High Powered Exhaust

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

earl764

Member
Dec 21, 2011
149
CT
Hello,

Have something of an odd question. First, the issue I'm trying to resolve.

My exhaust pipe is close to the max for my insert.

The specs state: Maximum venting height is 33'

I'm 25-27'. Because of this I can't run the unit at its full power. I can only run it on medium/level 4, and not high/levels 5/6.

I've looked into adding an extra power exhaust fan midway through the venting system(found an inline unit rated for pellet/wood stoves) the wiring becomes kind of messy since you need to run a cord back down inside the chimney. Not very safe or practical in my opinion.

Is anyone aware of an aftermarket exhaust blower upgrade that can be installed to remedy this?

Alternately I would be open to trading/selling the unit and getting one that's rated for the vent length to operate on high.

This crucial bit of information never occurred to me when doing my research/buying. The dealer also never mentioned it being an issue when I gave them my measurements...

The last option would be a freestanding stove, but it's nice to make use of the fireplace as a usable space w/ the insert.

W/ the recent extreme cold, my stove has been cranking but the oil comes on since it's not enough.

My target temperature is 63 degrees, which is warm for us(yes, we're freaks...)

Thanks.
 
earl764 said:
The specs state: Maximum venting height is 33'

I'm 25-27'. Because of this I can't run the unit at its full power. I can only run it on medium/level 4, and not high/levels 5/6.....

Can you explain why you can't run the blower at "full power"??
 
Imacman,

The dealers techs stated that the exhaust blower isn't strong enough to run the unit on high with the height I have.

I've done some extensive testing and whenever I run the unit on 5/6, after a nearly exact amount of time (20ish minutes) the flames suddenly die, you're left w/ smoldering pellets. The auger drops pellets and puts out the small coals.

Unit is religiously cleaned. I even clean the flow tube/nipple w/ pipe cleaners(amazing what gets in there...)

They also mentioned w/ my height, the flow tube gets clogged much quicker/easier than it would if it were a shorter vent.
 
earl764 said:
Imacman,

The dealers techs stated that the exhaust blower isn't strong enough to run the unit on high with the height I have.

I've done some extensive testing and whenever I run the unit on 5/6, after a nearly exact amount of time (20ish minutes) the flames suddenly die, you're left w/ smoldering pellets. The auger drops pellets and puts out the small coals.

Unit is religiously cleaned. I even clean the flow tube/nipple w/ pipe cleaners(amazing what gets in there...)

They also mentioned w/ my height, the flow tube gets clogged much quicker/easier than it would if it were a shorter vent.

Close the damper a bit more if there is one.
 
I've tried the damper option. Going in 1/4 increments down until it was completely closed. It only lengthens the time by a few minutes, sadly.
 
Smokey,

4" pipe all the way to the top w/ the cap mounted per code.

Thanks.
 
earl764 said:
Smokey,

4" pipe all the way to the top w/ the cap mounted per code.

Thanks.

I'd be willing to bet that 3" would cure your high draft situation. You have too much air flow.

Pete or Don where is that OAK bypass is it before or after the damper?

earl764, does the damper actually completely close the air intake or is there a gap between it and any tubing walls, etc ...
 
Smokey,

No. There is a side panel(which can be removed) that the damper hits. It's mainly for looks I think. There is a matching one on the opposite side. The one on the opposite sides open to access the clasps for the door.

The side w/ the damper is normally removed to access various components for maintenance(such as adjust the door).

It's easy to remove. I'll look into adjusting that and seeing what happens.

Thanks.
 
earl764 said:
after a nearly exact amount of time (20ish minutes) the flames suddenly die, you're left w/ smoldering pellets.....

Sounds like a blower thermal trip on the combustion blower. That's the only way I can think of for the fire to "suddenly die". If you shut the stove down at this point, will it re-start with "normal" flames?
 
It will re-start right away.

It's worth noting that in October/November when it was warmer than it is now, we ran the unit on high without any issues.

It seemed that once we hit the first cold snap in December, things went the way they are now.

Thanks.
 
imacman said:
earl764 said:
after a nearly exact amount of time (20ish minutes) the flames suddenly die, you're left w/ smoldering pellets.....

Sounds like a blower thermal trip on the combustion blower. That's the only way I can think of for the fire to "suddenly die". If you shut the stove down at this point, will it re-start with "normal" flames?

Could be but he should be sucking plenty of air through the system, the natural draft alone.

He should also be able to tell if the combustion blower shuts down.
 
I should also note that this is an old house. It's by no means air-tight. I've insulated, etc. but I still have air leaks around some doors. When it's really cold you can feel the air pouring in these small points.
 
SmokeyTheBear said:
Could be but he should be sucking plenty of air through the system, the natural draft alone.

He should also be able to tell if the combustion blower shuts down.

So, you're telling me the combustion blower is still running the same speed, but the flames just suddenly die out? Seems hard to believe.
 
imacman said:
SmokeyTheBear said:
Could be but he should be sucking plenty of air through the system, the natural draft alone.

He should also be able to tell if the combustion blower shuts down.

So, you're telling me the combustion blower is still running the same speed, but the flames just suddenly die out? Seems hard to believe.

Earl didn't say it had stopped running.
 
SmokeyTheBear said:
Earl didn't say it had stopped running.

He also didn't say that it was running either. I was hoping he'd respond to this.

Also like to know what a "flow tube" is.
 
I've spent a lot of time just sitting here watching the fire.

It's in the living room, and we're usually in here with a laptop, etc. so we get to see the whole thing play out.

Works normal, blowers going. All the normal sounds.

The fire then goes down a bit and you have just the coals and some small flames. The flames usually go out fairly soon after this. Some pellets drop, but the fire in the pot is so weak the pellets just scatter/weaken what's left. Sometimes you get lucky and a fire comes back to life w/ a strategically placed ember.

Smokey, in regards to your question about the venting, it's actually a straight shot up the chimney.

The exhaust goes into a quick connect box mounted on the unit and goes up. I've also inspected this part of the stove for ash buildup, and found no issues.
 
Imacman,

It's listed in the travis manual.

http://www.avalonfirestyles.com/TravisDocs/100-01191_000.pdf

>>
Check the nipple and flow switch tube. Insert a pipe cleaner through the nipple to dislodge any
flyash. NOTE: The flow switch will shut off the auger if the tube becomes clogged or dislodged.
<<

I did actually have an issue w/ this earlier in the season. The auger would stop dead. You would need to shut the unit off and let it go through the full cool down scenario. Only after that would he auger function. When I cleaned out the tube and the nipple I found some flyash that darkened my pipe-cleaner. I bought white ones so even the small amount of ash is easily seen.
 
If the stove is not currently running would you please test your gaskets. Let us know the results.
 
The door gasket passes the dollar bill test on all four sides.

Or are there others you're referring to?

Thanks.
 
earl764 said:
The door gasket passes the dollar bill test on all four sides.

Or are there others you're referring to?

Thanks.

Any that would possibly lead to a vacuum loss of any duration that could affect the delivery of pellets to the burn pot.
 
I'll catch up with you tomorrow, it is time to go upstairs and get warm. It is chilly down in the dungeon no pellet heat.
 
Status
Not open for further replies.