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Rheem Combi and Taco Controls

RheemNewbie
RheemNewbie Member Posts: 3
in Thermostats and Controls

Hoping to find some help on wiring this Rheem Combi boiler correctly. I have been reading the manual time and time again and I don't feel confident enough to continue.

Boiler : Rheem RCBH-L199i

Taco Control Module : SR503 - 3 Zone Pump Control

The Taco pump control says to wire as a tankless I need to run wires to the ZC and ZR. Does the Combi boiler have a ZC and ZR? I can't find anything labeled as such.

Or, when using a Rheem Combi, do I wire it as a cold start from the Taco pump control and run the isolated end switches over to the units 13x 3&4?

Thank you in advanced. Very much appreciated.

Comments

  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,500

    Youre are best off calling Rheem Tech support...The Horse's mouth. Mad Dog

    Consulting by Mad Dog & Matt Jr.
  • GGross
    GGross Member Posts: 1,233

    I have never needed to wire a pump control specifically for a mod/con combi. The internal pump and flow sensor on the boiler will handle that. how is this piped? as long as you are hydraulically separated, which you need to be, the internal flow sensor, pump and diverting valve on the combi will handle DHW, no input signal from the control. you just need to wire the zone pumps to turn on and off with the thermostat calls for heat, and hook a dry contact TT from the control to the thermostat terminals on the boiler.

  • Dave H_2
    Dave H_2 Member Posts: 583

    The tankless discussed in the wiring of the SR controller is for a cast iron boiler with a DHW tankless coil installed. It allowed DHW priority.

    The Rheem tankless unit you have is a different animal, priority is achieved internally on the unit. All you need to do with the SR controller is run wires from the XX to the Space Heating terminals on the Rheem unit

    Dave Holdorf

    Technical Training Manager - East

    Taco Comfort Solutions

    GGross
  • RheemNewbie
    RheemNewbie Member Posts: 3

    Thanks so much guys - very much appreciated!! That will be the plan.

    Just so I have a little more understanding of the unit - does the Rheem have the ability to shut the pump off if the water temp is below a certain point, then restart the pump when the water temp catches up? I'm not sure if this is even necessary, or even a thing. I thought I read about it somewhere, that is what was giving me the idea I needed to wire in the zc and zr.

  • GGross
    GGross Member Posts: 1,233

    Your zone pumps will still operate while the combi is in Domestic mode, the Rheem unit does not control the external Taco zone relay you are just running a dry contact from the XX to the boiler to call for heat, it's just a simple open/closed on/off switch. The zones running while DHW is being made won't be a big problem, either way you won't have active space heating while DHW is being produced, this is generally not an issue, nor is it a problem for the pumps to run you just won't get heat from them

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