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Duracool charging? [message #130447]

Thu, 16 June 2011 19:54

fred v

Messages: 999
Registered: April 2006
Location: pensacola, fl.

Karma: 0

Senior Member

i just replaced the dryer and vacuumed the system. with 2 cans of Duracool the pressure would fluctuate from zero to 10 PSI. i'm guessing the compressor was cutting in and out.

is this normal? temp at the vent was 55 to 60 with outside air at 85.

Fred V
'77 Royale RB 455
P'cola, Fl

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Re: [GMCnet] Duracool charging? [message #130470 is a reply to message #130447]

Thu, 16 June 2011 20:48

Ken Henderson

Messages: 8726
Registered: March 2004
Location: Americus, GA

Karma: 9

Senior Member

Fred,

I'd guess that with only 12 oz of HC12A, you weren't getting a steady
closure of the low pressure switch. It usually takes about 3 cans (18
oz) to fully charge the system & achieve the 20 psi low side pressure.

Ken H.

On Thu, Jun 16, 2011 at 8:54 PM, fred veenschoten wrote:
>
>
> i just replaced the dryer and vacuumed the system. with 2 cans of Duracool the pressure would fluctuate from zero to 10 PSI. i'm guessing the compressor was cutting in and out.
>
> is this normal? temp at the vent was 55 to 60 with outside air at 85.
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach

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Re: [GMCnet] Duracool charging? [message #130500 is a reply to message #130447]

Thu, 16 June 2011 22:33

emerystora

Messages: 4442
Registered: January 2004

Karma: 13

Senior Member

On Jun 16, 2011, at 6:54 PM, fred veenschoten wrote:

>
>
> i just replaced the dryer and vacuumed the system. with 2 cans of Duracool the pressure would fluctuate from zero to 10 PSI. i'm guessing the compressor was cutting in and out.
>
> is this normal? temp at the vent was 55 to 60 with outside air at 85.
>
> --
> Fred V
> '77 Royale RB 455
> P'cola, Fl

Fred

Forget about the pressure with just 2 cans. That is not enough of a charge. The GMC motorhome system takes just a little less than 3 cans or sometimes 3 full cans.
You should start the engine and turn on the air conditioner. After putting in two cans, run the engine at 1500 rpm and fill from the 3rd can until the low side pressure is about 20-21 psi. Run the system for at least 15 minutes and again check the pressure with the engine at 1500 rpm. Adjust the charge up or down to get the 20 psi.

Emery Stora
77 Kingsley
Santa Fe, NM

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Re: [GMCnet] Duracool charging? [message #130518 is a reply to message #130500]

Fri, 17 June 2011 00:57

Ken Burton

Messages: 10030
Registered: January 2004
Location: Hebron, Indiana

Karma: 10

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emerystora wrote on Thu, 16 June 2011 22:33

It took exactly 3 cans to fill up Dan's coach this spring.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

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Re: [GMCnet] Duracool charging? [message #130585 is a reply to message #130518]

Fri, 17 June 2011 12:17

Jon payne

Messages: 495
Registered: May 2008

Karma: 1

Senior Member

Guys can someone explain why you just service to 20 psi without considering OAT?

For sure the low side pressure will differ depending on OAT. So if the low side is adjusted to 20 PSI with the OAT at 90 deg (for example) wouldn't the pressure be too low and cause the compressor to cycle at temps lets say in the low 70's? With my limited knowledge of A/C servicing, 20 PSI on the low side would seem to be appropriate at OAT of 70 but not at 90 for example.

Thanks in advanced for setting me straight!

Jon

Jon Payne
76 Palm Beach
Westfield,IN

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