Thrust Flow control Valve Makes Noise

Old 10-28-06, 01:04 PM
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Thrust Flow control Valve Makes Noise

I have a hot water heating system that was converted from a steam system year ago. With the exception of the piping needed to change to install the hot water boiler, all the piping and radiators are the original steam system including the thrust control valves. It is a two zone system using two circulators but one of the zones is split into two circuits, so there are three thrust flow control valves. Everything has run just fine for over 20 years until last heating season when one of the valves started making a terrible rattling sound when the circulator started running. I assume this is the flapper valve fluttering inside the valve body. Is this a typical problem? Can the valve be adjusted to stop this? Does the valve need to be replaced? There appear to be several plugs on the side of the valve but I have no idea where to start on this thing. Do you have some suggestions?
Old 10-28-06, 04:58 PM
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Flow control valve

Chattering flow control valves are usually symptomactic of air in the system. Since the "flapper" can't be supported by air, whenever air passes thru the valve, the flapper falls & then pops back up, falls, opens, etc. creating the chatter. If you have the valves I think you do, there are indents on the side & marked "open", "normal", & "closed". The lever on the side has a bolt or screw which when screwed in will go into one of the indents.

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