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Wiring 3 Circulators To A Single Output Relay - Taco SR504-4

JustinS
JustinS Member Posts: 258
As I wait for someone to install my buffer tank (spring '16), I currently have 2 of my 3 zone circulators wired so that a single thermostat runs them both... this was done by the company who will install my tank

I was thinking that I might want to try a single thermostat controlling all three circulators - curious to see how this would function in an effort to reduce my short-cycling til the install occurs...

Any reason why this wouldn't be electrically sound?

Thanks

Comments

  • Paul48
    Paul48 Member Posts: 4,469
    Someone from Taco will probably chime in, but you may be better off wiring the t-stat terminals in parallel.
  • JustinS
    JustinS Member Posts: 258
    Paul48 said:

    Someone from Taco will probably chime in, but you may be better off wiring the t-stat terminals in parallel.

    The way it's wired now is that the Neutral from each circulator is connected to the respective N terminal block, the H from the Zone 1 is tied to the Zone 1 H and the H wires from the other two zones are both tied to the Zone 3 H
  • Paul48
    Paul48 Member Posts: 4,469
    @""Joe Mattiello"

    A little help here Joe!!!! LOL
  • dtrani
    dtrani Member Posts: 25
    Speaking from an EE POV and not an installer...

    I have a similar situation where I've got two zones running off of the same thermostat, for the same reason as you - combining zones so the radiation demand is large enough to cover the boiler's min turndown so I don't short-cycle.

    Just wire the thermostat terminals on your control(s) in parallel with the one thermostat.

    But the other way, wiring all the circulators to to the 120 side of a single relay, is probably fine too. Circulator pumps of the variety you probably have draw less than 1 amp, and the relay's probably rated at 10 amps or higher.
  • Paul48
    Paul48 Member Posts: 4,469
    I was waiting for Taco, to make sure there is not more than one transformer.
  • JustinS
    JustinS Member Posts: 258
    edited December 2015
    The circulators are 0015 - running on LO, looks like they each draw 0.71 amps and the max load on the SR504-4 is 20A, I think
  • Paul48
    Paul48 Member Posts: 4,469
    Aren't they fused 6 amps? I would think that starting amps could easily be a couple amps each.
  • JustinS
    JustinS Member Posts: 258
    Paul48 said:

    Aren't they fused 6 amps? I would think that starting amps could easily be a couple amps each.

    Maybe I'm not seeing it but there doesn't appear to be any mention of starting amps

    http://www.taco-hvac.com/images/sixplusone/3-SpeedFamily_100-51.pdf
  • MikeG
    MikeG Member Posts: 169
    I have a Taco SR506 swithcing relay. I had a small radiant zone that was too small by itself. I just wired the hot side for that circ to another zone (BB) that runs more often. Both circs are Grundfos 15-58FCs on speed #1. I have not had an issue. Truthfully I don't know if I checked the amp draw or not. Mike
  • Paul48
    Paul48 Member Posts: 4,469
    You might want to contact Taco's tech support. All electric motors spike their amperage when starting. It comes and goes in the blink of an eye, but they all do.
  • JustinS
    JustinS Member Posts: 258
    just called Taco

    Each output relay on the SR504 has a 6 amp fuse

    They advised against what was done for me - said it could compromise the integrity of the controller and cause potential damage

    They recommended that the thermostat inputs be wired in parallel instead... can someone assist on how to do that?

    P.S.

    Gotta love how I just can't trust anyone :-( :-(

    Though, maybe it's OK for just two circulators cause of the 6 amp, three might be pushing it
  • Paul48
    Paul48 Member Posts: 4,469
    Disconnect the t-stats you're not using. Jump terminals left to left to left, and right to right to right. Make sense?
  • JustinS
    JustinS Member Posts: 258
    Paul48 said:

    Disconnect the t-stats you're not using. Jump terminals left to left to left, and right to right to right. Make sense?

    Yeah, I think so... thanks
  • JustinS
    JustinS Member Posts: 258
    Got this taken care of this past weekend

    I left the thermostats that I'm not going to be using right now connected and then just jumpered the W terminals to the one thermostat I am going to use

    Also determined that even with three zones running, my water temperature can't be less than 140F if I want to avoid short-cycling... that's the temp that equals 30K BTU output (min firing rate of boiler)

    Thanks for your help!