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Help with Unico: Coils cold every winter

KBCL Member Posts: 2
We have a Unico system in our apartment and every year come winter it is the same problem - despite a working hot water heater, the coils in the Unico system remain cold and no heat comes out.  The pipe (inbound?) is hot but the rest of the coils remain cold.  The first year we replaced the pump based on recommendations from the Unico service rep, the second year we replaced the electric box, the third year we changed the pump to a stronger one (again based on contractor suggestion). It’s now the 4 year and the same issue came up again, and I am afraid if we call a contractor they will tell us to get a new pump again.  Is it really a pump issue or could something else be at play here? 

See below pics of our unit and Taco pump


  • unclejohn
    unclejohn Member Posts: 1,833
    There has to be a air bleed somewhere. Is the zone valve open? Should be a lever you can slide left or right.
    EBEBRATT-Ed Member Posts: 14,534
    edited October 2020
    You need a service tech that knows what he is doing. Where are you located? Check "find a contractor" on this site.

    What has happened in the past? Does it ever work properly?
  • KBCL
    KBCL Member Posts: 2
    edited November 2020
    Thanks all - issue fixed by turning the zone valve to open.  It was in closed position.  Strange because we never switched it to closed and it was working last winter.  

    In any case the coils are hot now so heat should be there shortly.  

    Thanks again everyone for the suggestions!  
  • unclejohn
    unclejohn Member Posts: 1,833
    In that case the room should be to hot by now. Figure out why the valve doesn't open when the t'stat calls.