Heater

[Okiedokie]

What am I overlooking? Southern Rods heat and air unit. Vacuum controled heater valve is being pulled open, vacuum doors in evaporater case are functioning, routing between vents and floor. Radiator is full and pressure heater hose is hot. Going on a fall cruise this weekend and Momma will want some heat early and late. Joe

[kb426]

If you have no water flow, I'd remove the hoses and try reverse flushing in case there's something in the core or in the lines. If the core is higher than the engine, you could have an airlock.

[wayne petty]

also ... do you have a thermostat??

no thermostat  or a stuck open thermostat sends all the water flow through the radiator..

no pressure can build up behind the stat and force water the long way through the heater..

mercedes and i think bmws use an electcric pump to circulate water through the heater core...

[Okiedokie]

Would it make sense that even though the vacuum is pulling the lever on the heater valve open that the valve itself may not be opening? Does not make sense to me. I know water is flowing in the hose because it is hot back to the valve. I may try taking the valve out of the system tonight.

[enjenjo]

You sure the AC is being shut off?

[Okiedokie]

Yea, pretty sure. When I turned swicth to a/c I could hear the compressor engage and disengage when back to heat. I guess if I disconnect the hot iwre to the a/c compressor I will know for sure. Thanks, Joe

[chopped]

The heat is all the way to the left if you have the knob type of control like me. Thought I had the same problem until I checked.

[Okiedokie]

Thanks, I did remember to make that adjustment. the more I think about it, I believe it has to be the valve in the heater hose. Thanks for the tips. Joe

[wayne petty]

one last thought... some heater valves open with vacuum some close with vacuum...

[Okiedokie]

Wayne, you correct, the t-stat was open. Relaced, now have heat. Thanks, Joe.