Community Forums

DAN L · 09-01-2007, 01:39 AM

VACCUUM LINES SEEM OK. TEMP SELECTOR MAKES HOT AIR WHEN SO SELECTED, BUT AIR IS ALWAYS WARMER, ABOVE AMBIENT WHEN SELECED FULL COLD.

DAN L · 09-01-2007, 01:39 AM

VACCUUM LINES SEEM OK. TEMP SELECTOR MAKES HOT AIR WHEN SO SELECTED, BUT AIR IS ALWAYS WARMER, ABOVE AMBIENT WHEN SELECED FULL COLD.

Oemtech · 09-01-2007, 03:56 AM

Check the heater control valve.... If it is made by Evans Tempcon it probably has gone bad.Common proble. Many folks put a shut off valve in the heater hose that feeds the water heater.

Simba34sbd · 09-01-2007, 08:36 AM

Check under the hood. Look at the fresh air blend door located on the passenger side front. It is at the bottom of the black box and has a silver vacuum motor in the center. The motor controls the two doors just below the vacuum motor. IF the soft grey foam insulation on the doors is bad or mis-fit, or if the vacuum motor is leaking, and the ambient outside air (below the hood) is hotter than the outside ambient air, you will get hotter air in the cabin.
You can duct these air inlets to cooler air or have a hvac buddy make a duct. You can also make sure no heated air from the engine is returning back under the coach and getting into this fresh air inlet for the air conditioning.

Also make sure you do not have a vacuum leak. I would simply run the engine for 5 minutes. Shut it off. Wait for an hour and then, with the temp selector in the max cold position, pull the vacuum line off the silver vacuum motor discussed earlier. If you hear vacuum suction and the air blend door opens, chances are that it is not a vacuum leak.

As OEMTECH stated, the other problem is the leaking hot water heater core control valve.

LeeB · 09-02-2007, 05:40 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by oemtech:
Check the heater control valve.... If it is made by Evans Tempcon it probably has gone bad.Common proble. Many folks put a shut off valve in the heater hose that feeds the water heater. </div></BLOCKQUOTE>

OK I have been reading about putting in the shut off valve for a while now. I don't have that problem (YET) but I would like to install the valve BEFORE I do... Where is the hose located and what kind of valve should I install? Pics are most help full...

Thanks Lee

Oemtech · 09-02-2007, 10:57 AM

Here you go Lee. Just install the shut off valve down stream of the heater control valve.

"007" · 09-02-2007, 04:26 PM

Heres the ball valve I placed in the heater hose to cut off the hot water to heater coil.

Its a 1/2" ball valve and two pieces of 1/2" copper pipe that fits tight into heater hose and a couple of 1" clamps.

Worked great when in Branson this summer in the heat.

LeeB · 09-02-2007, 05:59 PM

Woo Hoo thanks Dale I will check it tomorrow.... Thats not going to have any effect on the Radiator is it?

I am surfing and looking for a RV Shelter (I have found a few) to have built when I move to Tenn next year.. Of course that is if my house sells here... What I really want is a RV Shelter with a Garage attached for the wifes car...

Oemtech · 09-03-2007, 10:33 AM

Nope, water flows from the engine to the heater and back via the water pump.

rick_od · 09-04-2007, 02:17 PM

Dale,
I may be wrong but I thought that the heater core had 2 lines. 1 in and 1 out. If you put a ball valve in one, doesn't the flow through the heater core stop? I know that this will fix the a/c trouble but will doing this in the summer months (which you would be doing if you need the a/c) affect the coolant temps as it effectively reduces the quantity of coolant?
I ask because I am considering doing this to my Motor Aid. Even know the Motor Aid motor may be off, it still radiates heat at the rear of the RV.

rick_od · 09-06-2007, 11:08 AM

come on Dale....I know you have some good info on this

scoutmstr · 09-06-2007, 11:45 AM

The old Chevy P-32 chassis manual had an article by Jay Haynor, respected tech writer, on a shut off valve. It was a H design made by Acme Radiator, Goshen In. It was available to FMCA members for $20. They also made a cable shutoff from dash to valve that was made of cable not wire and never kinked. Installed both on my old P32 years ago and worked fine. Don't know if they are still there or making valve but it reduced the problem with noncirculating water through system while stopping heat transfer.