For 25 years my steam boiler and hot water zone (coil) heater worked fine.
I then had a new system installed. Now, every fall, when I turn the heat back on, the hot water zone unit does not work. The plumber says it is clogged and replaces it.
Two people said the unit is running off the bottom of the boiler and that is the problem (but the older unit worked for decades).
Solutions offered seem to be very expensive or without guarantees of durability.
Can anyone suggest a functional solution?
Have you changed the filter? I found that whenever we had an issue with our boiler, it was due to a backed-up line. (Took me forever to figure this out because I'm from California, so I had no previous experience using boilers). LOL. I'd look online. You can find air filters all over the web. Keep a couple handy so you're not stuck out in the cold!