3 posts / 0 new
Last post
Forced Hot Water Issue

I have a 4 zone forced hot water system. One of the zones has hot water circulating through it constantly, although the circulator pump is off. The other three zones do not. What could be causing this? I had to shut the valves for that zone because the temperature was approaching 80 degrees.

Re: Forced Hot Water Issue

The flow control valve in the over-heating zone is probably stuck open, causing the hot water to flow when any of the other zones are circulating hot water (known as ghost flow).

Each one of your circulator zones also has a FLOW CONTROL VALVE (flo-chek) that opens with the force of the pumped water when that zone is calling for heat, and CLOSES automatically when that zone is NOT calling for heat.

The flow control valve is usually located immediately downstream of the circulator for that zone, and usually has a small metal tag on it that identifies the valve.

Quite often a flo-chek gets stuck open when a piece of crud accululates inside the valve that prevents it from opening and closing normally.

There is a small knob or tab at the top of the valve that you can manually twist several times clockwise to close, and turn counterclockwise to open to release the crud buildup and allow the valve to operate normally.

You may have to manually open & close the valve a number of times before you restore its ability to operate on its own, as it should.

In the end, the valve has to be left in the CLOSED position to prevent the zone from over-heating.

Google "flow-control valve" or "flo-chek" valve for sites that describe this valve.

Post back if you continue to have problems getting normal operation.


Re: Forced Hot Water Issue

Thank You. I have located the flow check valves and opened and closed them several times. I then left them in the closed position, as instructed. I will know within a few hours if this fixed the problem. Thanj You so much for the sdvice and help.

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.