PB 105 venting fire

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Kgdm21

New Member
Jan 7, 2015
2
Massachusetts
I had a fire in my PB 105 exhaust vent on New Years. Happy New Years! I call a couple of chimney installation companies here since and I have been given conflicting information. Before the fire, my exhaust went up 5 ft from the boiler then horizontal about 4 feet which lead to outside. Then there was a "t" and instead of going straight up (because of a window). The pipe went on a 45 degree angle to an end cap faced downwards. I do not have outside air going to the boiler either. One guy said that the piping should be run to the roof of my second story house which would be greater than 30 ft of total piping. The second guy said that the existing setup was fine but that outside air would eliminate my creosote problem. Both guys were amazed at the creosote buildup I had the week after I had cleaned it. I'm not sure what configuration to go with or is another configuration is better. Please help!
 
Hi. I'm totally no expert, but if you're getting all that creosote from a pellet boiler, it'd seem that you're running the boiler too cold or the section with the creosote is cold. Where is all the creosote forming?
 
There are people that own PB105 who'll probably be along soon. But, in the meanwhile, do you currently have any way of assuring that the boiler temperature doesn't get too cool?
 
Thinking that you must have a leak in the system through one or more of the gaskets that seal up the boiler's burn pot. What's the water column in the burn chamber? Have you checked that? Is the air inlet damper opening when the combustion fan is on? Your burn is far too rich in fuel/air ratio, so it sounds like an air problem. I'd check those out. When I clean my vent, all that's in it is fly ash and no creosote. And I have never seen creosote in the boiler anywhere.
 
My boiler has only about 2 feet of pipe outside the external wall before venting into the atmosphere. Otherwise it sounds pretty similar to your layout. Like SmokeEater, anytime I run a brush through the vent I get dry ash and nothing else.

You don't say what your minimum and maximum temperatures are set at. I've got both temperature dials on my boiler turned all the way up. The temp gauge hits about 190 when it shuts down, and the combustion fan starts up within a minute after the circulation pump responds to a call for heat (minimum temp at 180). That way the boiler temp rarely drops much more than a couple degrees below 140.

Lots of burning below 140 can encourage condensation in the fire chamber, which can produce creosote.
 
You definitely have an air leak. I had the same issue with my PB105. What I ended up doing was putting a bead of high temp silicone all the way around where the boiler and ash pan come together and I put 1/2" gasket around the hopper door and the large ash pan door on the opposite side of the existing gasket. Once I did that my creosote problems went away.
 
My chimney setup is similar to yours (except for the 45 degree downslope). chimney works fine. Nothing but dry fly ash whenever I clean it. You are not burning hot enough if you are getting creosote. As said by others, it could be an air leak. Are you getting a good burn from your pellets? I had a batch last year that just didn't burn right---maybe had too much moisture. Switched to another brand after thorough cleaning and all was good.
 
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