| [GMCnet] HVAC controls [message #353382] |
Tue, 31 March 2020 18:28  |
Hanson Email
Messages: 110
Registered: March 2020
Karma: -1
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Senior Member |
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OK Wizards;
I know someone can help me with this issue. It may get your attention off of
crimps and solder (zzzz) for a while. My heater valve (in the hose upfront)
has vacuum to it all the time. Can't really tell if it is more or less with
the control set to heater or off. On a previous '73-23',40 years ago
(really) I researched it and removed the vacuum valve and replaced it with a
ball valve so I could optimize the AC by eliminating any hot water going
through the core. First question is there an easy repair to the control unit
to actually turn on and off the various valves; 2nd question is there any
valves that really work; and 3rd question do you see any problems with
throwing that heater valve away and putting in a ball valve?
Thanks
Dean Hanson 75 Avion- up and raising.
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| Re: [GMCnet] HVAC controls [message #353384 is a reply to message #353382] |
Tue, 31 March 2020 19:00  |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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All of those vacuum controlled hose valve pretty much do not travel a full
90°, as you have already figured out. So, if the cables are adjusted to
completely close off the water flow, then you are unable to to achieve full
flow. So in summer, some hot water circulates through the heater core, and
the ac has to get rid of that heat, too.
A new valve will just fix the leaky old vacuum diaphram, and not stop
the water flow.
Many coach owners install a manual shut off valve, and switch it
summer and winter.
I just disconnected the vacuum linkage from my valve, and used a zip
tie to open it all the way for winter, or close it for summer. A 5 minute
fix. No valve swapping necessary.
Jim Hupy
Salem, Oregon
On Tue, Mar 31, 2020, 4:29 PM Hanson Email via Gmclist <
gmclist@list.gmcnet.org> wrote:
> OK Wizards;
>
> I know someone can help me with this issue. It may get your attention off
> of
> crimps and solder (zzzz) for a while. My heater valve (in the hose upfront)
> has vacuum to it all the time. Can't really tell if it is more or less with
> the control set to heater or off. On a previous '73-23',40 years ago
> (really) I researched it and removed the vacuum valve and replaced it with
> a
> ball valve so I could optimize the AC by eliminating any hot water going
> through the core. First question is there an easy repair to the control
> unit
> to actually turn on and off the various valves; 2nd question is there any
> valves that really work; and 3rd question do you see any problems with
> throwing that heater valve away and putting in a ball valve?
>
> Thanks
>
> Dean Hanson 75 Avion- up and raising.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] HVAC controls [message #353387 is a reply to message #353382] |
Tue, 31 March 2020 19:46 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Perhaps inspect the wafer in the control valve and put a light film of plumbers lube on the smooth contact surface. You can take water valve out of hoses snd see if it's working as a test. Theoretically they weep a bit when off so some fresh coolant circulates to the core to replace additive package in the high corrosion areas. . Mine on my 77 works. I like that because in spring and fall it's usually heat in the AM and AC once sun is up and I want control at dash. No vacuum should be On and vacuum should be Off.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] HVAC controls [message #353392 is a reply to message #353382] |
Tue, 31 March 2020 20:04 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Dean,
I can't give you any direct answers, but this link will show you a color
coded version of the vacuum diagram. It may help you to figure out the
problem and get the system working.:
http://www.gmcmhphotos.com/photos/color-hvac-troubleshooting-charts/p22990-hvac-diagram-color-comp.html
As far as the added ball valve, I have one on my '76 and think it helps in
the summer.
Good luck -- you CAN fix it.
Ken H.
On Tue, Mar 31, 2020 at 7:29 PM Hanson Email via Gmclist <
gmclist@list.gmcnet.org> wrote:
> OK Wizards;
>
> I know someone can help me with this issue. It may get your attention off
> of
> crimps and solder (zzzz) for a while. My heater valve (in the hose upfront)
> has vacuum to it all the time. Can't really tell if it is more or less with
> the control set to heater or off. On a previous '73-23',40 years ago
> (really) I researched it and removed the vacuum valve and replaced it with
> a
> ball valve so I could optimize the AC by eliminating any hot water going
> through the core. First question is there an easy repair to the control
> unit
> to actually turn on and off the various valves; 2nd question is there any
> valves that really work; and 3rd question do you see any problems with
> throwing that heater valve away and putting in a ball valve?
>
> Thanks
>
> Dean Hanson 75 Avion- up and raising.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] HVAC controls [message #353455 is a reply to message #353392] |
Thu, 02 April 2020 19:43 |
C Boyd
Messages: 2629
Registered: April 2006
Karma: 18
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Senior Member |
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After trying the sandpaper it did help some but I was still having issues getting enough vacuum to each position when needed. I had a suggestion from another GMCer to change the center clip of the disc assembly to a small bolt and lock nut to put more pressure on the sealing surface and it worked much better.
C. Boyd
76 Crestmont
East Tennessee
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