Heater control valve position

[N2BUICK]

I remember a thread about this but can't locate it. Is the heater control valve supposed to be open while not on the car? I have an unknown, metal control valve that is open without vacuum.
I am doubting this as the heater flow would be continuous without vacuum source?
Which way are the turbo cars heater valves designed to operate?

 

[Anthony P]

Hi Austin, on the turbo regals, the heater valve is normally open, that is it needs vacuum to close.

 

[N2BUICK]

That is what I was seeing with the unknown valve I have to install.
Thanks for the verification Anthony.

 

[earlbrown]

I am doubting this as the heater flow would be continuous without vacuum source?
Which way are the turbo cars heater valves designed to operate?

Yes. That way if there's a failure, you'll still have a heated defroster in the winter by default.