Dash Air - Update [message #90430] |
Tue, 29 June 2010 11:25 |
Jon payne
Messages: 495 Registered: May 2008
Karma: 1
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Senior Member |
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Hi All,
Well I thought I would give some updates on my Dash-Air rebuild I started last month. To recap I replaced the compressor, AC lines, expansion valve, drier and themostatic switch. I also flushed the evaporator and condenser. In May, during the work rally in Hamilton OH, I attempted to service with Duracool. We vacuumed down the system but found it would not hold a vacuum. Was loosing something like 5"HG in 10 minutes so no doubt a big leak. Checked all the fittings and o-rings but could not find an obvious leak. It was theorized the the compressor's shaft seal could be the culprit being that it was new and is of course designed to hold pressure not a vacuum. At this point we ran out of time so we just added about 30lbs of R134 to see if it would hold pressure (thinking the that shaft seal was the culprit).
Well 24 hours later it was still holding the 30 lbs. So I evacuated the R134 and serviced with Duracool. That was one month ago and it is still holding a charge. Regarding cooling I am seeing about a 25Deg delta between ambient and the duct outlet temp. For example, the day I serviced the AC it was around 85deg and I was seeing around 61 deg outlet. I was expecting colder air. Over the past month I have been monitoring the duct temps and the other day the ambient was around 75 and I was seeing duct temps between 48 and 50 Deg.
Do the above mentioned duct temps seem about right? Note that I serviced the low pressure side to around 21-22 psi @1500rpm.
Jon
Jon Payne
76 Palm Beach
Westfield,IN
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Re: [GMCnet] Dash Air - Update [message #90432 is a reply to message #90430] |
Tue, 29 June 2010 11:29 |
emerystora
Messages: 4442 Registered: January 2004
Karma: 13
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Senior Member |
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On Jun 29, 2010, at 10:25 AM, Jon Payne wrote:
>
>
> Well 24 hours later it was still holding the 30 lbs. So I evacuated the R134 and serviced with Duracool. That was one month ago and it is still holding a charge. Regarding cooling I am seeing about a 25Deg delta between ambient and the duct outlet temp. For example, the day I serviced the AC it was around 85deg and I was seeing around 61 deg outlet. I was expecting colder air. Over the past month I have been monitoring the duct temps and the other day the ambient was around 75 and I was seeing duct temps between 48 and 50 Deg.
>
> Do the above mentioned duct temps seem about right? Note that I serviced the low pressure side to around 21-22 psi @1500rpm.
>
> Jon
>
Drop it to 19 or 20 and you should see it run colder. The less the charge the colder it is. However, if you get it too low the evaporator might freeze up with ice and stop the air flow.
I was running 15 psi at one time in New Mexico and it was really cold. But then when I drove east toward Florida my evaporator iced up. So i increased the psi to 20 by adding more HC12a and it was plenty cold with no freezeup even in high humidity locations.
Emery Stora
77 Kingsley
Santa Fe, NM
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