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Wiring Taco SR504-4 Help!

lemoncolly Member Posts: 2
Hi all,

In dire need of some help here, please!

I am currently wiring a Taco SR504-4 to replace an Erie SR601, to support my Buderus Oil Furance and hot water. I cannot seem to get the wiring right for the power in and the wiring to the furnace itself.

This is how my system looks and is wired with the the Erie.

When I go to wire the Taco it is a little different and it has me stumped.
The Taco has spots for the input, so I wire those accordingly. The problem then comes to the wiring that goes to the furnace. There is a black, red and white wire. These would have been to ZC, L1 and L2 respectively on the Erie. In the Taco I tried adding the black to the ZC spot and the red to the hot of the input. But to no avail. No idea where the white goes, as i have tried and the furnace flickers like it is incorrect.

Here is my wiring (as of now) in the Taco:

Any ideas?? I would be forever grateful.



  • STEVEusaPA
    STEVEusaPA Member Posts: 5,977
    I hope you didn’t short anything out.
    What are the red, white and black connected to on the other end.
    HVACNUT Member Posts: 4,868
    The neutral (white wire) connects to L2. The terminal just to the left of L1, where the black and red are connected.
    The black wire on ZC should go to terminal 63 on the 2107 Logamatic.
  • lemoncolly
    lemoncolly Member Posts: 2
    Red goes to 63 on the furnace.
    Black and white to L N.
  • Joe Mattiello
    Joe Mattiello Member Posts: 651
    hi, the SR504-4 is designed to simplify wiring, and not more complicated. the Thermostat wiring is straight forwqrd with red and white to TT terminals at top of control, and corresponding pumps to bottom of control, 120v out.
    The end switch terminal will go to boiler thermostat terminals TT emulating what you have on SR504 control. where it may get complicated is the indirect water heater. The logamatic may have DHW priority built in using the ZC terminal to interrupt power to pumps on DHW demand.
    If you require additional assistance, or have any concerns, contact Taco directly at 401-942-8000, and ask for Tech support.
    let me know how you make out...
    Joe Mattiello
    N. E. Regional Manger, Commercial Products
    Taco Comfort Solutions
    Erin Holohan Haskell
    HVACNUT Member Posts: 4,868
    > @lemoncolly said:
    > Red goes to 63 on the furnace.
    > Black and white to L N.

    From your pic it looks like Red is on L1 and Black is on ZC.
    There needs to be a connection between ZC on the zone board and 63 on the Logamatic.