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jtauriello 09-30-2012 08:49 AM

Set up indirect water heater using Honeywell L7224/L7248
I have an older cold start Weil McLain oil fired boiler with a newer L7224/L7248 controller (the old controller died 2-3 years ago). Until recently I ran a separate oil fired Bock water water heater, but it is nearing the end of its life and I decided to set up an indirect water heater to save on oil and burner maintenance costs. My boiler system is set up with a single circulator pump. I have a spare zone that I plan to hook up to the indirect tank, which originally went to a basement heating zone that I never used. Think it will work if I simply just hook up the thermostat wires to the aquastat on the indirect tank, however, I would like to set up the indirect water heater zone such that it is prioritized over the other 4 house heating zones if possible. I see that there is a ZR terminal on the L7224/L7248 controller, but I am not quite understanding how to wire the indirect tank zone such that it will be prioritized. Would appreciate some advice.:huh:

hvactech126 09-30-2012 09:14 AM

a line voltage aquastat will be necessary that will send L1 power through to the ZR terminal with a demand for heat on the dhw zone. You have to go into the settings of the new L7224/L7248 to setup the priority on the ZR circuit.

see more here: pdf file

page 8 for a schematic
page 5 for adjusting control settings

You should install a separate circulator for the dhw zone.

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