New Fahrenheit Pellet Furnace installed - some leaks in Type L exhaust venting

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ChrisWNY

Feeling the Heat
After 2-3 years of my wife pestering me to invest in a pellet burner in our newly-built house, I finally buckled and went for a Fahrenheit furnace, which we had installed professionally a couple of days ago (Tuesday, December 28th) by a local dealer in Western NY (near Buffalo). I'm doing the heat ducting myself, so the installers took care of bringing the 380 lb. Fahrenheit unit into my basement, and installed the combustion intake vent as well as the Type L exhaust vent for the furnace. Photos of the installed Fahrenheit unit can be found below.

The only issue after installation was some exhaust leakage into my basement (subtle wood smoke odor inside my home). Upon ignition of the pellets inside the Fahrenheit unit, visible smoke could be seen coming from the Tee at the bottom of the vent (for clean-out), which I promptly sealed with high-temp RTV silicone. I could still smell exhaust after sealing, so I shut the furnace down and re-ignited some hours later, and more smoke could be visibly seen (after initial ignition) coming from the elbow near the top of the Type L exhaust vent, where the exhaust goes outside the house, so I gooped on more high-temp RTV silicone and lathered it by hand all over the elbow joint (the installers sealed the inner vent with red RTV silicone and used aluminum tape at the seams). I'm relatively confident I have sealed the exhaust pipe and that it is air-tight at this point, but was wondering if I need to wait the full 24 hours for the silicone to cure before I can fire up my Fahrenheit unit, the stuff dries to the touch quick but it does have a cure time. The L exhaust vent does not get very hot, I would estimate 120°F maximum, even when the furnace is cranked at the highest setting (Level 5).

Overall, I'm very impressed with the furnace itself, Fahrenheit did a great job of engineering their product and it pumps out a LOT of heat. Also, their support team is very responsive and helpful. It's nice having the unit in my basement as we don't have to worry about any ash or dust/dirt from pellets in our living space.

Here are photos of my install:

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Forgot to mention that the L vent brand is Selkirk Metalbestos, 4" diameter. The vent has about a 5' rise up the poured concrete foundation and then goes out of the house. Outside the house, the vent extends out horizontally about 2' and is capped at the end. The vent (combustion and exhaust) was installed on the Eastern side of my house (prevailing winds come from the West). I just found it odd to see leakage from the T and the 45° elbow considering how well the installers siliconed the inner portion of the pipe, I observed the vent install and they did silicone every piece of pipe (inside). The engineer I spoke with yesterday from Fahrenheit said it's common for those L vents to leak at T's and elbows, and the only thing you can really do is RTV silicone all the seams. I have CO detectors throughout the house so I know this hasn't presented any CO danger. Hopefully my "goop" RTV silicone sealing job did the trick. The venting was installed by pro's who regularly install pellet stoves and furnaces, so once again I was a little disappointed that I was stuck doing DIY high-temp silicone sealing after they were done. You'd think the Type L venting would be more airtight by design considering the potential danger of combustion gasses entering someone's living space. ;)
 
Where is the Tee leaking at? They are normally under a bit of stress so joints tend to open up. If it at the clean out cap a bit of hi temp aluminum tape will seal it up. You'll have to cut it in order to do the cleaning and then replace it. If it is at the saddle, hi temp silicone sealant will fix it right up.

Where is the 45 degree elbow and where is it leaking? Usually a bit of hi temp aluminum tape will help.

However if they used screws and they were too long they may have punctured the inner pipe.
 
The T was leaking out the cap at the bottom, I just siliconed it because I figure it would be even easier to just cut and remove it than aluminum tape. The elbow was leaking at the seams where the tape was used, it was really tough for them to tape that because they had such a limited area to work inside of, it's a narrow area where my foundation comes up near the sill plate, where the house and the foundation meet. I goop'ed on RTV silicone over most of the elbow joint to make sure it was as airtight as possible. There was not enough room for me to actually get a caulking gun into the area, so I would load the silicone onto my hand and spread it on by hand, it was messy but my only option.
 
Very nice unit, Chris. How is the heat generated transferred? Hot water into base boards, forced air? I ask because I don't see any fans or pipes coming out of the unit? Or is there something encased in what looks like flexible venting running underneath your electrical panel? Just curious.....
 
Chain said:
Very nice unit, Chris. How is the heat generated transferred? Hot water into base boards, forced air? I ask because I don't see any fans or pipes coming out of the unit? Or is there something encased in what looks like flexible venting running underneath your electrical panel? Just curious.....

Pretty sure the hot air comes out the big hole at the top, into the ductwork. Same basic setup as my Revolution.

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Chris, nice looking unit, hope you continue to be happy with it, be nice to get another furnace guy on here.
 
You're probably right. I assumed it was completely installed when he took the photos. But your post makes sense and therefore he must not have installed the duct work when he took the photos. That looks like a sweet unit.
 
Chain - the Fahrenheit furnace has yet to be ducted directly into my first floor (in the great room), the large 10" hole at the top is designed for 10" ducting. A good friend of mine does HVAC professionally so both him and myself will be running the heat and return ducts at some point next week, I'll post more photos once the work is complete. For now, only the furnace is installed (along with the exhaust and combustion vents), we've been running pellets through it to cure the paint (get rid of the new furnace smell) and to prime the whole system, more or less. It turns my 1300 sq. ft. basement into an oven in less than an hour. If you take another look at the photos, you can see the 10" return register on the back of the Fahrenheit unit, near the floor. Hossthehermit is right on, there is a 600/800 cfm blower that pumps all the heat out the hole in the top of the furnace.

The Fahrenheit Endurance was really designed to function as a standalone furnace (50,000 BTU max output), though it can be used as a regular stove (sitting on a hearth) or even tied into an existing furnace system. We did not opt to tie the Fahrenheit into our existing furnace/duct work for a couple reasons (A) it was too expensive (lots of dampers needed, just too much of a hassle from an installation/labor standpoint), and the L Vent would have exceeded 20 ft. because of furnace location; (B) it made more sense to pump the heat directly into our first floor where we live 90% of the time, the heat will only passively rise into the 2nd floor. The primary reason for investing in the Fahrenheit this year (beyond the tax credit) was that LP costs are continually rising (we have propane and not natural gas), so offsetting those costs with pellet fuel will save us huge $$$$ over the long run.
 
Chris,

Is the Fahrenheit able to burn grass pellet? I am seeing fuel prices on the rise so that usually means pellets aren't far behind. Just wondering if it is able to burn other fuels besides pellets and corn.
 
j-takeman - Yes, it can burn cherry pits, grass pellets, and most other biomass fuels (http://www.fahrenheittech.com ). Honestly I haven't seen anything other than wood pellets stocked at local stores, not even corn, it still has yet to catch on out my way, then again we're not quite as cold as locations in NE as well as Minnesota, etc.

Premium wood pellets in my area go for ~$4 per 40 lb. bag, or $200-$250 per ton. I have been buying them ad-hoc (10-15 bags at a time) from different locations to see which ones burn best. So far I like the Pennington pellets from Sam's club the best, they seem to burn the cleanest with the least amount of ash. I bought a premium hardwood brand of pellets from my local Tractor Supply store that are supposedly 100% hardwood and they actually burn a little dirtier. I've heard pellet quality can vary significantly even within the same brand, I've read plenty of complaints about Pennington pellets so it's tough to gauge which ones are the best bang for the buck until you actually try them. I have family in the Southern Tier of WNY that get their premium pellet bags $3.50 each (near the Jamestown area), so they are still cheap down there, not really sure why they are so much cheaper just 70 miles from where I live. Either way, if I can heat my house for ~$4 per day on a bag of premium wood pellets, it's MUCH cheaper than a day's worth of heating on LP.

:)
 
Would you have been able to install the unit closer to the wall so you didnt have the horizontal run behind the stove? Ash will tend to settle there so it will have to be cleaned out as well.

Nice looking unit. I think they are built here in my state of Michigan. I have looked at them as well.

Could you take a pic with the front open?

Thanks
BIH
 
Yes, it could have been installed closer to the wall, but in order to gain proper clearance and account for the size of the return housing, I believe it had to be at least 36" from the wall. The installer ordered an L vent pipe that was slightly too long, they offered to come back and replace it with a smaller one (12" smaller), but I told them not to bother since I didn't mind having the extra clearance behind the unit. Either way there would've been a horizontal run there.

Fahrenheit Tech. is located in Holland, Michigan, so you're correct, they are designed and built in your home State.

Here are a couple of shots with the door wide open, taken while burning at Level 4...

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Yep, that's all ash pan down there, owner's manual says it needs to be emptied about once per week if you're running the furnace full blast most of the day. So far I have about 16 hours of run-time on it and the ash pan has nearly no ash in it.
 
Welcome Chris, Nice looking set-up you have there! Enjoy the heat!!!!!
 
Looks good. Keep an eye on the horizontal run for ash build-up. If you tie this into your duct work you will need a back draft damper. If you need one call me, I have one and work you a good price. I also have a hopper extension available.

Eric
330-448-0300
 
Congrats. Looks real nice.. I'd have my recliner in front of the stove !!! Keep us updated.
 
Chris,
That unit looks sweet! How many btu's is it, and how much sqft. do you have on your first floor? You said the basement was about 1300sqft. Also you might be able to get rid of the horizontal run by using 2 45's one directly behind the furnace and one where the pipe goes vertical. I don't know if they make a 45* with a clean out though. I think you did the right thing by not tying into your house furnace, and in the event that you run out of pellets or there is a problem with the pellet furnace you have the main house furnace for back up. I see the future of these pellet furnaces being filled from a pellet truck like the oil or propane trucks. You would have a large 2 ton bin that would be filled by a truck, then from there the pellet furnace would automatically take pellets from the bin. Happy burning.
 
Just wondering why you didn't install a pretty stove on the first floor, most do.
 
doublewide - the unit is 50,000 BTU's (on Level 5 output). My first floor is also about 1300 sq. ft. I like the truck idea, if and when something like that ever becomes available, I'll go for it.

slls - there were a few factors that pushed us toward a furnace in the basement. First and foremost, when we built our house a few years ago, we didn't go for a fireplace (being on LP, we weren't interested in a gas fireplace), I've noticed that most who choose to go for the decorative stove look seal off their fireplaces or discard their wood burners and drop a stove in, we didn't have that option. Secondly, the wife didn't want a stove or furnace taking up space on our first floor, and she didn't want to deal with any ash or soot in the living space. Last but definitely not least, we have an active 18-month old running around and another on the way, so keeping the pellet burner in the basement keeps little hands and fingers off the unit, it's reassuring not to have to worry about the little guy burning himself on a hot stove or furnace.

My next-door neighbor had a gas fireplace when he built his house a year before we did, he got rid of the gas (LP) fire place a couple years ago, dropped in a nice pellet stove and runs the thing 24/7, and completely eliminated using LP for heat. He considered a furnace as well, but went for a stove because he already had a nice fireplace surround and hearth, and didn't want it to become dead weight.
 
slls said:
Just wondering why you didn't install a pretty stove on the first floor, most do.

Aren't you forgeting that stoves are just space heaters?

With this once its ducted He can put the heat where he wants it. The whole house if he wants. Not to mention that this thing is made to go for long periods between cleanings. The hugh ash pan isn'it just for looks. When I can afford it, I'm doing exactly what Chris did! Whole house heat! No cold spots-No fans moving air around. All for just a bit more than the average upper end pellet stove! Priceless.
 
That's another good point - if we wanted to branch some ducts or tie in to existing duct work later on, we'd have that option. Stoves also have their benefits since they provide great localized heat in an area of a house that is used the most. For now, 50,000 BTU's will be more than enough to heat 1300 sq. feet, and I'm betting the heat will rise fairly well up to the 2nd floor also.
 
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