Need some ac/heater help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

hdff · 02-05-2016, 09:35 PM

I just finished going thru my ac and heater. When I bought the ac cab truck the ac wasn't working and the heater core leaked. I refurbished the heater box and core and evaporator. I also put everything back under the hood, compressor,condenser, all of the hoses and hot water valve. Everything is back together except I have NOT filled it with R12 yet.. While driving with the vent on and outside air selected the air comes thru a little warmer than the outside air as to be expected. When I slide the selector to inside air the air gets hot like the heater it on. Does this sound right? When I slide the selector knob the vacuum opens the vent on the kick panel and closes the one under the cowl, and I assume makes the hot water valve move, but why would it open the hot water valve at this point? If I left the top lever on inside and slid the second lever more to the left to ac I would not think I would want the hot water circulating while the compressors is on trying to cool. Do I have something wrong? Am I thinking right? If not that compressor is going to work really hard to cool that hot air.. Any help will be greatly appreciated.. It looks to good not to work right...

snipescastle2 · 02-05-2016, 10:42 PM

I believe the vacuum is applied to the valve normally when the a/c position is off, so that said, when you select a/c, the vacuum is shut off to the water valve. I'm sure someone will chime in with a schematic ( I'm out of town currently, and don't have my computer in front of me) i'll see if I can find one for you online..
Ben

snipescastle2 · 02-05-2016, 10:47 PM

Picture

Andy4639 · 02-06-2016, 08:32 AM

Make sure the hot water valve is operating correctly. I have always installed a manual valve in line to make sure the flow is shut off. Just a little water flow will cause heat in the truck when the AC is on. Mine cut a good 5* off the temperature inside the cab.

hdff · 02-06-2016, 10:28 AM

Quote:

Originally Posted by Andy4639

Make sure the hot water valve is operating correctly. I have always installed a manual valve in line to make sure the flow is shut off. Just a little water flow will cause heat in the truck when the AC is on. Mine cut a good 5* off the temperature inside the cab.

The hot water valve is new, but these days that means nothing...... Where did you get your manual valve, does someone make one specifically for that purpose? I'll do some more checking when I get a chance. As I recall both sides of the valve are warm/hot all of the time

Andy4639 · 02-06-2016, 10:48 AM

This is the one I use. I got it at Ace hardware locally several years ago. I have it mounted up close to the fire wall.

http://www.autozone.com/fuel-systems/shut-off-valve

snipescastle2 · 02-06-2016, 11:01 AM

Good info for sure! I know there are two versions of the vacuum control switch (A/C control panel) three ports -vs. two ports,I believe the three port version eliminates the need for a "tee" hope this helps.....
Ben

02-05-2016, 09:35 PM	#1
hdff Registered User Join Date: Apr 2007 Location: pasadena,TEXAS Posts: 880	Need some ac/heater help I just finished going thru my ac and heater. When I bought the ac cab truck the ac wasn't working and the heater core leaked. I refurbished the heater box and core and evaporator. I also put everything back under the hood, compressor,condenser, all of the hoses and hot water valve. Everything is back together except I have NOT filled it with R12 yet.. While driving with the vent on and outside air selected the air comes thru a little warmer than the outside air as to be expected. When I slide the selector to inside air the air gets hot like the heater it on. Does this sound right? When I slide the selector knob the vacuum opens the vent on the kick panel and closes the one under the cowl, and I assume makes the hot water valve move, but why would it open the hot water valve at this point? If I left the top lever on inside and slid the second lever more to the left to ac I would not think I would want the hot water circulating while the compressors is on trying to cool. Do I have something wrong? Am I thinking right? If not that compressor is going to work really hard to cool that hot air.. Any help will be greatly appreciated.. It looks to good not to work right... Attached Images __________________ 1971 Cheyenne SWB 402BB, 700R4, 3.73 posi, PS, PB, A/C, Tilt, Tach "Wanda" Don't argue with idiots, People watching may not be able to tell the difference... There's someone in my head........But it's not me...... cheap tricks thread great info here!! http://67-72chevytrucks.com/vboard/s...d.php?t=489394

02-05-2016, 10:42 PM	#2
snipescastle2 Registered User Join Date: Mar 2009 Location: WARRENSBURG,MISSOURI,64093 Posts: 1,518	Re: Need some ac/heater help I believe the vacuum is applied to the valve normally when the a/c position is off, so that said, when you select a/c, the vacuum is shut off to the water valve. I'm sure someone will chime in with a schematic ( I'm out of town currently, and don't have my computer in front of me) i'll see if I can find one for you online.. Ben

02-05-2016, 10:47 PM	#3
snipescastle2 Registered User Join Date: Mar 2009 Location: WARRENSBURG,MISSOURI,64093 Posts: 1,518	Re: Need some ac/heater help Picture Attached Images

02-06-2016, 08:32 AM	#4
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Need some ac/heater help Make sure the hot water valve is operating correctly. I have always installed a manual valve in line to make sure the flow is shut off. Just a little water flow will cause heat in the truck when the AC is on. Mine cut a good 5* off the temperature inside the cab. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

02-06-2016, 10:48 AM	#6
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Need some ac/heater help This is the one I use. I got it at Ace hardware locally several years ago. I have it mounted up close to the fire wall. http://www.autozone.com/fuel-systems/shut-off-valve __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

02-06-2016, 11:01 AM	#7
snipescastle2 Registered User Join Date: Mar 2009 Location: WARRENSBURG,MISSOURI,64093 Posts: 1,518	Re: Need some ac/heater help Good info for sure! I know there are two versions of the vacuum control switch (A/C control panel) three ports -vs. two ports,I believe the three port version eliminates the need for a "tee" hope this helps..... Ben

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