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I have a question on wiring the sr 503. Boiler is weil mclain 3 section oil with tankless coil 3 zones of heat domestic is still from the coil installed new relay sr 503 so circ wouldnt run below low limit wired to diagram in taco wiring diagram dated 2005 circs will still run below low limit if I remove wire from zr terminal it works right but then wont fire burner to limit called taco tech suport they told me it should work and that I had a wire wrong or a jumper left in went back and rechecked all wiring and it is per diagram and there is only one feed wire to boiler boiler had 2 sr 501 but werent wired through zc and zr originally any help would be greatly appreciated