Zone Heating Issues

Ni24ck

I have a 3 zone system and when one of the zones calls for heat, the other zones also heat as well but the circulator pumps don’t engage. For example...If I turn thermostat on upstairs the hot water flows through both upstairs and downstairs zones and vice versa. I have 2 smart thermostats and they are both wired correctly.

Alan (California Radiant) Forbes

Sounds like phantom flow.

Is this a newly installed system? If so, call the heating contractor back.

Zman

That is usually caused by a lack of check valves on the zones. Pictures would help

Ni24ck

This is my setup

HVACNUT

IFC circs on the return, upside down.
Terrific.
Maybe the check valves were removed.
Take some pics from farther back to show all near boiler piping.

hot_rod

Usually the stickers are placed on the circulators when checks are installed, so the next person knows.

Pumps on the supply, with checks will eliminate any ghost, or thermosiphon flow. Hot water can rise up inside a pipe, cooler water drops around it and caused a slow but steady ghost flow condition. Pumps on the returns don't give you that protection.

DZoro

Has the system ever performed properly?

HVACNUT

> @hot rod said:
> Usually the stickers are placed on the circulators when checks are installed, so the next person knows.
>
The Taco IFC circs come with the IFC sticker affixed to the pump. In the box theres a small black sticker that says "check removed".

Its quite possible they were removed though, but I doubt it.