Dash Heat Won't shut off

[Homeless Vagabonds]

We have a 2000 38 DSDP with Freightliner / 300 Cat. Yesterday we fired her up after about a 2 month shutdown. The dash heat would not shut off. The temp seemed to be on high and the temp adjustment would not work. The air control was on Vent. Changing the control to Air Conditioner did not change the temp. Luckily the ambient temp was only 70. I have vacuum to one of the baffle activators that moves when I change from Vent to Air Conditioner. Need some help finding the cause.

[Homeless Vagabonds]

We have a 2000 38 DSDP with Freightliner / 300 Cat. Yesterday we fired her up after about a 2 month shutdown. The dash heat would not shut off. The temp seemed to be on high and the temp adjustment would not work. The air control was on Vent. Changing the control to Air Conditioner did not change the temp. Luckily the ambient temp was only 70. I have vacuum to one of the baffle activators that moves when I change from Vent to Air Conditioner. Need some help finding the cause.

[RVDude]

The hot coolant shut off valve has stuck open, a typical and simple problem. It's what's attached to the "temp" control of the heater controls. Do a search on these forums for pictures and fix...

[Norm Payne]

Your Evans control valve is stuck. Some people have had success cleaning and blowing them out, but it is best to replace it. This is a common problem.

[tmitchell]

I have had my Evans Control Valve replaced twice, in the 3 years my MH was under warranty. Last time I had the valve replaced(about 2 years ago) when I got home, I spliced a shut off valve into the heater hose. Now I no longer get warm air mixed into the dash airconditoning, regardless of the condition of the Evans Control (cheap plastic) Valve. I live in Florida, so it is rare that I use the dash heater. When and if I do need it, it will only require opening the front hood and turning the valve to the open position.
When I was having problems, if I turned the temperature control valve all the way to hot wait a few seconds then turn it all the way to cold (usually just once, sometimes two or three times) it would turn off the dash heat, sometimes for 1/2 hour sometimes for several hours.
The tech at my dealership said the valve is a lot more likely to work/move while the engine is at idle speed, rather then at highway speed. He said at idle there is less water pressure against the valve.
Good luck,
Tom

[BZam]

Been there also. You need to change that Evans Control which is not hard to do. Also, when you do get the kit to install a filter just in front of the Evans unit and that will prevent future oceurrances.

If you crawl under your chassis you will probably find a couple of valves where you can shut off all the coolant coming forward. These are in front of radiator around the real axle area. They are just old fashioned garden type valves. I just shut mine off for several months until I got around to ordering the Evans Unit. Log onto the Evans site and it has all the details about this valve and the filter kit.


<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Homeless Vagabonds:
We have a 2000 38 DSDP with Freightliner / 300 Cat. Yesterday we fired her up after about a 2 month shutdown. The dash heat would not shut off. The temp seemed to be on high and the temp adjustment would not work. The air control was on Vent. Changing the control to Air Conditioner did not change the temp. Luckily the ambient temp was only 70. I have vacuum to one of the baffle activators that moves when I change from Vent to Air Conditioner. Need some help finding the cause. </div></BLOCKQUOTE>

["007"]

Homeless here is a pic of what they are talking about. Ball valve

[tmitchell]

I installed a brass flush kit, by splicing it into the heater hose. I cut through the heater hose and hose clamped a brass male (water hose type fitting) to one end of the splice and a brass female fitting on the other end. You connect a hose to the female fitting to flush the coolant system and another hose to the male to route the fluid to a catch pan. Then you screw both fittings together for normal heater hose operation.
I guess mostly by luck the brass shut off valve I installed happened to have a male garden hose type connection at one end and a female at the other. I unscrewed the flush kit and screwed the shut off valve in the middle of it.
I have a picture, but don't know how to post it on this site.

Tom

[CSX4350]

With all of the problems I read about this Evans control valve, I want to install a manual shut off before I have a problem. Is this the valve in question?:



Is it best to install a shut off before or after the valve? What size is the hose?

TIA

[BZam]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by CSX4350:
With all of the problems I read about this Evans control valve, I want to install a manual shut off before I have a problem. Is this the valve in question?:

</div></BLOCKQUOTE>

Like I said in my post, there are probably shut off valves back there at the hoses in front of the radiator. That is the place to have them because you could all have damage and leaks all along your chassis up the front and back.

I know of no case where Newmar or a dealer ever explained they put these shutoff valves in! I just happened to find out on Newmar Yahoo group .
Also, in this photo you need to put that simple filter just in front of the EVans valve. Some buy it from Evans and others just get a generic filter unit.

[Homeless Vagabonds]

Thanks all for all of the good info. This is what makes this forum so great. I have been off "Air" for a few days and just found all of the responses. Ironically, the problem didn't exist the next day, but I will be checking out the "Evans" valve.