One thermostat controlling both zones

jdanyc

I have 2 zones of baseboard heat but only one thermostat is now controlling both floors. Zone valve controller is Taco ZVC403 and valves are Honeywell V8043E1012. Ideas for how to troubleshoot?

EBEBRATT-Ed

Do you have a thermostat for each zone? If only one thermostat is controlling the other zone valve could be stuck open.

Big Ed_4

I assume one of the floors was an Appartment at one time. . Every floor or addition should be zoned for comfort. Each would have a different Heat Loss .. I would recommend another thermostat for the other zone ...Troublesohoot ?

jdanyc

There are 2 thermostats, one for upstairs and one downstairs in a home. All was working properly until last week.

jdanyc

If one valve is stuck open how could I get it to close? Or does it need replacing?

Big Ed_4

If stuck open with no power to valve try some WD40 .. You can feel if the lever is loose it will be open .. If not loose and still bypassing you need to change the guts if the valve ..Inside there is a rubber ball on a lever . Sometimes the ball will split .

jdanyc

Thanks Big Ed. The lever is loose. Not sure where to try WD40

HVACNUT

The lever should not move freely unless the valve is powered open. If the thermostat is off, the lever should have tension to push open manually.
There are 2 yellows. Remove one of them from the board terminal and see if the zone valve closes.
There might be a short in the relay in the board for that zone.
Looks like there's a spare zone in the board. Try swapping over.

EBEBRATT-Ed

If the valve has no power it is likely stuck open