Wiring an Indirect Water Heater to One Heating Zone Oil Boiler and Creating A Priority Zone
Are you tired of buying a two-zone control when you have one zone of heat and an indirect water heater? Here is a straightforward way around that problem. Buy a single-zone relay like a Taco SR501, and you'll have a significantly cheaper control that prioritizes the indirect. You gain indirect priority and save money in the process.
I have seen many jobs with a single zone of heat, using separate circulators and indirect, where they wired in a two-zone control to separate the indirect from the heating thermostat. This wastes money on the control, labor, and wire.
I have included two drawings below. One will show the wiring with a Honeywell L4006A Aquastat on the indirect, and the second will show the wiring with the Vaughn tanks, Velocity Boiler, or US Boiler TPI Control on the indirect. The major difference is that the TPI control requires a constant 24V power supply to the control. The TPI control is used on stone-lined tanks and will avoid overshooting the tank, which the L4006A will not do on the stone-lined tanks.
Indirect with L4006A Aquastat.
Indirect with the Vaughn TPI Control
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