I've got a strange problem I can't figure out. Last week, the upstairs zone started overheating, even though the stat was set at 62 degrees. I went out and got a new stat. Now I can't get that same upstars zone hot enough. I thought, "oh I guess my Honeywll zone valve must be malfunctioning" and put in a new one. I can't get upstairs hotter than 64 degrees. The other zones work fine and I even changed the boiler temp to 210 and that works fine too. Am I airbvound? If so, how do I get the air out with only an air bleeder in the basement? Can I push water into that zone with a hose? I'm SO confused! Please help.

Hi - i thought this might be electrical question - but didn't see thermostat in any topic My question: Tenant called complaining heat wasn't working properly that thermostat set on 70 inside temp 63 (its below zero right now and a plank house I installed insulation where accessable, but I'd say the insulation is minimal). The furnace would run for a while then stop even though temp wasn't hitting 70. Plumber suggested changing thermostat as it was a programmable one and tenant continually "played" with it. (Tenants girlfriend verified this) Had thermostat changed, system checked (baseboard) everything ok. Called tenant who said "Well it was working ok, but now set on 70 and its only 68 in here". I explained that plumber said thermostat only accurate w/in 3-4 degrees (one of those old dial types) and suggested he put heat where comfortable rather then watching the thermostat. He insisted that at the last place he lived the room temp & setting were always the same. Should room temp read 70 if it set on 70? Or is plumber correct in saying there may be a 3 - 4 degree difference?