how could this happen?

bauer

ok I've got a conundrum here....



2nd floor apartment served by 1 boiler, 1 zone 1 circulator fin baseboard. 



For a long time, we had a severe indoor humidity problem in the apartment --- only during the winter time. We are talking indoor humidities of 80% and above.... creating mold in closets and on window sills.  For awhile we could not figure out where the water was coming from - we tried to isolate variables and got nowhere. I had a good idea that since it only happened in the winter, it had to do with the heating system but couldn't nail it down.



Anyway, few months later, the boiler gets serviced and realize that the fill valve is broken -- allowing pressure to increase.  Since this time, we have closed the fill valve, and the humidity is no longer a problem..... 



Any ideas as to how the broken fill valve could cause this excess humidity? I thought it would just blow a pressure valve or something.  The heater did occasionally shut down and would not fire up for a few hours - looking back maybe it had something to do with the pressure?



Interested in your thoughts on this one...

billtwocase

my only thought

is the expansion tank in the attic? Leaking? Other than that, there is no connection that I can think of. 

STEVEusaPA

I second that

But one other thing..when you closed the fill valve, does the boiler maintain pressure?  Are all the radiators still hot?

Was just wondering if water was leaking out of the system, somewhere in the house, and being constantly replaced by the water feeder

billtwocase

me thinks

he will know soon enough. When the pressure gets low, he will feel the chill. The pressure will probably not get down to zero. Could be a leaky pipe that is steaming behind a knee wall, or something. I would think the ceilings would show something