Wiring Grundfos single zone relay, pump, and Rinnai E50C boiler

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Ed Dooley

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Finally found the time to finish the boiler installation, and I'm having a brain freeze. I have some of the wiring done, but the installation instructions that comes with the relay (and to a lesser extent, the boiler) leave a lot to be desired for an amateur. It's a single-zone system with one thermostat. So, here's a list of questions (be gentle!):
- I'm running the 120v power for the pump (and by extension, the relay) and the boiler through one switch so everything gets shut off together for repair, maintenance, or emergency. Usual practice?
- I'm fine on how to power the pump through the relay, and to connect the 2 wire thermostat wire to the relay. But I'm less clear on connecting the relay/pump to the boiler. From the illustrations (attached to this post) it appears the boiler has a separate 120v line in for power, and the relay connects to the boiler (24v TT wiring?). If so, then where on the attached boiler illustration does the wire attach, the thermostat connector?
- I'm also a bit fuzzy on the Rinnai illustration of the external pump connector (green block, 2nd from left in illustration). Maybe I'm so far off-base and the relay actually goes to that Rinnai connector (and therefore is 120V). And to make me even more confused is the note for that green external pump connector warning about not connecting a pump directly because of a call for heat or DHW energizing that circuit.
- Any help?
boilerwiring.jpg
Wiring1.jpg
wiring2.jpg
UPZCP-1 relay.jpeg
Thanks!
 
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