Help with Unico: Coils cold every winter

KBCL

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

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

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

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

In that case the room should be to hot by now. Figure out why the valve doesn't open when the t'stat calls.