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View Full Version : Dash Heat - is there a hot water valve?


Northof49
08-02-2016, 08:25 PM
I have a 2000 Tourmaster - 40 ft with 450 Cummings engine.
The dash heater has never worked since purchasing it 3 years ago.
Air blows nice and cold.
Some 18 wheeler trucker friends advised their units have a water valve shut off to their dash heaters that can turn having dash heat off in summer & on in winter. We looked everywhere from rear engine compartment to front area above where the gen-set comes out - no valve.
Can anyone throw some light on this?
If there is no valve - what else could it be?

Mike
North of the 49th Parallel

RayChez1
08-02-2016, 10:49 PM
Not sure, but there has to be some kind of a vacuum valve that will direct the flow from regular vent air to heater warm air. Some of those valves are manufactured by Evans. Should be under the dash or on the outside of the firewall.

I think that would be the first thing I would look for.

richardscatzhouse
08-05-2016, 12:38 PM
The hot water valve is in the front next to the heater block, I recently came across a great way to test. before you warm the motor set the temp to full cool! then as the motor warms 100deg or better use a thermometer, I recently got a cheap laser model $30 and check the hose temperature on each side. on the incoming side it will be warm on the side entering the heater it will be cooler, verify by turning the heater control on to full till both sides of the valve balance, then return the setting to full A/C if the valve is working you will be able to see the temp drop on the block side while on the other side the temp will stay hot! I find this a great savings. $30 for a laser temp gauge available at most hardware stores. or a $150 service call at a shop.

cabinhill
09-27-2016, 05:20 PM
my valve is under the bed right on top of the motor

richardscatzhouse
10-05-2016, 02:42 PM
Really separate from the motor? Sounds to me like your talking about the motors thermostat, which is usually attached to the water pump housing. Mine is in the nose just below the windshield line.