New member with a new installation

[Lee F]

Hello all,

Lee here from central NC. I'm a new member with a new installation that I'd like to discuss.

I recently installed a new to me Clayton 1600 furnace. The unit sits in a room which is attached to my carport. The room itself is enclosed but not atmospherically connected to the main house. I have an enclosed fan attached to the main house wall which draws air from the house and sends it through 12" insulated, flexible duct to the furnace then back into the house through a 12" round rigid duct. The unit is vented through 14' of double wall, insulated stainless steel pipe. The chimney is a straight run through the roof and runs from the unit flue opening so there is no un-insulated pipe in the system. This was more expensive however my thinking was that I could keep the exhaust gases hotter on their way up and reduce creosote. I do not have a chimney damper installed. I was worried this unit wouldn't be enough to heat my house, which is ~2400 sq ft. It turns out that I was wrong. This thing cranks out the heat even at very low damper openings. I've been running it for three weeks now and I decided to let it cool off and inspect the firebox and chimney. What I discovered is that it seems to be quickly building up creosote. I am attaching pictures to explain better. I'm burning hardwood which was all cut last year so it "should" be dry. I don't have a moisture meter so I can't be certain. I understand that creosote will build up around the cap because it's exposed to cold air. My questions is; should I be concerned about the buildup in the chimney? I ordered a 6" brush so I'll sweep it this weekend. I don't mind sweeping it as often as needed however I feel like the amount of buildup I have is excessive.

A couple things I know:

I'm burning fires too low because this thing CRANKS out heat. I'm thinking about installing a smaller blower to reduce the air volume around the box meaning the internal firebox temperature will remain higher and reduce buildup. Perhaps I'm wrong here so feel free to chime in.

I do not know the exact moisture content of my firewood so that may be an issue.

I believe this unit was intended to be installed inside a climate controlled area of a home. My unit is sitting in a room which is not controlled so the exterior surfaces of the unit are exposed to cold air. It isn't exposed to wind but certainly to cold air. That may be an issue as well.

The draft is powerful to say the least. I can completely shut both dampers and the fire will continue to burn albeit at a low rate. The damper tubes do leak a little air even when closed so I'm assuming that is where the fire is being fed. The door seals don't seem to leak and there are no signs of air leaking in anywhere else. I have a CO monitor in the hallway where the furnace air is introduced just in case. So far, it's read 0 ppm.

I welcome any comments or information you all may have. Thank you in advance!

-lee

 

[GG Woody]

Moisture meters are cheap, wouldn't hurt to be able to rule out wet wood.
You should be able to add a rheostat to the blower to get a slower fan speed for much less money and hassle than a smaller blower.
I doubt the stove cares that it is in a cold room as long as there is no wind. The stove must make the room warm?
I personally see a bit of a red flag with the insulated flex on your return air if it's the stuff I'm picturing. Your furnace could change air direction if the fan was not active (power out) and melt that stuff.

 

[Lee F]

Moisture meters are cheap, wouldn't hurt to be able to rule out wet wood.
You should be able to add a rheostat to the blower to get a slower fan speed for much less money and hassle than a smaller blower.
I doubt the stove cares that it is in a cold room as long as there is no wind. The stove must make the room warm?
I personally see a bit of a red flag with the insulated flex on your return air if it's the stuff I'm picturing. Your furnace could change air direction if the fan was not active (power out) and melt that stuff.

I completely understand your concern. The flexible duct enters the unit at the bottom of the back side. The air from the unit exits the top at the front. I've noticed that the unit moves air even with the fan off. I'm assuming this is because heat rises and lost air must be replaced? For instance, I started a fire then monitored the incoming air temperature at the supply register. It quickly began to rise even though the fan had not activated. I used a little smoke machine to generate smoke at the return grill. I noticed that it was being pulled into the system. The flex duct was an easy install but honestly, I will probably replace it with rigid duct in the spring.

I just ordered a moisture meter. I didn't know they were so inexpensive. Thanks!

-lee

 

[Lee F]

After reading several dozen posts about older furnaces, such as mine, it seems that I need to get way ahead of the wood supply game. My plan was to split up two or so years worth of wood this winter then maintain a two year supply from there on out. This being my first year running this unit, I guess I got a little too far behind the curve. It's looking like I'll be sweeping this thing every couple of weeks to get through this season.

-lee

 

[hobbyheater]

Hardwood takes 2 /3 years split and under cover to dry!

 

[Lee F]

As an update, I noticed the fan switch was set to its lowest setting, which is A (100°). I changed it to C (120°). Maybe that will raise the vent temperature high enough to cut down on buildup. I guess we'll see. The highest setting is E (140°) so I'll go there next if the results aren't favorable. I know this isn't going to make up for wet wood so I'm still going to get caught up to the pre-storage game. Also, I will post the results of my current wood pile moisture content as soon as the meter arrives.

-lee

 

[brenndatomu]

Those Claytons are just not clean burners...really dry wood and run it hard would be the best way to clean things up some (as much as you can with those)

 

[brenndatomu]

That flex duct is not rated to be used with wood or coal furnaces...if things get too hot it'll melt.
I personally hate forced draft furnaces like that...the ones I've had I ran like a big wood stove, leave the draft blower off and just adjust the damper for a nice controllable burn...but always a dance between too cold/dirty and just plain way too hot!

 

[Lee F]

That flex duct is not rated to be used with wood or coal furnaces...if things get too hot it'll melt.
I personally hate forced draft furnaces like that...the ones I've had I ran like a big wood stove, leave the draft blower off and just adjust the damper for a nice controllable burn...but always a dance between too cold/dirty and just plain way too hot!

My unit doesn't have a draft blower. There are two mechanically adjusted dampers which are basically round caps on a threaded rod that adjust to tighten against a piece of round tube. I'll add a picture to illustrate. The upper damper feeds directly into the firebox. The lower damper feeds into the ash dump, below the grates. I coming around to agree with you. This unit doesn't seem to burn all that efficiently.

-lee

 

[brenndatomu]

My unit doesn't have a draft blower. There are two mechanically adjusted dampers which are basically round caps on a threaded rod that adjust to tighten against a piece of round tube. I'll add a picture to illustrate. The upper damper feeds directly into the firebox. The lower damper feeds into the ash dump, below the grates. I coming around to agree with you. This unit doesn't seem to burn all that efficiently.

-lee

Ah, gotcha...ok so the lower damper is for starting a new fire, and for burning coal...for burning wood close the bottom damper after the fire is established (or very nearly closed) and regulate the fire with the upper one only.
The bottom one can also be used to burn down coals if you ever had a pile that you wanted to reduce some before a reload.