c or not? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chevydog66 · 08-20-2013, 10:37 PM

So how do you make the a/c compressor cycling. Is it better or more efficient?

cableguy0 · 08-20-2013, 10:45 PM

The compressor has to cycle. If it didn't cycle it would either blow the hoses open or the compressor itself. The compressor cycling is done through pressure switches.If it doesn't cycle your system will blow apart somewhere.

chevydog66 · 08-20-2013, 10:52 PM

I have the POA update valve for R134 on my 72 GMC with 6.0 ls dbc. Sanden 508 compressor, but the rest of the hardware is original style for the truck. Do I need to install a trinary switch? If so where?

clinebarger · 08-21-2013, 08:37 PM

The compressor needs to be shut down at anything Below 15 psi on the Low Side.
The compressor needs to be shut down at anything Above 350 psi on the High Side.

On an Expansion Valve system the Trinary will mount to the receiver dryer. Yes, Every system needs a fail safe.

On an efficient, Properly charged A/C system.....The compressor should not cycle on a Hot 95+ degree day. But I doubt your system is very efficient if your using an R-12 tube & fin condenser?

chevydog66 · 08-21-2013, 08:48 PM

I'm using a R 134 tube and fin condensor. How do I mount a switch on original style drier?
Posted via Mobile Device

clinebarger · 08-21-2013, 09:23 PM

I forgot the replacement driers don't have a port, You have a #6 hose running between the Drier & Expansion valve? Vintage has a "Crimp-On, In-line" trinary kit part# 24678-VUS.

I use Parker Receiver Driers & Aluminum Parallel Flow condensers only.

chevydog66 · 08-21-2013, 10:44 PM

Thanks for the info. Do you have a part # for the Parker drier?
Posted via Mobile Device

**Clyde65** · 08-22-2013, 05:52 PM

Hey Clinebarger, give me a pm when you can, your PM's are full also
Posted via Mobile Device

chevydog66 · 08-29-2013, 05:29 PM

The Vintage Air tech support line was absolutely no help. He couldn't tell me how to wire my Original type system.

chevydog66 · 08-29-2013, 05:41 PM

The Old Air tech support guy told me I don't need a Trinary switch. I am running the clutch fan on my LS motor in the original truck shroud. The clutch cycling switch that is built into the POA update valve is all I need as long as high and low side pressures are correct. 150-250psi on the high side or 2.5 times ambient temperature, and 35-45 psi on the low side.

clinebarger · 08-29-2013, 08:12 PM

If your clutch fan is moving enough air across the condenser......He is correct.

ls1nova71 · 08-29-2013, 10:19 PM

Quote:

Originally Posted by chevydog66

as long as high and low side pressures are correct. 150-250psi on the high side or 2.5 times ambient temperature, and 35-45 psi on the low side.

And as long as you never get in a wreck, you don't need seatbelts..... But you never know. Personally, if it were me and I was putting together an A/C system that was anything other than a factory installed, completely stock set up, I would put h high pressure switch in it too.

Blackpony · 08-29-2013, 09:33 PM

mine is setup using the factory wiring and switches. it stays on all the time and blows ice cold! no problems thus far 8 years later....

08-20-2013, 10:37 PM	#1
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	Cycling a/c or not? So how do you make the a/c compressor cycling. Is it better or more efficient? __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up

08-20-2013, 10:45 PM	#2
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	Re: Cycling a/c or not? The compressor has to cycle. If it didn't cycle it would either blow the hoses open or the compressor itself. The compressor cycling is done through pressure switches.If it doesn't cycle your system will blow apart somewhere. __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

08-20-2013, 10:52 PM	#3
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	Re: Cycling a/c or not? I have the POA update valve for R134 on my 72 GMC with 6.0 ls dbc. Sanden 508 compressor, but the rest of the hardware is original style for the truck. Do I need to install a trinary switch? If so where? __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up

08-21-2013, 08:37 PM	#4
clinebarger Senior Member Join Date: May 2009 Location: Fort Worth, TX Posts: 6,370	Re: Cycling a/c or not? The compressor needs to be shut down at anything Below 15 psi on the Low Side. The compressor needs to be shut down at anything Above 350 psi on the High Side. On an Expansion Valve system the Trinary will mount to the receiver dryer. Yes, Every system needs a fail safe. On an efficient, Properly charged A/C system.....The compressor should not cycle on a Hot 95+ degree day. But I doubt your system is very efficient if your using an R-12 tube & fin condenser?

08-21-2013, 08:48 PM	#5
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	Re: Cycling a/c or not? I'm using a R 134 tube and fin condensor. How do I mount a switch on original style drier? Posted via Mobile Device __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up

08-21-2013, 09:23 PM	#6
clinebarger Senior Member Join Date: May 2009 Location: Fort Worth, TX Posts: 6,370	Re: Cycling a/c or not? I forgot the replacement driers don't have a port, You have a #6 hose running between the Drier & Expansion valve? Vintage has a "Crimp-On, In-line" trinary kit part# 24678-VUS. I use Parker Receiver Driers & Aluminum Parallel Flow condensers only.

08-21-2013, 10:44 PM	#7
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	Re: Cycling a/c or not? Thanks for the info. Do you have a part # for the Parker drier? Posted via Mobile Device __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up

08-22-2013, 05:52 PM	#8
Clyde65 1965 Chevy C10, 2005 4.8L/4l60 Join Date: Aug 2004 Location: DFW Texas Posts: 8,546	Re: Cycling a/c or not? Hey Clinebarger, give me a pm when you can, your PM's are full also Posted via Mobile Device __________________ Clyde65 Rebuild of Clyde http://67-72chevytrucks.com/vboard/s...84#post8338184 69 Aristocrat Lo Liner build http://67-72chevytrucks.com/vboard/s...84#post7561684 *support our troops!*

08-29-2013, 05:29 PM	#9
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	Re: Cycling a/c or not? The Vintage Air tech support line was absolutely no help. He couldn't tell me how to wire my Original type system. __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up

08-29-2013, 05:41 PM	#10
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	Re: Cycling a/c or not? The Old Air tech support guy told me I don't need a Trinary switch. I am running the clutch fan on my LS motor in the original truck shroud. The clutch cycling switch that is built into the POA update valve is all I need as long as high and low side pressures are correct. 150-250psi on the high side or 2.5 times ambient temperature, and 35-45 psi on the low side. __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up

08-29-2013, 08:12 PM	#11
clinebarger Senior Member Join Date: May 2009 Location: Fort Worth, TX Posts: 6,370	Re: Cycling a/c or not? If your clutch fan is moving enough air across the condenser......He is correct.

08-29-2013, 09:33 PM	#13
Blackpony Registered User Join Date: Feb 2013 Location: Aubrey, TX Posts: 308	Re: Cycling a/c or not? mine is setup using the factory wiring and switches. it stays on all the time and blows ice cold! no problems thus far 8 years later....



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