Need advice on Lennox GWB8-105S boiler (approximately 7 yrs old) in house I purchased this spring. The unit doesn't seem to be putting out the heat it should. The boiler is rated at 105,000 Btuh (input), 85,000 Btuh (output), 74,000 Btuh (Net I=B=R); 80.4% AFUE. Copper tubing baseboard heat. Single zone. The house is brick construction built in 1961, is 1100 sq. ft., single story with a full unfinished basement (basement is not heated). The first floor sets about 3 feet above ground level, meaning the basement is partially above ground. Basement is concrete blocks with concrete slab floor. Windows are original, single pane with storms. All in good shape (normal wear and tear) with no air leakage noted. Windows in 3 bedrooms are awning windows (north and west side of house) with tight fitting storms, producing a double pane effect. I've covered the internal screens in the bedrooms with insulating plastic and lined the window frames with polyfoam weatherseal to produce a snug, relatively leak free fit for the screens. Windows in kitchen and dining area are typical double hung with aluminum storms. Living room Window is a large picture window with 1/2 width double hung windows on each side, but front of house has an unheated glass enclosed porch so there is no direct exposure to weather on the living room windows. Attic is insulated. House has A/C installed in the attic. House is located in an old city neighborhood in upstate NY with high density lots (30 to 45 feet lot widths), so exposure to wind is minimized by housing and full growth trees. We recently had our first cold snap/snow storm with temperatures in the teens and a wind chill factor of around zero degrees. The internal house temperature would not rise above 67 degrees during this 4 day cold snap. Even with the temperature subsequently rising to the high teens/low twenties, the house would not get warmer than 71 degrees internally. I called the outfit that installed the boiler unit to come and do maintenance on it. They indicated the water in the system was low, the pipes needed to be bled of air, and that most everything else seemed to be in order. The unit is now running at 175 degrees with circa 18 PSI. After the maintenance the house seemed to get about 1 degree warmer in under 20 degree weather. I've been told locally that a general rule of thumb for furnace sizing around this area is 40 Btuh per sq. ft of heated space. Based on that rule of thumb, a 40,000 Btuh unit should suffice to heat this 1100 sq. ft. house? With 74,000 Btuh (Net I=B=R) rating on this unit, I'm having a hard time figuring out why it can't heat this house any warmer than it does. If we get a below zero cold snap, the internal temperature of this house is going to be 60 degrees or colder. Not exactly what I envision for paying the cost of running this boiler full blast. Does anyone have any suggestions as to what the cause of this low performance might be? I'd really appreciate any suggestions - before I freeze to death :>)

Hi everyone, This is my first posting and I hope someone here can help. I have a home that use hot water, baseboard heat. It has an Ack-O-Matic boiler, it looks very old but not sure how old. I couldn't find a model number on it. My problems with the system started last fall. The Armstrong S-25 BF motor was making a lot of noise so I bought a spare to keep handy in case it went out on a cold night. This February I was out of town and my wife called to tell me that the heat on the 2nd floor would not shut off (90 degrees in the bedroom!!). Also the pressure relief valve had blown and dumped water all over. So I had a friend of mine replace the pump until I could get home. When I got home I found that the zone valve to the bedroom was stuck open and would only shut manually. 2 different valve would only open manually. So I had my HVAC guy replace all the zone valve since I figured they were all the same age and would all be going (Erie Controls V8043 replaced with new Honeywells). That was the end of the heating season so I assumed everything was OK. It's a 5 zone system 3 zones on the 1st floor, 1 on the 2nd, 1 on the 3rd. This year when I fired everything up all worked well except that now when a zone valve shuts off there is a loud BANG shortly after the thermostat would kick off and the zone valve would close. The BANG is associated with the valve going off but the BANG comes from further down the line. I placed a towel on the hot valve and held it while my wife turned off the thermostat, I placed one hand on the valve and the other a couple of feet further down the line. It sure felt like the BANG came from further down the line and not at the valve. The pressure tank is an Xtol SX30. There is always a bit of air in the tank (smells REALLY bad). I put a tire pressure gauge on the pressure tank and when heat is not called for my pressure gauge will not move. When hot water is circulating the pressure reads 16 psi on the tire gauge. I cleaned out the water regulator and also replaced the blow off valve. The pressure in the boiler runs from 18 to 22 psi and the temp runs between 140 and 160. I can't get it to go hotter. Is my Aquastat bad? We have bled the air out of the lines until my fingers bled (not literally) and at my HVAC guys advice emptied and refilled the boiler twice. He also says he has double checked the flow valves and they are all OK. My HVAC guy says he has talked to a dozen of his peers and everyone is stumped. It's getting awfully expensive as he keeps coming out to try and figure out what the problem is. I am a super light sleeper and this BANGING is keeping me up all night. I thought that if I could raise the temp to 180 the BANGING might stop but I can't do that unless I drop another $150 plus labor on the new Aquastat. Does anybody here have a thought as to what the problem might be? :wall: Thanks Martin