Heater Control Valve function

Hi there from Germany,

I have just removed my heater from under the dashboard, overhauled everything, painted it and replaced the heater control valve. To make sure it's not leaking I then connected the inlet to a garden hose and the outlet with a pressure gauge to make sure that the water pressure doesn't exceed 1.0 bar. No matter if I open the valve or close it, water is still passing through the heater with only a little difference in the flow rate.

When I do the test with air by blowing the air into the inlet with my mouth, the valve works fine. When closed, no air passes through the valve, when open, the air passes freely. So there should be no crack in the diaphragm.


Now I would like to know if the following considerations are correct:
a) The diaphragm, which is located inside the valve and ensures that no water can flow through the valve when closed, is - as far as I remember - somehow spring-loaded and could
therefore have a bypass function???
b) Perhaps design related some water should always flow through the heater so that it does not become muddy and water bubbles cannot form???
c) Third possibility: The Heater Control Valve is defective? But it's new and not leaking?!

Would be happy to hear from you!

Lutz

1 bar hose pressure is probably overwhelming the rubber diaphragm. Remember the system uses 7 psi - 1/2 bar.

steveg said:

1 bar hose pressure is probably overwhelming the rubber diaphragm. Remember the system uses 7 psi - 1/2 bar.

Click to expand...

Steve, I believe you are right. 1.0 bar might have been to much. Breathing out with pressure creates about 0.25 bar, which seems not enough to overcome the diaphragm of the valve.