Circulator wiring with Taco SR504 switching relay

danaturcotte

Hello, let me thank you in advance for your information and time. This is my first post so bare with me. I have a unconventional out door wood boiler with radiant heat. 3 zones for house and one zone for pool. My question is it possible to have the circulator at the wood boiler only come on if one or multiple zones circulators come on from the thermostat for such zone? If so how would I wire it to do so using a taco sr504 switching relay? Reason why I'm asking is I have a main cir. on a large diameter loop from the wood boiler into the house that circulates 24/7 then the zone circulators branch off of that loop I would like it to only circulate when a zone or multiple zones call for heat

Dave H_2

You cannot make it work with the exisitng control you have. You do need to add either a single zone relay (SR501) or a newer SR504-exp.

Using the existing and a new 501, you would wire 120v and the boiler pump to it.

From the the relay you already have, 2-wire t-stat wire would run from the bottom right terminal (isolated end switch) to TT at the top of the SR501.

If you were to get the new SR504-exp, it would have the terminal for Primary Pump and its function is already in the controller.

danaturcotte

Thank you Dave H_2 , I appreciate the information. I will look into the SR504-exp

bjohnhy

I don't remember details, but I've come across a system where the main system circulator (like you describe) is fed with the 120vac hot wire going through this isolated end switch. That switch closes when any one of the zones call.

Was that not an appropriate set up?

danaturcotte

That was my thought as well.because the end switch is to turn a boiler on i believe. It should handle powering a circulator I'm just not that knowledgeable in how to wire it. Thanks for your input.

bjohnhy

I don't know the amp and voltage ratings for that isolated end switch. Hopefully someone more knowledgeable chimes in

Joe Mattiello

Nice system. I love you have a zone for the pool too. Are you using a HX?

As for system pump enabled on demand from any of your 4 zones, use the ZR terminal. Leave the factory installed jumper in place, add one leg of your circulator on ZR, and the other to any neutral.

ZR is energized with 120 volts anytime any zone has a demand. It's normally used for a triple aquastat with corresponding ZC/ZR. Hopefully this was helpful, and saved you from a lot of extra wiring and/or buying another control:)

danaturcotte

Oh Thank you so much for your info. It's a huge help. Most of the time I get you have what? You can't do that! Lol. Yes Joe, I have a Bowman 5103 2T Titanium tube and shell. It works great, I use it with a salt chlorine generator pool, 35,000g. In the early spring and late fall. Temp right up to 85° in no time. Thanks again guys I appreciate you.

danaturcotte

Just an update. Using the ZR terminal did the job. So much better than before. I believe I will save a lot on wood this way. Again thanks for everyone's support.