can i run 2 heating thermostat off 1 boiler in a series like a chain

mike jones_2

can i run 2 heating thermostat off 1 boiler in a series like a chain

Viess

Maybe.

Depends, if its a mono flow setup, yes. 

Jamie Hall

Depends

on what you want to accomplish -- and on the thermostat.  You can control a single heating system element (burner, pump, what have you) with more than one thermostat.  However, you have to think about what you want them to do to figure out how to wire them.



If you want to set it up so the heat comes on when either thermostat A or thermostat B calls for heat, then you wire them in parallel: control to red to red, white to white to control.  If you want it set up so that heat comes on only when both thermostat A and thermostat B calls for heat, then you can wire ordinary two wire thermostats in series: control to A red to A white to B red, B white to control.  If you do wire them in series, you may get some rather bizarre behaviour of the anticipators, and you can't do that at all with some types of power stealing thermostats.

mike jones_2

run-2-heating-thermostat-off-1-boiler-in-a-series-like-a-chain

thanks! we want to run them in series so both events must occur. 



can this be a chain using our existing 2 wire run or will we need to snake more thermostat wires?



also, should we just use your basic honewell wall therm?

MikeT_Swampeast_MO

No Need for More Wires

As long as you have two wires running from each thermostat location, just connect in series.



e.g.  Red wire from boiler feeds thermostat one, white wire returns.  Connect white return wire from thermostat one to red wire feeding thermostat two and white wire from thermostat two back to the boiler.

mike jones_2

run 2 heating thermostat off 1 boiler in a series like a chain

thanks, that sounds pretty logical, almost like 2 light switches.



i think u are saying, put the red on the first thermostat and, instead of putting the white return on that first therm, continue the red from the 2nd (white) wire of that thermostat and continue it to the next zone to hook it to the red on the second therm.. then take the white wire on the second therm and return it all the way straight directly back to the boiler on a home run.



we will try this with our basic old fashioned round honeywells, u know, the kind in the living room wall in the 1970's! 



ps. do we have to worry about bizarre behaviour of the anticipators, could that cause any real problems?