TAC thermostat (model 31-100) for Normally-open zone valve
My condo has a central boiler on top of the 12-storey building that feeds hot water to baseboard heater in each unit. There is a room thermostat that operates a zone valve to control the flow of hot water hence the heat. Few months back the heat in my apartment was on all the time regardless of the thermostat setting. A repair guy sent by the building superintendent replaced the old parts with a TAC normally-open zone valve, a TAC modulating valve, and a TAC thermostat. After the repair, when I turned the thermostat to high, the heat would turn off (the zone valve closed); when I turned the thermostat to low, the heat would turn on (the zone valve opened). The repair guy and the superintendent refused to correct the situation saying that the heat can now be turned “on” and “off”. Anyway, it seems to me that if I switch the wire in the thermostat from the “W” terminal to the “Y” terminal, my heating system would be working properly. The TAC thermostat is 24 Vac and has 3 terminals labelled “Y”, “R” and “W”. Right now there is a single wire each connected to the “R” and the “W” terminals. Please let me know if I am right. Thanks. I'm unfamiliar with this system. However, your logic makes sense to me. Originally Posted by hvactechfw I'm unfamiliar with this system. However, your logic makes sense to me. Thanks. I am also thinking what is the difference between this set up and using a heat only reverse acting thermostat. correct that would be the same concept as using the Y terminal on your current stat. The current stat is a SPDT stat. Choosing Y is is just opening the circuit on temp drop instead of closing the circuit. Originally Posted by hvactechfw correct that would be the same concept as using the Y terminal on your current stat. The current stat is a SPDT stat. Choosing Y is is just opening the circuit on temp drop instead of closing the circuit. so are you saying that it is the same as using a heat only reverse acting thermostat? yes. that is exactly what I'm saying. Originally Posted by hvactechfw yes. that is exactly what I'm saying. Thanks. I will test it out and see. The only thing I am wondering is why then they want to make a heat only reverse acting thermostat, if we can do without by doing it my way. From the web, I can see that the 2 are more or less the same price. because your thermostat is meant for heating or cooling. But it uses the same concept as heat only reverse acting. yours is heat only or cool only (heat only reverse acting) Originally Posted by hvactechfw because your thermostat is meant for heating or cooling. But it uses the same concept as heat only reverse acting. yours is heat only or cool only (heat only reverse acting) Thanks for all your info.
Related Posts:
Taco zone valve problem
Taco Zone Valve ProblemI have a 3 wire Taco zone valve and I'm not getting heat on that zone. The t stat is a new Honeywell type that looks like the old round ones but has no mercury switch in it....
Taco zone valve wiring
Taco zone valve wiringFirst post, new to the forums. Im trying to add two Taco 571 zone valves to my baseboard hot water system. My set up is this: a Slant/fin Sentry 105K BTU gas fired furnace wi...
White rodgers zone valve wiring
White Rodgers zone valve wiringI'm replacing a basic round Honeywell HEATING ONLY t'stat (without any switches) for a hot water system with a programmable digital to save energy. The White Rogers...
Sticking eriehoneywell zone valve
Sticking Erie/Honeywell zone valveI have a 16 year old Infloor radiant heating / DHW system that uses an Erie/Honeywell three way motorized 24 VAC valve to swap the boiler output between the radia...
Wireless thermostat
Wireless Thermostat?Hello all, new to the forum, first post, so bear with me... I checked some other posts and couldn't my find exact answer, sorry if it is already there. So I think I want a wire...
