Is this right? One heat zone (thermostat) seems to govern the other three

mikestorm5 · 11-11-2012, 09:58 AM

I have a four zone heat system with a Burnham gas forced hot water boiler to baseboard radiators. I can't get the other three thermostats in my home to call for heat unless the 'main' thermostat (the one that controls heat/cool/fan) in the Master Bedroom calls for heat. I have almost no experience with this type of heating system, but that seems to defeat the benefit of multi zone heating as the heat in our master bedroom needs to be on if we want heat in the living room, office, or guest rooms.

All four thermostats are Honeywell dials. One of the 'slave' thermostats is simply R/W two wire and green wire was capped off. Haven't checked the 'master' thermostat yet.

I discovered this quirk when I upgraded one of the dials to a programmable thermostat. Couldn't get the new stat to call for heat. Thought it was a wiring problem until I noticed I couldn't get the remaining two 'slave' dials to call for heat either unless heat was on in Master bedroom. With heat in MB on, dials and new programmable works.

Is this one of those 'not a bug but a feature' type deals?

hvac instructor · 11-11-2012, 02:41 PM

sounds like someone rewired the control wiring by the zone valves so all come on at the same time so the boiler wont cycle all the time.
you need to check how the wireing is by zone valves.

mikestorm5 · 11-11-2012, 04:08 PM

Thanks for reply. Below is a photo of my zones, which I'm pretty sure doesn't tell you anything. Is there anything else I should photograph? Wires all come from a junction box with the phrase '24 volt system' written on it in sharpie.

hvac instructor · 11-11-2012, 05:59 PM

if all thermostat wires goes into a junction box thats where most likely tied together.
you will need a wire diagram on the zone valve and boiler to correctly have it operate.
I dont know how good you are with electrical control circuit. might need an HVAC tech. look at it.
make sure they know zone valves.
normal operation is when any thermostat calls for heat and zone valve opens the end switch in valve will start the pump.