Add on wood furnace

[Nelson2]

Ok I'm in a little pickle and my wife is getting frustrated with me because I'm not getting anything done.

I want to install an add-on wood furnace. This will be the third winter in this house. Year one was with NO insulation in the walls, about 2 inches of fiberglass on the ceiling. Furnace couldn't keep the house at 68 through most of the winter. Year two was halfway insulated, fce ran about half as much, heating bills cut in half.

House is a cape cod with about 1750 square feet. Part of it is insulated very well, part of it not but it will be. I did a couple of heat load calculators online and of course I didn't write the results down, however I vaguely remember the calculated heat load was something along the lines of 70,000btu on the coldest of days in Pittsburgh Pa.

I've pretty much decided on either a mini-Caddy or the mid size Caddy. miniCaddy is 75,000btu output, the Caddy is 140,000. My current 30 year old gas furnace is 110,000 btu which I'm highly skeptical of.

I called a couple vendors and told them I was interested in the mini-Caddy, and after a half hour conversation with the one, he was recommending the mid-sized Caddy for the following reasons: mini Caddy firebox is fairly small and would recommend 16" wood max. He didn't like the loading door on the mini-Caddy. There was one other reason I don't remember. (edit - I do remember now - the mini-Caddy is much more sensitive to moisture content of wood. He said mini-caddy runs like mud unless wood is below 20%. I don't have a moisture meter yet but do think my wood is pretty dry). He said with the bigger unit you can always build a small hot fire with the option of a large hot fire if you want.

So the questions I have:
mini or regular Caddy?: I'm still thinking mini but that conversation threw some doubt in there.
Blower - yes or no? I'm thinking yes, then I essentially have a standalone unit and routing the hot and return ducts would be simpler.
Barometric damper? eh-an option I can add later if needed.

If you've made it this far, thanks for reading! I do appreciate the replies.

Thanks,

Steve

 

[pook]

Ok I'm in a little pickle and my wife is getting frustrated with me because I'm not getting anything done.

I want to install an add-on wood furnace. This will be the third winter in this house. Year one was with NO insulation in the walls, about 2 inches of fiberglass on the ceiling. Furnace couldn't keep the house at 68 through most of the winter. Year two was halfway insulated, fce ran about half as much, heating bills cut in half.

House is a cape cod with about 1750 square feet. Part of it is insulated very well, part of it not but it will be. I did a couple of heat load calculators online and of course I didn't write the results down, however I vaguely remember the calculated heat load was something along the lines of 70,000btu on the coldest of days in Pittsburgh Pa.

I've pretty much decided on either a mini-Caddy or the mid size Caddy. miniCaddy is 75,000btu output, the Caddy is 140,000. My current 30 year old gas furnace is 110,000 btu which I'm highly skeptical of.

I called a couple vendors and told them I was interested in the mini-Caddy, and after a half hour conversation with the one, he was recommending the mid-sized Caddy for the following reasons: mini Caddy firebox is fairly small and would recommend 16" wood max. He didn't like the loading door on the mini-Caddy. There was one other reason I don't remember. (edit - I do remember now - the mini-Caddy is much more sensitive to moisture content of wood. He said mini-caddy runs like mud unless wood is below 20%. I don't have a moisture meter yet but do think my wood is pretty dry). He said with the bigger unit you can always build a small hot fire with the option of a large hot fire if you want.

So the questions I have:
mini or regular Caddy?: I'm still thinking mini but that conversation threw some doubt in there.
Blower - yes or no? I'm thinking yes, then I essentially have a standalone unit and routing the hot and return ducts would be simpler.
Barometric damper? eh-an option I can add later if needed.

If you've made it this far, thanks for reading! I do appreciate the replies.

Thanks,

Steve

large firebox with small fire is not as efficient
get the blower
baro regulates the draft so the stove wont overfire & possibly warp?
learn how to burn= avoid placing new load atop bed of coals if possible rake coals to front. ideal woodfire burns from the top down, front to back as necessary on reload

 

[mustangwagz]

Ok I'm in a little pickle and my wife is getting frustrated with me because I'm not getting anything done.

I want to install an add-on wood furnace. This will be the third winter in this house. Year one was with NO insulation in the walls, about 2 inches of fiberglass on the ceiling. Furnace couldn't keep the house at 68 through most of the winter. Year two was halfway insulated, fce ran about half as much, heating bills cut in half.

House is a cape cod with about 1750 square feet. Part of it is insulated very well, part of it not but it will be. I did a couple of heat load calculators online and of course I didn't write the results down, however I vaguely remember the calculated heat load was something along the lines of 70,000btu on the coldest of days in Pittsburgh Pa.

I've pretty much decided on either a mini-Caddy or the mid size Caddy. miniCaddy is 75,000btu output, the Caddy is 140,000. My current 30 year old gas furnace is 110,000 btu which I'm highly skeptical of.

I called a couple vendors and told them I was interested in the mini-Caddy, and after a half hour conversation with the one, he was recommending the mid-sized Caddy for the following reasons: mini Caddy firebox is fairly small and would recommend 16" wood max. He didn't like the loading door on the mini-Caddy. There was one other reason I don't remember. (edit - I do remember now - the mini-Caddy is much more sensitive to moisture content of wood. He said mini-caddy runs like mud unless wood is below 20%. I don't have a moisture meter yet but do think my wood is pretty dry). He said with the bigger unit you can always build a small hot fire with the option of a large hot fire if you want.

So the questions I have:
mini or regular Caddy?: I'm still thinking mini but that conversation threw some doubt in there.
Blower - yes or no? I'm thinking yes, then I essentially have a standalone unit and routing the hot and return ducts would be simpler.
Barometric damper? eh-an option I can add later if needed.

If you've made it this far, thanks for reading! I do appreciate the replies.

Thanks,

Steve

Nelson, I live in Armstrong County, PA. I got the new englander 3000 add on from home depot, If your house is big, drafty, and un insulated like my old school house is..You'll be sweating this year with a stove like mine. I invite you up to give it a look if you'd like. Cheaper than most other add-on stoves.

ONLY downfall to this unit, it doesnt have a spring loaded auto draft, but..this is no big deal once you figure out your settings. i get 10-12 hours with BIG seasoned wood. Box will take a 25 inch log (thats frickin huge..) and firebox is about 14 wide, and 18 high to the smoke shelf. Buy yourself a Chimney thermometer, and run it about 18" above top of stove. Keep it in the safe burn area, and enjoy the warmth this hog will put out.. Its 90 in here as i speak... i woke up to only coal and embers in the bottom of it this morning, the temp was still 80. lol

Get at me if you wnna check it out first.

 

[laynes69]

Both units won't run right without good seasoned wood. I have the Caddy, and I'm heating a large well insulated Victorian. I would get the Caddy, it doesn't always produce 104,000 btus. It has a btu input of 140,000 not an output. You can build a medium and even small fire and still maintain a clean burn. Being they are EPA certified they do burn clean. If your chimney isn't awfully tall, you won't need a barometric damper. The units require a strong draft due to their design. Get the blower model, you will have more than needed to push the heat from the furnace. We love our furnace. I think on average with the unit closed down it will put out 60,000 btus. I have yet to fill our firebox at night, and still I wake up in the morning with a decent coal bed to load and go.

 

[Nelson2]

Thanks all for the input. Laynes, I've followed your posts all over the internet about the Caddy/USStoves. To say you're a fan is an understatement!

Chimney is your standard 3 flue masonry all the way to the top. 12' of it is fully insulated (living space on all sides), another 10' is roofed in (insulated on inside of house - I could insulate the rest of this as well if needed), and the last 5' exposed. I'm still looking for a way to measure chimney draft accurate down to 0.01's.

Laynes, you're right about the total btu output. I guess the mid-sized is the way to go. It matches the btu output of my highly optimistic output gas furnace and takes longer logs. Also gives the wife the option of upsizing the house like she plans (yeah right).

Although the mini-Caddy is still new, has anyone come across some feedback on their experience with them?

 

[laynes69]

You want a 6" flue for the furnace for it to operate efficiently. I have a 5.5" buts its rigid stainless and 32' tall. Here is a link for a manometer to measure your draft. Its the cheapest I found and its where I bought mine.

http://www.drillspot.com/products/67993/dwyer_mark_ii_25_molded_plastic_u_inclined_manometer#

 

[Nelson2]

The flue size - is that 6" number a minimum or maximum? The terracotta pipe the SS liner would be installed in is 8x8, so I could even get a 7" OD SS pipe. A 7" flue opens up the option for the caddy oil heat option.

 

[laynes69]

7" would be just fine. 6" is a minimum with wood only, but I had to go with a 5.5" due to the existing liner dimensions. Even then it was tight in spots. If have any other questions let me know and I will try to help you.

 

[Nelson2]

Well... I had a bit of a windfall info dump here. PSG updated their website with some new stats I hadn't seen before, and boy am I glad! Essentially, the listed rated btu outputs are under the most ideal of circumstances. There are also PSG lab tests, and then there are the lab tests conducted by the EPA - all of which PSG now lists on their site. For my comparison, they are listed below:

PSG Caddy:
Maximum input capacity 140,000 BTU (41 kW)
Maximum output capacity 106,400 BTU (31,2 kW)
Average output capacity 69,160 BTU (20,3 kW)
Maximum output - EPA test wood 52,000 BTU (15,2 kW)

Mini-Caddy:
Maximum input capacity 75.000 BTU (21,6 kW)
Maximum output capacity 63,750 BTU (18,7 kW)
Average output capacity 41,440 BTU (12,2 kW)
Maximum output - EPA test wood 25,500 BTU (7,5 kW)

Quite a bit different there!!! PSG also changed their description of the mini-caddy to "The Mini-Caddy, as its name suggests, is the miniature version of the Caddy. It is specially designed for the smallest spaces, and is thus ideal for small homes, cottages and small commercial buildings."

This was an exciting discovery. I hope it helps someone else as well!

 

[Nelson2]

7" would be just fine. 6" is a minimum with wood only, but I had to go with a 5.5" due to the existing liner dimensions. Even then it was tight in spots. If have any other questions let me know and I will try to help you.

/aside

Current sportbike motorcycle technology consists of the inlet stacks extending and contracting in response to engine rpm, due to the pressure wave reflected by the motor inlet valves (in proportion to the engine RPM). Now that I think about it, the variable length of the inlet stacks has more to do with engine RPM. Not quite the same ballpark as a steady state furnace draft equation.....

/end aside

/aside
I type too much whilst Staubed
/end aside

 

[biggenius29]

I have a Caddy and love the thing. The thing is very efficient. I have a 34 foot chimney and I did need a Baro damper.


I would recomend the Caddy instead of the mini, it would suck to spend the money just to find out it is to small for you.

 

[Nelson2]

34 feet is flippin huge. 3 stories? Either 3 stories or you have 18 ft ceilings - a tall feet (pun intended).

Can't wait until the Caddy is received and installed. Will report on it later!

(PS - love the obummer stickers.)

 

[Nelson2]

Kaowool for duct insulation making up for combustible clearance

ttt

I work in the steel industry, and typically seal hot metal preheater backboards with Kaowool. I realize no insurance agency would certify or negate the 6" minimum clearance to combustibles of the first 6' of duct work, but this would save me a ton of money in HVAC duct rerouting. Realistically speaking, kaowool easily withstands 2250° F NG fired preheaters

I'm thinking of lining the first 10' or so with this product, in an effort to comply with the above 6" for 6' restriction.

On the other hand, a 1" barrier of Kaowool (noncombustible) may qualify as a non-combustible boundary as it relates to the letter of the law (the instructions, which are written for a typical non-engineered system).

Anyone know anything about what defines a combustible/noncombustible boundary?

Comments please.

 

[pook]

a non-combustible surface in contact with a combustible surface allows for conduction of the heat.Clearance to combustibles may be shortened with a "heat shield" which is a non-combustible board with 1" airspace behind it & allowances for trapped heat escaping from behind it, overhead specs may be different. Also consider the pipe may require clearances so to protect the pipe from overheating as per UL testing.
Time to call codemaster or fire dept. & ask

 

[1harlowr]

Get the mini, you'll be wishing you had the regular size. Get the regular size, you won't be wishing you had the mini.
Why are you half way insulated? Fully insulated will save you more than it costs to insulate. You would use less wood also

 

[Nelson2]

Why are you half way insulated? Fully insulated will save you more than it costs to insulate. You would use less wood also

Haven't got that far yet. Major reno going on, of which insulation is the key driver.

 

[Once-ler]

7" would be just fine. 6" is a minimum with wood only, but I had to go with a 5.5" due to the existing liner dimensions. Even then it was tight in spots. If have any other questions let me know and I will try to help you.

do you have an add on caddy or a just the caddy?
if it is an add on, do you have it in series or parallel?
would you be able post a few pics of your setup?
thanks

 

[laynes69]

I have the Caddy with the direct drive blower. The add-on is just that, and uses the blower of the current central furnace. The add-on is meant to be installed in series only. Our unit is installed in a parallel configuration, which in Canada is illegal.
Our home is very old and the basement is a dungeon, but here it is.
http://www.**********/econtent/index.php?ACT=24&fid=21&aid=24177_FLLWZeWkSznKjdYTQHpz&board_id=1
http://www.**********/econtent/index.php?ACT=24&fid=21&aid=24178_K6QP2dEfY4mFf0AjeRlT&board_id=1

 

[Once-ler]

great, thanks so much for the pics.
do both of your furnaces share one chimney?
if the add on is installed in a series is it true that it needs its own separate chimney?

i almost order the add on today. and then the sales guy said that it needs it own chimney?

to me that doesn't make much sense. my furnace is in the center of my basement and another chimney would block off my hall upstairs?

the house used to have an old oil furnace with an add on that shared the same chimney.

sorry maybe i should have started my own thread

 

[laynes69]

Our furnace is a 90% efficient propane furnace which uses a PVC vent pipe. There are Caddy furnaces that have oil/wood that share 1 flue. How big is your home? How well is it insulated? You cannot share a oil furnace with a wood furnace unless it's a combo and approved.