i have completed most of the connections to the boiler expect for Zone values, Thermostat and low pressure monitoring.

i need help with understanding if i need to purchase a 24v transformer ? and how to serial connect the wiring with regard to zones valves, thermostat and low pressure monitoring.

  • Do you have a zone controller? What is the make and model of the zone valves? – Tester101 Aug 4 '15 at 10:19
  • I don't have a zone controller installed as it was not required. the model zone valves are Honeywell V8043E1012 – leka Aug 5 '15 at 21:29

First things first, you'll need a transformer to step power down from 120 volts to 24 volts. Next, you'll obviously need a zone valve. You'll also need a thermostat, to actually determine when the heat should come on. You'll need a thermostat and zone valve for each zone, but a transformer should be able to supply a few zones.

Start by connecting one of the yellow leads from all the zone valves, to one of the leads from the transformer. Next connect a wire from the R terminal of each thermostat, to the other transformer lead. Connect the other yellow lead from each zone valve, to the W terminal of the corresponding thermostats.

Gather up one of the red leads from each of the zone valves, and connect them to one of the Heating T-Stat terminals in the boiler (using a pigtail is the proper way to do this, as you're only allowed one wire under screw terminals. Gather up all the other red leads from the zone valves, and connect them to the other Heating T-Stat terminal in the boiler.

example zone valve wiring
Example wiring for a single zone

That's it. Now when a thermostat calls for heat, it will open the appropriate valve, and signal the boiler.

  • thank you so much... just one last thing, does it matter which red is connected to the T stat are they interchangeable ? .... Also I have a safguard low water cut off.. Model 1100... would this come off the same low voltage transformer ? – leka Aug 7 '15 at 12:37
  • There should be two red wires coming out of the zone valves, and two Heating T-Stat terminals in the boiler. So each red wire will go to one of the Heating T-Stat terminals. According to the Manufacturer's installation instructions, there should be a special cable that connects the low water cut off to the boiler (see page 56). – Tester101 Aug 7 '15 at 13:38

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