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| [GMCnet] A/C Question [message #366307] |
Tue, 24 August 2021 10:02  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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I need the opinions of those more HVAC knowledgeable than I am: Since the
pandemic kept us off the road for over a year, I find that the A/C no
longer works (equipped with a Sanden compressor and Duracool, it had
operated without attention for the previous 5 years or so).
A couple of days ago, I vacuumed the system down to near 30 in.HG. and left
it sitting until today, when it was still at almost that level. Then I
moved the vacuum hose to a fresh can of Duracool and opened the valves.
The low-side and high-side gauges both immediately indicated ~95 psi. Then
I started the engine and engaged the compressor. Neither gauge's needle
even flickered! Repeated compressor clutch cycles yielded the same
results: Click-clack of the compressor clutch and obvious rotation of the
compressor shaft -- yet NO needle movements.
I took a brass hammer and rather strenuously rapped the compressor (on
"hard parts") hoping I might shake something loose inside -- STILL no
needle movement with clutch cycling.
My diagnosis is that I have one of 3 problems in the Sanden compressor:
1. A sheared shaft; 2. A valve stuck open; or, 3. a busted piston -- in
that order of probablility. Does anyone, hopefully, have another/better
idea? Maybe even one that won't require compressor replacement?
It's looking less and less like I'll really need A/C in the GMC this year,
but I'd still like to get it working before I get still older and less able
to tinker, so Y'All's opinions will be greatly appreciated.
Ken H.
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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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| [GMCnet] Re: A/C Question [message #366308 is a reply to message #366307] |
Tue, 24 August 2021 10:49  |
Marsh Wilkes
Messages: 155
Registered: January 2004
Karma: -3
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Senior Member |
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Good Morning Ken,
All I have is a few dumb questions.
Are the service hoses newer, with check valves in the ends of the hose?
Are the Schrader valve depressors in the end of the hoses screwed out well
enough
that they are positively depressing the Schrader valves?
Does the compressor "sound" like it is running?
Does it load the engine noticeably?
How many cans do you normally use?
Is there any noticeable heating of the compressor discharge?
Just hoping for something other than a bad compressor.
I'm sure some one else will have some other ideas.
Good Luck with it anyway.
Good seeing you post regularly.
Marsh (rarely Post) Wilkes
Perry Florida
-----Original Message-----
From: Ken Henderson
Sent: Tuesday, August 24, 2021 11:02 AM
To: GMC Mail List
Subject: [GMCnet] A/C Question
I need the opinions of those more HVAC knowledgeable than I am: Since the
pandemic kept us off the road for over a year, I find that the A/C no
longer works (equipped with a Sanden compressor and Duracool, it had
operated without attention for the previous 5 years or so).
A couple of days ago, I vacuumed the system down to near 30 in.HG. and left
it sitting until today, when it was still at almost that level. Then I
moved the vacuum hose to a fresh can of Duracool and opened the valves.
The low-side and high-side gauges both immediately indicated ~95 psi. Then
I started the engine and engaged the compressor. Neither gauge's needle
even flickered! Repeated compressor clutch cycles yielded the same
results: Click-clack of the compressor clutch and obvious rotation of the
compressor shaft -- yet NO needle movements.
I took a brass hammer and rather strenuously rapped the compressor (on
"hard parts") hoping I might shake something loose inside -- STILL no
needle movement with clutch cycling.
My diagnosis is that I have one of 3 problems in the Sanden compressor:
1. A sheared shaft; 2. A valve stuck open; or, 3. a busted piston -- in
that order of probablility. Does anyone, hopefully, have another/better
idea? Maybe even one that won't require compressor replacement?
It's looking less and less like I'll really need A/C in the GMC this year,
but I'd still like to get it working before I get still older and less able
to tinker, so Y'All's opinions will be greatly appreciated.
Ken H.
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| [GMCnet] Re: A/C Question [message #366309 is a reply to message #366308] |
Tue, 24 August 2021 11:32 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Senior Member |
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I have a very similar problem, my Dash AC stopped working, I have a new Sanden from Jim K, it used to work great.
I hooked up my AC gauges and they sat there like the compressor wasn't running. It was, the pully was spinning, both had some pressure, so the system was not empty
I didn't beat on it with a hammer but I guess that didn't help you either LOL
I didn't notice any lines getting hot or cold to the touch
Keith Vasilakes
Mounds View MN
76 exRoyale
MicroLevel
________________________________
From: Marsh Wilkes
Sent: Tuesday, August 24, 2021 10:49 AM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] Re: A/C Question
Good Morning Ken,
All I have is a few dumb questions.
Are the service hoses newer, with check valves in the ends of the hose?
Are the Schrader valve depressors in the end of the hoses screwed out well
enough
that they are positively depressing the Schrader valves?
Does the compressor "sound" like it is running?
Does it load the engine noticeably?
How many cans do you normally use?
Is there any noticeable heating of the compressor discharge?
Just hoping for something other than a bad compressor.
I'm sure some one else will have some other ideas.
Good Luck with it anyway.
Good seeing you post regularly.
Marsh (rarely Post) Wilkes
Perry Florida
-----Original Message-----
From: Ken Henderson
Sent: Tuesday, August 24, 2021 11:02 AM
To: GMC Mail List
Subject: [GMCnet] A/C Question
I need the opinions of those more HVAC knowledgeable than I am: Since the
pandemic kept us off the road for over a year, I find that the A/C no
longer works (equipped with a Sanden compressor and Duracool, it had
operated without attention for the previous 5 years or so).
A couple of days ago, I vacuumed the system down to near 30 in.HG. and left
it sitting until today, when it was still at almost that level. Then I
moved the vacuum hose to a fresh can of Duracool and opened the valves.
The low-side and high-side gauges both immediately indicated ~95 psi. Then
I started the engine and engaged the compressor. Neither gauge's needle
even flickered! Repeated compressor clutch cycles yielded the same
results: Click-clack of the compressor clutch and obvious rotation of the
compressor shaft -- yet NO needle movements.
I took a brass hammer and rather strenuously rapped the compressor (on
"hard parts") hoping I might shake something loose inside -- STILL no
needle movement with clutch cycling.
My diagnosis is that I have one of 3 problems in the Sanden compressor:
1. A sheared shaft; 2. A valve stuck open; or, 3. a busted piston -- in
that order of probablility. Does anyone, hopefully, have another/better
idea? Maybe even one that won't require compressor replacement?
It's looking less and less like I'll really need A/C in the GMC this year,
but I'd still like to get it working before I get still older and less able
to tinker, so Y'All's opinions will be greatly appreciated.
Ken H.
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Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| [GMCnet] Re: A/C Question [message #366311 is a reply to message #366308] |
Tue, 24 August 2021 13:32 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Marsh,
None of your questions really have significant answers -- see them in CAPS:
On Tue, Aug 24, 2021 at 11:49 AM Marsh Wilkes wrote:
> Good Morning Ken,
>
> All I have is a few dumb questions.
> Are the service hoses newer, with check valves in the ends of the hose?
> NEW
> Are the Schrader valve depressors in the end of the hoses screwed out well
> enough
> that they are positively depressing the Schrader valves? YEP
> Does the compressor "sound" like it is running? NO
> Does it load the engine noticeably? NO
> How many cans do you normally use? 3 -- LESS THAN ONE RIGHT NOW
> Is there any noticeable heating of the compressor discharge? NO
> Just hoping for something other than a bad compressor. ME TOO!
> I'm sure some one else will have some other ideas.
> Good Luck with it anyway.
> Good seeing you post regularly.
>
> Marsh (rarely Post) Wilkes
> Perry Florida
>
>
>
>
>
>
>
>
> -----Original Message-----
> From: Ken Henderson
> Sent: Tuesday, August 24, 2021 11:02 AM
> To: GMC Mail List
> Subject: [GMCnet] A/C Question
>
> I need the opinions of those more HVAC knowledgeable than I am: Since the
> pandemic kept us off the road for over a year, I find that the A/C no
> longer works (equipped with a Sanden compressor and Duracool, it had
> operated without attention for the previous 5 years or so).
>
> A couple of days ago, I vacuumed the system down to near 30 in.HG. and left
> it sitting until today, when it was still at almost that level. Then I
> moved the vacuum hose to a fresh can of Duracool and opened the valves.
> The low-side and high-side gauges both immediately indicated ~95 psi. Then
> I started the engine and engaged the compressor. Neither gauge's needle
> even flickered! Repeated compressor clutch cycles yielded the same
> results: Click-clack of the compressor clutch and obvious rotation of the
> compressor shaft -- yet NO needle movements.
>
> I took a brass hammer and rather strenuously rapped the compressor (on
> "hard parts") hoping I might shake something loose inside -- STILL no
> needle movement with clutch cycling.
>
> My diagnosis is that I have one of 3 problems in the Sanden compressor:
> 1. A sheared shaft; 2. A valve stuck open; or, 3. a busted piston -- in
> that order of probablility. Does anyone, hopefully, have another/better
> idea? Maybe even one that won't require compressor replacement?
>
> It's looking less and less like I'll really need A/C in the GMC this year,
> but I'd still like to get it working before I get still older and less able
> to tinker, so Y'All's opinions will be greatly appreciated.
>
> Ken H.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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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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| [GMCnet] Re: A/C Question [message #366312 is a reply to message #366311] |
Tue, 24 August 2021 14:04 |
Marsh Wilkes
Messages: 155
Registered: January 2004
Karma: -3
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Senior Member |
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I didn't figure you were missing a whole lot, just giving you what
I could think of.
Sure seems odd.
It'll be interesting to see what the outcome is, it shore don't
seem to be a pumpin.
Knowing you, you'll tear down the compressor to see what happened.
Let us know.
Good talking with you.
Marsh
-----Original Message-----
From: Ken Henderson
Sent: Tuesday, August 24, 2021 2:32 PM
To: GMC Mail List
Subject: [GMCnet] Re: A/C Question
Marsh,
None of your questions really have significant answers -- see them in CAPS:
On Tue, Aug 24, 2021 at 11:49 AM Marsh Wilkes wrote:
> Good Morning Ken,
>
> All I have is a few dumb questions.
> Are the service hoses newer, with check valves in the ends of the hose?
> NEW
> Are the Schrader valve depressors in the end of the hoses screwed out well
> enough
> that they are positively depressing the Schrader valves? YEP
> Does the compressor "sound" like it is running? NO
> Does it load the engine noticeably? NO
> How many cans do you normally use? 3 -- LESS THAN ONE RIGHT NOW
> Is there any noticeable heating of the compressor discharge? NO
> Just hoping for something other than a bad compressor. ME TOO!
> I'm sure some one else will have some other ideas.
> Good Luck with it anyway.
> Good seeing you post regularly.
>
> Marsh (rarely Post) Wilkes
> Perry Florida
>
>
>
>
>
>
>
>
> -----Original Message-----
> From: Ken Henderson
> Sent: Tuesday, August 24, 2021 11:02 AM
> To: GMC Mail List
> Subject: [GMCnet] A/C Question
>
> I need the opinions of those more HVAC knowledgeable than I am: Since the
> pandemic kept us off the road for over a year, I find that the A/C no
> longer works (equipped with a Sanden compressor and Duracool, it had
> operated without attention for the previous 5 years or so).
>
> A couple of days ago, I vacuumed the system down to near 30 in.HG. and
> left
> it sitting until today, when it was still at almost that level. Then I
> moved the vacuum hose to a fresh can of Duracool and opened the valves.
> The low-side and high-side gauges both immediately indicated ~95 psi.
> Then
> I started the engine and engaged the compressor. Neither gauge's needle
> even flickered! Repeated compressor clutch cycles yielded the same
> results: Click-clack of the compressor clutch and obvious rotation of the
> compressor shaft -- yet NO needle movements.
>
> I took a brass hammer and rather strenuously rapped the compressor (on
> "hard parts") hoping I might shake something loose inside -- STILL no
> needle movement with clutch cycling.
>
> My diagnosis is that I have one of 3 problems in the Sanden compressor:
> 1. A sheared shaft; 2. A valve stuck open; or, 3. a busted piston -- in
> that order of probablility. Does anyone, hopefully, have another/better
> idea? Maybe even one that won't require compressor replacement?
>
> It's looking less and less like I'll really need A/C in the GMC this year,
> but I'd still like to get it working before I get still older and less
> able
> to tinker, so Y'All's opinions will be greatly appreciated.
>
> Ken H.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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| Re: [GMCnet] A/C Question [message #366313 is a reply to message #366307] |
Tue, 24 August 2021 14:36 |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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|
Ken,
If you can see the compressor's clutch drive plate (right there on the front)turning when you power the clutch and nothing is pumping, then the clutch must not be connected to the bevel part (Swash Plate? I forgot the name) the makes the pistons stroke. It can't be much else. The valves are all individual by cylinder, even if one was jammed, the others would still pump something. It is pretty much the same for the pistons, but if one of them broke loose, I would expect a tell-tale noise.
Unfortunately, the drive plate is mounted to the shaft with a flexible element, so you will have a hard time detecting a broken shaft by trying to wiggle it. You could put a wrench on the nut and try to spin the and see if you feel anything like pumping.....
I have only once had a Sanden open, but there are some good things on Sanden's own sight, and a coupled of good YT videos.
If you are sure that the clutch is turning the shaft, there are not many choices left.
Please let us know when you find out what happened.
Matt
Ken Henderson wrote on Tue, 24 August 2021 11:02I need the opinions of those more HVAC knowledgeable than I am: Since the pandemic kept us off the road for over a year, I find that the A/C no longer works (equipped with a Sanden compressor and Duracool, it had operated without attention for the previous 5 years or so).
A couple of days ago, I vacuumed the system down to near 30 in.HG. and left it sitting until today, when it was still at almost that level. Then I moved the vacuum hose to a fresh can of Duracool and opened the valves. The low-side and high-side gauges both immediately indicated ~95 psi. Then I started the engine and engaged the compressor. Neither gauge's needle even flickered! Repeated compressor clutch cycles yielded the same results: Click-clack of the compressor clutch and obvious rotation of the compressor shaft -- yet NO needle movements.
I took a brass hammer and rather strenuously rapped the compressor (on "hard parts") hoping I might shake something loose inside -- STILL no needle movement with clutch cycling.
My diagnosis is that I have one of 3 problems in the Sanden compressor: 1. A sheared shaft; 2. A valve stuck open; or, 3. a busted piston -- in that order of probablility. Does anyone, hopefully, have another/better idea? Maybe even one that won't require compressor replacement?
It's looking less and less like I'll really need A/C in the GMC this year, but I'd still like to get it working before I get still older and less able
to tinker, so Y'All's opinions will be greatly appreciated.
Ken H.
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] A/C Question [message #366314 is a reply to message #366307] |
Tue, 24 August 2021 14:43 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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think Matt is correct... it is not that complicated of a system.
if it is like my Sanden, at least it is easy to get on the bench to see, and it is not crazy heavy.... then again maybe it is hard to reach on your caddy 500??
clutch is probably most likely the issue especially with non-use.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: [GMCnet] A/C Question [message #366315 is a reply to message #366307] |
Tue, 24 August 2021 16:30 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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I have a 77 which I think was the first year for CCOT. Your 76 probably has a POA valve? Perhaps some gentle hammer taps there on the valve stuck open? I did get one on a 65 Olds to function by rapping on it.
Obviously at 1 can you are very undercharged, but need a pressure differential to add more
John Lebetski
Woodstock, IL
77 Eleganza II
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| [GMCnet] Re: A/C Question [message #366318 is a reply to message #366313] |
Tue, 24 August 2021 18:49 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Matt,
I think you're probably right -- the flexible coupling to the wobble plate
probably failed. Your note about there being a valve per cylinder pretty
well cinches it -- I don't know why I was only thinking about one valve.
Guess I'll pull it off and tear it down, even before ordering the
replacement, out of curiosity. Fortunately, on the Cad500, it's mounted
right up front in the Vee of the block -- easy to get to.
Thanks,
Ken H.
On Tue, Aug 24, 2021 at 3:36 PM Matt Colie wrote:
> Ken,
>
> If you can see the compressor's clutch drive plate (right there on the
> front)turning when you power the clutch and nothing is pumping, then the
> clutch
> must not be connected to the bevel part (Swash Plate? I forgot the name)
> the makes the pistons stroke. It can't be much else. The valves are all
> individual by cylinder, even if one was jammed, the others would still
> pump something. It is pretty much the same for the pistons, but if one of
> them
> broke loose, I would expect a tell-tale noise.
>
> Unfortunately, the drive plate is mounted to the shaft with a flexible
> element, so you will have a hard time detecting a broken shaft by trying to
> wiggle it. You could put a wrench on the nut and try to spin the and see
> if you feel anything like pumping.....
>
> I have only once had a Sanden open, but there are some good things on
> Sanden's own sight, and a coupled of good YT videos.
>
> If you are sure that the clutch is turning the shaft, there are not many
> choices left.
>
> Please let us know when you find out what happened.
>
> Matt
> Ken Henderson wrote on Tue, 24 August 2021 11:02
>> I need the opinions of those more HVAC knowledgeable than I am: Since
> the pandemic kept us off the road for over a year, I find that the A/C no
>> longer works (equipped with a Sanden compressor and Duracool, it had
> operated without attention for the previous 5 years or so).
>>
>> A couple of days ago, I vacuumed the system down to near 30 in.HG. and
> left it sitting until today, when it was still at almost that level. Then
>> I moved the vacuum hose to a fresh can of Duracool and opened the
> valves. The low-side and high-side gauges both immediately indicated ~95
> psi.
>> Then I started the engine and engaged the compressor. Neither gauge's
> needle even flickered! Repeated compressor clutch cycles yielded the same
>> results: Click-clack of the compressor clutch and obvious rotation of
> the compressor shaft -- yet NO needle movements.
>>
>> I took a brass hammer and rather strenuously rapped the compressor (on
> "hard parts") hoping I might shake something loose inside -- STILL no
>> needle movement with clutch cycling.
>>
>> My diagnosis is that I have one of 3 problems in the Sanden compressor:
> 1. A sheared shaft; 2. A valve stuck open; or, 3. a busted piston -- in
>> that order of probablility. Does anyone, hopefully, have another/better
> idea? Maybe even one that won't require compressor replacement?
>>
>> It's looking less and less like I'll really need A/C in the GMC this
> year, but I'd still like to get it working before I get still older and less
>> able
>> to tinker, so Y'All's opinions will be greatly appreciated.
>>
>> Ken H.
>
>
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] A/C Question [message #366319 is a reply to message #366307] |
Tue, 24 August 2021 22:41 |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
Karma: 4
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Senior Member |
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Wouldn't you need more than one can in an empty system to get the compressor to kick in?
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
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| [GMCnet] Re: A/C Question [message #366320 is a reply to message #366319] |
Tue, 24 August 2021 22:49 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Just have to jumper the low pressure switch harness to override the switch.
Unplug the harness from the switch. And connect the two wires together with
a jumper wire. The compressor will run, but if there is no refrigerant in
the system, don't run it for long that way. Once the compressor is running,
then you can add more refrigerant to the system and check for leaks and
pressures.
Jim Hupy
Salem, Oregon
On Tue, Aug 24, 2021, 8:41 PM wrote:
> Wouldn't you need more than one can in an empty system to get the
> compressor to kick in?
>
> Larry
> --
> Larry - Victoria BC -
>
> 1977 Palm Beach 40,000 miles, PO said everything working but forgot the
> word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system,
> 6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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| [GMCnet] Re: A/C Question [message #366322 is a reply to message #366319] |
Wed, 25 August 2021 03:45 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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I connect the compressor clutch directly to +12VDC, bypassing the low
pressure switch, so, no, the can's pressure (95psi) is what the gauges
show. Without the compressor "sucking" the gas, there's no way to put more
in.
Ken H.
On Tue, Aug 24, 2021 at 11:41 PM wrote:
> Wouldn't you need more than one can in an empty system to get the
> compressor to kick in?
>
> Larry
> --
> Larry - Victoria BC -
>
> 1977 Palm Beach 40,000 miles, PO said everything working but forgot the
> word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system,
> 6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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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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| [GMCnet] Re: A/C Question [message #366323 is a reply to message #366322] |
Wed, 25 August 2021 06:27 |
Dave Stragand
Messages: 307
Registered: October 2017
Karma: 0
|
Senior Member |
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Ken,
When you say gauges (plural) — are you using an AC manifold set? I know it’s a dumb question, but are you opening the center valve to allow the gas into the coach’s system?
-Dave
1978 Transmode near Pittsburgh
> On Aug 25, 2021, at 4:46 AM, Ken Henderson wrote:
>
> I connect the compressor clutch directly to +12VDC, bypassing the low
> pressure switch, so, no, the can's pressure (95psi) is what the gauges
> show. Without the compressor "sucking" the gas, there's no way to put more
> in.
>
> Ken H.
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1978 Transmode (403)
Pittsburgh, PA
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| Re: [GMCnet] A/C Question [message #366325 is a reply to message #366307] |
Wed, 25 August 2021 10:16 |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
Karma: 4
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Senior Member |
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On my car, the compressor doesn't kick in until I'm on the second or third can (car takes about 4). The vacuum created by the empty system should pull the gas, right? In my experience putting a can in a pail of warm water speeds up the intake.
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
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| [GMCnet] Re: A/C Question [message #366335 is a reply to message #366328] |
Wed, 25 August 2021 11:48 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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It sounds to me like the drive coupling (clutch) mechanism has failed. It
may be due to normal wear 'n tear, or something like a compressor stall or
lockup. Either way, it needs to come off and onto the bench for a good
look-see, or possible replacement compressor.
You mentioned that it was a Sanden, I believe. Don't know much about
the longevity of those compressors, but the old OEM compressors would
outlast you and me combined, properly maintained, and cool a 2 bedroom
house to boot.
Jim Hupy
Salem, Oregon
On Wed, Aug 25, 2021, 9:19 AM roy keen wrote:
> If both hi and low gages are reading 96 and the pump is rotAting the
> compressor is shot
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
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| [GMCnet] Re: A/C Question [message #366336 is a reply to message #366323] |
Wed, 25 August 2021 11:51 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Yes, using a gauge set with the center and low pressure valves open.
Ken H.
On Wed, Aug 25, 2021 at 7:28 AM Dave Stragand wrote:
> Ken,
>
> When you say gauges (plural) — are you using an AC manifold set? I know
> it’s a dumb question, but are you opening the center valve to allow the gas
> into the coach’s system?
>
> -Dave
> 1978 Transmode near Pittsburgh
>
>> On Aug 25, 2021, at 4:46 AM, Ken Henderson
> wrote:
>>
>> I connect the compressor clutch directly to +12VDC, bypassing the low
>> pressure switch, so, no, the can's pressure (95psi) is what the gauges
>> show. Without the compressor "sucking" the gas, there's no way to put
> more
>> in.
>>
>> Ken H.
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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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| [GMCnet] Re: A/C Question [message #366337 is a reply to message #366325] |
Wed, 25 August 2021 11:53 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Your compressor doesn't kick in with the first cans because the low
pressure cutoff switch is not satisfied. I'm bypassing that switch and
powering the clutch straight from a 12VDC supply.
Ken H.
On Wed, Aug 25, 2021 at 11:17 AM wrote:
> On my car, the compressor doesn't kick in until I'm on the second or third
> can (car takes about 4). The vacuum created by the empty system should pull
> the gas, right? In my experience putting a can in a pail of warm water
> speeds up the intake.
>
> Larry
> --
> Larry - Victoria BC -
>
> 1977 Palm Beach 40,000 miles, PO said everything working but forgot the
> word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system,
> 6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| [GMCnet] Re: A/C Question [message #366338 is a reply to message #366328] |
Wed, 25 August 2021 11:54 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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I agree with you -- neither needle even quivers!
Ken H.
On Wed, Aug 25, 2021 at 12:19 PM roy keen wrote:
> If both hi and low gages are reading 96 and the pump is rotAting the
> compressor is shot
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] A/C Question [message #366355 is a reply to message #366307] |
Thu, 26 August 2021 10:24 |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
Karma: 4
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Senior Member |
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My Jaguar has a Sanden compressor that had a problem so I had to dismantle it to change the bearings and clutch.
The compressor is really two separate units, front clutch etc and the back piston area. I didn't do any work on the rear of the unit.
Apart from needing an inside and outside circlip pliers, I picked up a compressor tool kit on ebay for not too much money. The kit was somewhat useful as I remember but I think probably more useful servicing units like the Harrison.
Some very good service videos on YouTube but you've probably viewed those already.
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
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