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Cold fire boiler and idwh

AdamS
AdamS Member Posts: 2
in Domestic Hot Water
Ibc hc33-160 and IDHW IBT 40, Taco SR506-6 relay. Here’s my problem.

The installer used a Taco SR 506-6 zone relay. We keep running out of hot water and I discovered why. 
I noticed when I looked at the control board there’s no wires in the aqua stat  low voltage position 9/10 on the boiler which makes it stop heating the house and then it calls for 170 degrees to fire the water for the IDWH. Instead the aqua stat is only connected to the taco relay panel priority zone 6.

The problem is that when I run out of hot water and the hydrostat makes a call it only goes to the taco and not the boiler which causes the circulator pump to turn on and the taco makes the call to the boiler for radiant heat (which is based on the design temp for that day). So the boiler doesn’t know it’s suppose to be running hotter water to replenish the IDWH.

My question is how do I convey to them I need the Hydrostat also sending a signal to the boiler in the 9-10 position on the control module. Or is there a way to wire the Taco 506 to have an out put for house heat and an output for IDWH? 

For some reason my installer wants to wire it like it’s my old 1976 boiler which I replaced and it was running great. I want to use this new boiler for maximum efficiency.



Comments

  • yellowdog
    yellowdog Member Posts: 166
    most mod-cons have the indirect wired direct to the boiler for this reason. do you have the wiring diagram for the boiler? it should show where the tank sensor and circ get wired in for the indirect so it overrides the outdoor reset.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,300
    edited March 2023
    There is a better way to wire up the DHW pump and thermostat.


    This will get you unlimited DHW.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • HVACNUT
    HVACNUT Member Posts: 6,288
    Yes, as @EdTheHeaterMan said, basically the circulator wiring for the indirect needs to go back to the boilers X2 block, not the Zone panel. 
  • AdamS
    AdamS Member Posts: 2
    Fixed, we wired the taco 007 circ pump to the 120V 123 strip next to LNG while the aquastat is connected to x4. If I want the home circus to shut down while repleneshing the idwh I’ll need the SR506 EXP because it has two sets of dry contacts. Thanks for the help guys. 
    EdTheHeaterMan

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