Chassis heat won't return

[Mick Morgan]

Hi from Uk
It's cold here now, just taken rv for yearly service and test, I had cold feet for the 3 hour drive, last driven with the chassis heat on cool position, now won't return to heat, all 3 fans working as they should but clearly the hot water is not reaching the heater matrix, hydronic heating working on primus fine, so I'm assuming it's a problem at the font of the coach, the temp adjustment slide control feels like it's doing something as there's a slight click half way along, I would like warm feet on the way back home, so any help greatly appreciated
Kindest regards
Mick
1994wb40

[chiplamb]

Is your Summer/Winter switch in the Winter position? May just be that simple. That or turn your Aux Pump on if it has a separate switch.
Cheers

[atckip]

Check that the cut off valves haven't been closed in the engine compartment also

[isp2952]

Originally Posted by Mick Morgan

Hi from Uk
It's cold here now, just taken rv for yearly service and test, I had cold feet for the 3 hour drive, last driven with the chassis heat on cool position, now won't return to heat, all 3 fans working as they should but clearly the hot water is not reaching the heater matrix, hydronic heating working on primus fine, so I'm assuming it's a problem at the font of the coach, the temp adjustment slide control feels like it's doing something as there's a slight click half way along, I would like warm feet on the way back home, so any help greatly appreciated
Kindest regards
Mick
1994wb40

Could be a couple of things on the chassis heat. Go back to the engine bay and find a couple of gates valves. They should be located between the black hydraulic cylinder and the engine. One is very obvious the other is kind of hidden and you will have to look for it. Open them up to allow heated coolant to the front heat. Another thing if that doesn't work, open the breast plate on the front of the bus. On the passenger side, you will see the heater core with a line to it. There should be a petcock located in there somewhere. Start the bus up and turn on the chassis heat. Then open that petcock to expel any possible air lock that may have occurred.

[Mick Morgan]

Thanks all, it seems it's the issue is the valve at the front not letting hot water in

[Spowell75]

I am working on a 86pt40 and cant find the petcock on that heater core. where else might it might bee?
thanks Dave

[Mick Morgan]

Problem found, in front of passenger side front wheel is an electronically operated valve to regulate water flow to heater matrix, it's a BMW E24 part, an absolute nightmare to change, easy to get here in uk, about 1 tenth of the price in the states