Unwanted Heat

MikeT99

I'm no plumber or heating expert, so here's my problem: In short, when I run the hot water in my house, the hot water baseboard heat comes on...even after the thermostat has been disabled and the zone valve replaced. The problem is detailed in the attached schematic.

Any help would be appreciated!

MikeT99

Steamhead

I agree- it's circulating thru that loop. To fix it, I'd put in a second zone valve so that each first floor loop has its own. This would be a good opportunity to add a second thermostat so each half of the first floor is controlled separately.

MikeT99

Many thanks Hatterasguy. Okay, I can see and confirm that both legs of the first floor loop return via the zone valve as diagrammed. Next, I am testing your theory about First Floor North also getting hot if the hot water demand runs long enough. I can understand why this might happen. If this turns out to be the case, would this be an "unintended convection loop" or gravity loop?

A "simple check valve"...would you be able to provide me with an example?

If the check valve were installed to prevent backflow in First Floor North, would the problem occur further down the line, in the basement loop?

Very helpful. Thank you.

MikeT99

Thank you Hatterasguy and Steamhead. You are both spot-on. As you suspected, the North Side of the loop did start throwing heat with extended hot water demand, so there definitely is an unintended convection loop (and now its awfully hot up here!).

Knowing that I would have to re-position the current zone valve in order to follow Steamhead's advice, giving positive control to each side of the loop, does it matter where I install these two zone valves, meaning supply side or return side? I'm thing that it doesn't.

Thanks again,

MikeT99

Steamhead

Probably doesn't make much difference. But I like to keep everything the same pattern, so I'd put them on the return side. Much less confusing for the next person to work on it.

Tom_133

I would like to confirm they changed the entire zone valve and not just the head.