Two Thermostats to Control a Single Loop System

Wm

Issue: This is a 2-family dwelling (2 floors with one family per floor) with a single loop hot water heating system (one boiler, one circulating pump). There were originally 2 thermostats (one per floor, thermostat wiring still exists for each floor). 1st floor now has a programmable thermostat and the 2nd floor thermostat is disconnected at the boiler control wiring.

I would like to have a functional 2nd floor thermostat to also control the system. Can this be done by adding a 2nd floor thermostat and connecting the thermostat wiring at the boiler control wiring to the same connection points as for the 1st floor thermostat? For this discussion, let's disregard the issue of one or the other floors being heated when it's thermostat is not calling for heat. It's more of the issue of resolving any possible electrical problems associated with two parallel thermostats.

Dale

Just switches

Stats are just switches, so you can put them in parallel. Remember some stats, those that have a heat anticipator are also little loads, so to keep the amp draw reasonable, assumming a 24V stat, set the heat anticipators down to less than 1/2 an amp.