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Rheem combi boiler and a taco 504 switching relay.

concegual
concegual Member Posts: 5
in Thermostats and Controls
I wired it according to schematic and the furnace will not turn on unless I jumper the isolated end . If I do this it seems to run as expected... is this correct or am I missing something?

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,517
    need more information and some pictures
  • HVACNUT
    HVACNUT Member Posts: 5,829
    Is the Taco panel new?
    If you're jumping XX on the Taco panel and it runs the boiler, then something is wired wrong with the thermostats or there's an internal problem with the zone panel. Any blown fuses on the zones panel?
  • concegual
    concegual Member Posts: 5
    Taco panel is new.... I went as far as to buy a second one thinking the 1st bad. If  run a jumper between xx furnace runs thermostat s work as they should
  • HVACNUT
    HVACNUT Member Posts: 5,829
    edited November 2021
    "Thermostats work as they should" meaning the corresponding circulators run?
    Can you post some pics of the wiring?
  • concegual
    concegual Member Posts: 5
    I'll post pics once I'm there. And yes proper circulators run and turn on and off with the thermostat. Furnace also will shut down when there is no demand for heat

  • concegual
    concegual Member Posts: 5
    I'm not at the unit so pics will have to wait but on my drive home I think I figured my mistake... The relay should be powered independently from the combi boiler or should it be powered from the external pump power out on the combi boiler? My guess is independently and I powered as if I was using the combi boiler's internal switching. Which if I'm correct only gets power when the unit gets a call for heat... So my relay powers up if I jump XX but if I remove it loses power as soon as the rooms reach temp.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,829
    edited November 2021
    Don't overthink zone controls.

    The easiest thing i can tell anyone about a zone control is "Think of all the zone controls as one big mess of wires pipes and circulator motors all ending at the X X terminals" The zone control X X terminals are the R and W of a normal thermostat. So wire up the boiler as if there are no zone controls, with all the outdoor sensors and other components as if it is only one zone. Once that is done and correctly operational, then you can go to the zone control and make the hot water go where you want it by the thermostats that control the pumps to each room/zone.

    This is a modified diagram from the Rheem Manual (if I selected the correct model)

    See how I have placed the thermostat where the zone control XX terminals are to be connected to the boiler control?

    This is the diagram as it appears in the manual (with a few notes added)



    When you seperate the zoning system from the boiler system it becomes very simple. When you try to look at all the wires at the same time you may get overwhelmed. Since you have the boiler operating when you manually jump XX on the pump control, you may have to check all the wiring from the thermostats to the zone control and see if they are correctly connected in order to operate the pump that matches the thermostat in each zone.

    You are correct... The relay should be powered independently from the combi boiler
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    kcoppmrhemi
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,829
    When you power the zone relay from the "external pump" terminals the thermostats are not able to power up the relay because the relay has no power. The Taco SR 504 needs power in order to activate the XX to turn on the boiler.

    Mr. Ed
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • concegual
    concegual Member Posts: 5
    perfect thx for all the info

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