gas boiler wiring

[pmoney44]

I am about to wire a gas boiler with honeywell aquastat and
A 2/3 zone taco switching relay I understand thermostat wiring ,circulator wiring and feed..my question is there are terminals that on taco wiring diagram about 2 wires going to aquastat. I can not figure out why needed and which terminals are used. Also was wondering if a thermal cutoff switch is needed above the gas boiler..thanks in advance

 

[ActionDave]

The connection for the aquastat is probably there to make the call for domestic hot water a priority and close all other zone valves.

 

[stickboy1375]

. Also was wondering if a thermal cutoff switch is needed above the gas boiler..thanks in advance

No... not required.

 

[stickboy1375]

I am about to wire a gas boiler with honeywell aquastat and
A 2/3 zone taco switching relay I understand thermostat wiring ,circulator wiring and feed..my question is there are terminals that on taco wiring diagram about 2 wires going to aquastat. I can not figure out why needed and which terminals are used.

You generally only need an endswitch off the TACO control to fire the boiler... but without seeing what you have.... read the manual when in doubt...

Is the domestic hot water a tankless or a storage tank?

 

[goldstar]

You have to look at the diagram inside the cover of the aqua-stat. It will show you the terminals that the T-stat gets connected to. As far as the boiler mfr. is concerned there is only one t-stat. It doesn't make a difference whether you connect 1 t-stat or 20. As long as you close the contacts between the terminals shown the boiler will turn on. As was previously mentioned, all the n/o end switches get connected in parallel. Any t-stat that calls for heat will close its respective end switch and thus turn on the boiler.

BTW, you'll have to be careful how many t-stat motors you run off the power provided by the aqua-stat. Some will limit you to 2. In larger systems I usually install one separate 40va xfmr for every 3 t-stats.

You may also have to wire in a low water cut-off. That will require a 24vac feed and a pair of wires in series with the pair of wires that activates the aqua-stat. Hope this helps.

 

[stickboy1375]

You may also have to wire in a low water cut-off. That will require a 24vac feed and a pair of wires in series with the pair of wires that activates the aqua-stat. Hope this helps.

Not necessarily, BUT.... you're either breaker 120v, or 24v to the boiler... not a real issue in my eyes.

 

[goldstar]

Not necessarily, BUT.... you're either breaker 120v, or 24v to the boiler... not a real issue in my eyes.

True. If the low water cut-off operates on 120VAC then you wire to that first and break the feed to the boiler. If it operates on 24VAC you can use T-stat cable and break the wiring that activates the aqua-stat.