Workhorse cab heater not working.

[edsperfect]

MH sat in fl for 5 years and cab heat never used. Now it doesn't blow warm air. I assume it is under the dash behind the metal box with teo hoses running into it. Top hose gets warm bottom no. Therefore i have concluded the heating coil is clogged and will put in some stuff and then try to blow it out in reverse manner with garden hose.

Am I correct in my assumptions here?

[edgray]

Originally Posted by edsperfect

MH sat in fl for 5 years and cab heat never used. Now it doesn't blow warm air. I assume it is under the dash behind the metal box with teo hoses running into it. Top hose gets warm bottom no. Therefore i have concluded the heating coil is clogged and will put in some stuff and then try to blow it out in reverse manner with garden hose.

Am I correct in my assumptions here?

Depending on which heater/AC brand your COACH builder used, there should be a heater control valve somewhere in one of the two hoses going to the "box". This valve is either vacuum or electric solenoid operated from the dash control. It is likely that the valve is not fully open if you are not getting heat. However, it is also possible that a PO added a manual shut-off valve to completely STOP the flow of hot water because he wanted max cooling from the AC side of the "box".

I would first make sure there isn't a manual valve, and then see if I could operate the system valve to increase the flow. If all that fails, then I would be inclined to agree with your diagnosis of a plugged heater core.

["007"]

If you have the Evans AC/Heater unit look at item 34 in this link may solve your problem.
READ THE WHOLE LINK FOR OTHER LINKS.

[edsperfect]

NO manual I can find. The top hose going into the "box" is warm past the sel bottom is cold so i am assuming the heater coild is blocked

["007"]

Link 34

Evans AC/Heater unit

Evans wiring controls

Evans service parts

CHECK THE VALVE

[edsperfect]

oh thanks for this link i will save it

[DD788Snipe]

Replace the vacuum line from the firewall to the heater valve It's blue if I remember it right. Those plastic lines deteriorates and then the valve won't open and the A/C won't work. I've done that on three friends coaches and it fixed it.

[Duner]

Originally Posted by DD788Snipe

Replace the vacuum line from the firewall to the heater valve It's blue if I remember it right. Those plastic lines deteriorates and then the valve won't open and the A/C won't work. I've done that on three friends coaches and it fixed it.

X2 ......The plastic lines deteriorate. My blue line was shot and all I got got was a/c cooling coming down at my feet.