We bought our Caddy 2 years ago and last winter was the first season. Our chimney was too big and it caused some serious condensation to form from a cool chimney and little draft from lower temperatures. Then this Summer I installed a 5.5" rigid liner. Fixed the low draft, but caused a bad overdraft. Having a 32' chimney I used a barometric damper to keep things in control. About 2 months ago I noticed that the flue temps were less than 100*f at the top of the chimney. The baro was cooling the flue too much and I was worried about condensation and installed a key damper. Well the key damper is not recommended from the maker due to the possibility of low draft speeds and possible backup of combustion products. My burn times were reduced because a key damper still wouldn't bring the speeds down to a managable level, but did help with the temps.
Well a couple of days ago I was reading about the Florida Bungalow Syndrome and decided to investigate. EPA stoves and furnaces were tested with a 15' chimney and not a 32' chimney like ours. I always had decent operation of the furnace, but at times things didn't seem right. I thought why not reduce the inlets on the furnace to make things operate normally. I started by blocking the secondary air ports by 1/2 and seen little difference. When I blocked them at 2/3 the secondaries lit up. There was too much air entering the secondaries which was having the opposite effect. Then I blocked the primary air by about 1/2 to 2/3. Sure the factory inlets are okay, but on a much shorter chimney.
Instantly the fire burned brighter, the flames became lazy and the rate of combustion slowed. I left the aluminum tape there and now for the last 3 days and nights theres no barometric damper or key damper in the flue. The unit can go from full on to full off and have no smoke. The burn times have increased as well as output. Finally after 2 years I no longer have to tinker with a key damper a barometric damper and I don't have the low temperatures in the chimney.
Being the furnace operates from a wall thermostat, its very important that if the damper remains open during a call for heat that things don't overfire. Now that the key damper isn't there or the baro there is no smoke spillage, which was a problem here and there before.
I hope in the future that manufacturers can supply something to control the incoming air based on chimney height. Either that or have different settings for different heights. Those with manual dampers don't have so much of a problem, but with an automatic damper it can make things difficult to fine tune.
https://www.hearth.com/econtent/index.php/wiki/why_stoves_overfire_from_too_much_draft
Well a couple of days ago I was reading about the Florida Bungalow Syndrome and decided to investigate. EPA stoves and furnaces were tested with a 15' chimney and not a 32' chimney like ours. I always had decent operation of the furnace, but at times things didn't seem right. I thought why not reduce the inlets on the furnace to make things operate normally. I started by blocking the secondary air ports by 1/2 and seen little difference. When I blocked them at 2/3 the secondaries lit up. There was too much air entering the secondaries which was having the opposite effect. Then I blocked the primary air by about 1/2 to 2/3. Sure the factory inlets are okay, but on a much shorter chimney.
Instantly the fire burned brighter, the flames became lazy and the rate of combustion slowed. I left the aluminum tape there and now for the last 3 days and nights theres no barometric damper or key damper in the flue. The unit can go from full on to full off and have no smoke. The burn times have increased as well as output. Finally after 2 years I no longer have to tinker with a key damper a barometric damper and I don't have the low temperatures in the chimney.
Being the furnace operates from a wall thermostat, its very important that if the damper remains open during a call for heat that things don't overfire. Now that the key damper isn't there or the baro there is no smoke spillage, which was a problem here and there before.
I hope in the future that manufacturers can supply something to control the incoming air based on chimney height. Either that or have different settings for different heights. Those with manual dampers don't have so much of a problem, but with an automatic damper it can make things difficult to fine tune.
https://www.hearth.com/econtent/index.php/wiki/why_stoves_overfire_from_too_much_draft