harman oxygen starved p38 unit- help

[windrunner]

this problem first came to my attention when unspent pellets or not fully burned pellets were found dropping from the burn pot into the ashbin...

corrected the problem by pulling unit out a bit so that airintake was not exclusively from the outside but also drawing air from inside of the house...

did not like the idea of drawing air/oxygen from inside so i pulled unit out totally to get to the feltlike fabric within the exchange box...

since the felt appeared clogged with soot, the air compressor was used to blow the fabric clean...

reassembled and made sure intake hose fit right up into unit...

everything seemed fine until i used aluminum foil tape to ensure seal around pipe was airtight....

this was not the thing to do because i was back to square one - this caused the fire to starve...

took tape off and enough oxygen seemed to be leaking into unit from room as the pellets are fully consumed by flame...

would like to get some input before i contact harman dealerto determine whether felt fiber filter needs replacement or are we needing to measure/calibrate draught...

thanks in advance for your input....

windr

 

[HarryBack]

What fabric is it you speak of? Im not aware of ANY filter fabric that should belong anywhere near the air intake....would interfere with the damper and cause excessive drag on intake air. by all means, call your dealer.

 

[windrunner]

What fabric is it you speak of? Im not aware of ANY filter fabric that should belong anywhere near the air intake....would interfere with the damper and cause excessive drag on intake air.

thanks for your immediate response...

the fabric or material in question appears to be felt like and is found in the intake/exhaust box...

the liner/filter covers the intake opening and has turned black over time...

hope this additional information sheds some light on the situation...

btw, where's the damper you speak of...

windr

 

[windrunner]

further to previous post....

searched and came across p38 manual and looked at instructions for venting....

included in the description was a diagram and it shows the inlet cover part #1-10-08542 to be a separate unit which simply serves as the name implies a cover at the end of the flexpipe part #2-00-08543

in my set up, however, the flexpipe enters a box/chamber which ALSO has the stainless steel exhaust pipe passing through it...

at the moment i am not on site and cannot remember the name or part number of this exchange system...

if helpful, i'll post that information later...

p.s. not contacting local harman dealer immediately because in past he has not been that helpful and only when i presented alternatives/options gathered elsewhere did he move along with me...

windr

 

[GVA]

The damper is right at the stove it's a little flapper that when running should be open.
I would disconnect the fresh air pipe right at the stove and look to make sure it's not stuck.
As far as fabric in the exchange box? In this the wall thimble? Doesn't seem right, and the fabric was plugged with soot? That doesn't seem right either..

 

[HarryBack]

hm...sounds to me like you have an intake thimble......part number is 677077 ( i think, im not at work)....anyways, this intake thimble would be a black funny-shaped box on the wall, with a large opening in the center, which your exhaust pipe goes through, and a smaller opening, surrounded by numbers (look closely), for the flex pipe. On the outside of the house, it would appear as more of a stainless, square plate, with the pipe coming out in the middle, and a little stainless "roof" that covers the intake grating. Now, this thing is insulated, and the insulation is INSIDE of the thimble. This insulation also covers the air intake hole (flex pipe), so if the thimble is used as just an exhaust thimble, cold air wont stream in through the connection where the flex pipe goes. Now, if you use the air intake (flex pipe) for outside air, YOU MUST CUT THE INSULATION AWAY FROM THE FLEX PIPE CONNECTION! Otherwise you will have GREATLY restricted combustion air, a lousy burn, sooty glass, partially burned pellets, and alot of smoke (some or all of the above), depending upon how much air got thru the insulation. Again, that white "filter" isnt a filter at all, its insulation that MUST be removed prior to using the stove.

Dang, if you are using the intake thimble,and had this stove "professionally" installed, Id suggest you call them and enlighten them. I couldnt find any details online about the intake thimble for you, but from your description, it sounds like thats what you are using.

 

[windrunner]

hm...sounds to me like you have an intake thimble......part number is 677077 ( i think, im not at work)....anyways, this intake thimble would be a black funny-shaped box on the wall, with a large opening in the center, which your exhaust pipe goes through, and a smaller opening, surrounded by numbers (look closely), for the flex pipe. On the outside of the house, it would appear as more of a stainless, square plate, with the pipe coming out in the middle, and a little stainless "roof" that covers the intake grating. Now, this thing is insulated, and the insulation is INSIDE of the thimble. This insulation also covers the air intake hole (flex pipe), so if the thimble is used as just an exhaust thimble, cold air wont stream in through the connection where the flex pipe goes. Now, if you use the air intake (flex pipe) for outside air, YOU MUST CUT THE INSULATION AWAY FROM THE FLEX PIPE CONNECTION! Otherwise you will have GREATLY restricted combustion air, a lousy burn, sooty glass, partially burned pellets, and alot of smoke (some or all of the above), depending upon how much air got thru the insulation. Again, that white "filter" isnt a filter at all, its insulation that MUST be removed prior to using the stove.

Dang, if you are using the intake thimble,and had this stove "professionally" installed, Id suggest you call them and enlighten them. I couldnt find any details online about the intake thimble for you, but from your description, it sounds like thats what you are using.

thanks a million harryback, the description cited is exactly what is in place (intake thimble)...

when you state: "YOU MUST CUT THE INSULATION AWAY FROM THE FLEX PIPE CONNECTION" I take it to mean that once the insulation is cut a hole will appear and it should be the same diameter as the flex pipe

in other words, you want to ensure the opening for intake is free of insulation...

am i reading/understanding you correctly...

windr

 

[HarryBack]

yes, wind, you are. Take a knife, exacto, whatever, and cut a disk of insualtion away which blocks the intake of the flex pipe. If you pull the flex pipe off, and look right into the hole on the intake thinmble it connects to, you'll see a white insualtion....stick the knife in and cut it away. Im fairly sure you'll be amazed at how well you stove works after that.

 

[windrunner]

hi,

just to let everyone know, followed posted instructions/suggestions and unit is burning much more efficient since cutting through the insultation...

windr