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  1. #1
    Join Date
    Nov 2011
    Posts
    6

    Unico Smart Control Board Wiring to Aquastat - hotwater coil. Installer wired wrong?

    Howdy,

    Spoke to Unico tech support about wiring to boiler. They can't figure out how things are working. Wiring of control board does not look like the wiring in the manual (bulletin 30-039_2010_09).

    I have a Honeywell L8148E aquastat.

    Installer also hooked up a relay from control board to aquastat. Unico is puzzled by this as well.

    Contractor out of picture because of ... like 8 issues prior to this. This is issue #9, and I've discovered this a year after install.

    So, system runs. Thermostat calls for heat, aquastat relays to circulator, and boiler fires. Unico doesn't know how it's working. Unico (and myself) have concluded installer did a lot of Unico installs for cooling and maybe not so many (if any) for heating.

    Has anyone wired the Smart Control Board for a boiler? If so, can you take a look at the picture attached and tell me if there should be two wires to the left, where the jumper is? The doc says that should be wired to an aquastat.

    All the wires, including the wires to aquastat, are at the top of the control board. They have a wire attached to S1/W2 as well. Maybe that's to the aquastat?

    I've had another contractor out looking at the system, and he was unfamiliar with the Smart Control Board and super cautious, so not much help and it cost me $350 for his consultation.

    Thanks.
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  2. #2
    Join Date
    Jul 2000
    Location
    Northern Wisconsin
    Posts
    2,013
    Ok, I've read your post three times and don't see where you say things aren't working. It reads as if you are getting heat from the unit as expected, but don't agree with or understand how it's being done and Unico technical (from long distance and maybe a few pictures) couldn't answer your concerns.

    As this forum does not allow for DIY answers of any kind, I'm thinking it's going to be next to impossible for anyone to help you in getting answers to your concerns.

    I did look at the wiring diagrams from the bulletin you listed and even though you did didn't include a picture of the terminal connections that are actually being used, I can potentially understand what the contractor did to make the unit work from your description.

    Are you having specific issues with how the unit/system performs that led you to investigate how it was wired?
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  3. #3
    Join Date
    Mar 2004
    Location
    SE Michigan
    Posts
    17,963
    Edit
    Behind the ostensible government sits enthroned an invisible government owing no allegiance and acknowledging no responsibility to the people.

    Theodore Roosevelt

  4. #4
    Join Date
    Nov 2011
    Posts
    6
    We noticed the Unico was blowing cold air. The boiler was off, so I was on the phone with Unico and we walked through the manual. While on the phone, I flipped the boiler power switch off, then back on and it fired up. The Unico tech was adamant the control board should have two wires coming off the boiler connections or aquastat connections on the control board. He was also adamant there shouldn't be a relay between the control board and the boiler. How do I know it's working the way it's supposed to? It runs, but ...

  5. #5
    Join Date
    Jul 2000
    Location
    Northern Wisconsin
    Posts
    2,013
    The best thing I can suggest is that you contact Unico and have them find out through their wholesaler(s) in your area who is considered an expert on the type of install you have so they can put you in touch with someone who can come out and put some eyes and experience on the system and figure things out.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

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