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Default Position for Vacuum Heat Riser Valve

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Old Apr 22, 2009 | 12:29 AM
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Default Default Position for Vacuum Heat Riser Valve
Is the default position (no vacuum) for a 70's-80's vacuum-actuated
heat riser valve open or closed?

Thanks,
Ken R.

.
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Old Apr 22, 2009 | 12:46 AM
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C3 of Year Finalist (appearance mods) 2019
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Open= as the vacuum is applied it pulls the rod and closes the valve
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Old Apr 22, 2009 | 01:15 AM
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Defaulting to open is a safe design.

Thank you.

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Old May 16, 2009 | 11:40 PM
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So the vacuum source for the heat riser PULLS vacuum when the car is cold and STOPS vacuum when the car warms up?

Not only that; but it has to release the vacuum already applied to allow the heat riser to open?
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