heater control valve vacuum pressure

[kapejo]

Can anyone tell me how much vacuum is needed to operate the heater control valve.

Thanks,
- John

 

[Yadkin]

A simple lever valve that size shouldn't take any more than one pound of force to operate (probably a lot less). The diameter of the vacuum cylinder is about 1-1/8", meaning that it is about 1 square inch area. So 1 pound divided by 1 square inch = 1 pounds per square inch. That equals about 2 inches of Mercury (in Hg), which is the common unit to measure vacuum.

So the valve should open under 2 inches of vacuum. Your engine, at idle, should generate at least 15.