SmokeEater said:
Just had a "first fire" this past Monday in my new PB 105 and have burned 5 bags of Currans. I have a question for PB owners and other Harman owners on stack temps. Have a bimetallic (I know they're not super accurate) thermometer called a Chimgard on a single wall section of my vent pipe and at full burn I can only see a high temp of about 175 degrees. This seems wicked low to me, but I don't really have any other experience to base my observations on. Anyone out there who can help me out on this?
The PB105 uses a positive pressure vent. You should NOT be using single wall stove pipe anywhere, use only "PL" or "L" rated double wall pipe.
From the manual:
Vent Pipe
4†pellet vent pipe (also known as “PL†vent) is
constructed of two layers with air space between the
layers. This air space acts as an insulator and reduces the
outside surface temperature to allow a minimum clearance
to combustibles as low as 1 inch. In Canada the minimum
clearance to combustibles is 3 inches.
The sections of pipe lock together to form an air tight
seal in most cases; however, in some cases a perfect seal
is not achieved. For this reason and the fact that the boiler
operates with a positive vent pressure, we specify that
all joints within the structure should also be sealed
with silicone.
NOTE:Use only 4†diameter approved PELLET
venting system. Be sure to inspect and clean exhaust
venting system frequently.
But to answer your question, average temp in the stack is between 240 and 350 degrees depending upon whether the boiler is ramping up, or ramping down and the temp of the water coming in from your system.