View Full Version : Wiring Taco SR 504 to start two pumps

11-04-2007, 06:29 PM
A bit of background; This is a new installation. The setup as described is what I currently have, with the exception of the wiring.

-Bock oil-fired water heater supplying DHW and in-floor radiant heat. The water from the heater is circulated through a flat-plate heat exchanger by a Taco 006 bronze circulator for the radiant zones.
-Taco SR 504 with two zones in use, each controlling a Taco 00R circulator.
-I'd like when either zone calls for heat and the zone circulator kicks on, for the bronze circulator on the water heater to also come on :confused:
-As the water heater gives up its heat via the heat exchanger (or for DHW uses), the aquastat will control the boiler lighting off.

My problem comes with the wiring of the switching relay and the bronze circulator on the water heater. The Taco documentation is pretty thin as far as I've found. I've found reference to powering the aquastat to fire the boiler whenever a zone calls for heat, but nothing for a second pump. The answer seems to be somewhere in the "isolated end switch" and the strategic placement of a jumper. So far, the only way I've been able to get 120v to the isolated end switch would leave my second circulator on 100% of the time. I'm hoping this is straightforward and I'm missing something really obvious.

Thanks in advance for any guidance!