Fast fill not holding pressure

Old 12-22-05, 11:42 AM
Bob Schwartz
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Fast fill not holding pressure

I had air in my three zone system, and was able to get rid of the water fall sounds by doing the following: 1) I turned the screw in on the top of the fast fill valve all the way in to create positive water pressure. 2) I turned the zone valves on one at a time to get the circulator going. 3) I shut the butterfly valve on the return. 4) I connected a hose to each zone, and the air seemed to be forced out. The problem is that when I turned the fast fill valve screw out the pressure kept increasing. I am able to control the pressure by letting some water out of the boiler, but it keeps increasing (5 psi per hour). Does this mean that I may have damaged the fast fill by turning the screw in too much? What would be an approximate cost for replacement? To keep the pressure stabilized I had to turn off the valve in series with the input. Is there a danger in not having the fast fill working? I believe the correct working pressure is about 18 psi (max 30). Why is it bad to add fresh water to the system?
Old 12-22-05, 03:39 PM
KField's Avatar
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Location: Easton, PA
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A new auto feed valve should not cost more than around $30. It is probably stuck in the open position. It was probably stuck closed before. The air may have come from your expansion tank so you should watch pressure closely for the next few days. Fresh water contains oxygen and that causes corrosion.


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