# Hot Blast - Larger Blower Unit



## CCS621 (Nov 25, 2008)

Greetings,
I have a 1300 series Hot Blast wood furnace that I have had for 20 years. We recently had to put an addition on the house and I was thinking about putting a larger blower unit on it to move more air thru the duct-work. Anyone have any experience with this type of modification? Thanks.


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## matt701 (Nov 25, 2008)

I had this blower hooked up on mine for about a year before switching to to a series install with the main furnace. The bigger blower really helped moved the air, even on low speed. I had a switch on it for on/off and low/high. I still have it if interested 
matt


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## CCS621 (Nov 25, 2008)

Thanks Matt, but I already have one that was given to me. I was asking if any one here had used a larger one like yours and if it performed any better than the smaller factory provided blower that came with the furnace. Just looking for input before I modify the heater box. thanks, Rob.


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## Moddoo (Nov 25, 2008)

My furnace also has a large blower unit like the one pictured.
It's a 1/3 hp maybe 12" diameter. Low and high are nice to have also.
It works much better than the stock double toy fans that came with it.


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## CCS621 (Nov 25, 2008)

Thanks, than it should work much better than the single factory blower that my older unit has.


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## matt701 (Nov 25, 2008)

It will definately work better than the original blower that you were using. Mine had 2 original blowers on the back and the bigger one pushed a lot more air, even on low speed. The little ones don't do well with any kind of resistance from the ductwork you hook it to.


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## MNtrees (Nov 25, 2008)

Hi, I would like to see how it hook up with two switches. can you send the info?

Thx,
Patrick


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## bohawg1 (Nov 25, 2008)

*yes*

im interested in this thread myself as i do have the hotblast with the two litttle blowers. I do also have a larger blower like you have and you would swith over to hit if no options for series? Let me know , you get air out of the floor vents but not alot of forced air.


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## matt701 (Nov 25, 2008)

The blower would have to be a 2 speed blower to have the switch on it. If you have more than 2 (3 with a ground) wires going to the blower, you would hook power to the different wires for different fan speeds. If you have a one speed blower, you might be able to install a rheostat, kinda like a dimmer switch to adjust the speed you want the blower to run. I couldnt fit the blower in the back, so I put 2 steel plates over those holes. If you take out the little blowers, you can see in enough to see where there's a good spot to put another hole for the bigger blower. If I remember right, there's about 13 inches of open space all the way around the bottom of the hotlast, so you could put the new blower by the bottom on either side. i used a drill and saber saw, but tin shears works a lot better. Hope this helps.


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## CCS621 (Nov 26, 2008)

Well I installed the larger blower last night and what a difference. Purchased a On-Off-On toggle switch from Home Depot and hooked up the low speed and high speed motor windings. I had to enlarge the blower hole on the furnace from 9-1/2" wide x 5" high to 13-1/4" wide x 8-1/2" high. Even with the furnace on low burn and the fan on high it kept the house at 76 degrees (30 degrees outside). That is the warmest its been since we enlarged the house to 3000 sqft. Keeping in mind that this furnace is only rated to keep a 1300 sqft house warm I am very happy that we didn't't buy a larger furnace. Another plus is the new blower runs quieter than the stock unit.  Wish I did this a couple years ago!


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## matt701 (Nov 26, 2008)

Thats great news! I don't know why the hotblasts don't just come with larger blowers in them. With more airflow, I'll bet you'll burn the same or less wood heating a larger space now. Do you have pics?


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## CCS621 (Nov 26, 2008)

<a href="http://s232.photobucket.com/albums/ee95/ZZRRob/?action=view&current=WoodFurnace002.jpg" target="_blank"><img src="http://i232.photobucket.com/albums/ee95/ZZRRob/WoodFurnace002.jpg" border="0" alt="Photobucket"></a>

<a href="http://s232.photobucket.com/albums/ee95/ZZRRob/?action=view&current=WoodFurnace004.jpg" target="_blank"><img src="http://i232.photobucket.com/albums/ee95/ZZRRob/WoodFurnace004.jpg" border="0" alt="Photobucket"></a>


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## matt701 (Nov 26, 2008)

Good looking install! Are you finding that even on low speed, it will blow more air than the little blowers it came with? Do you have it hooked to the limit switch?


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## MNtrees (Nov 26, 2008)

matt701 said:


> Good looking install! Are you finding that even on low speed, it will blow more air than the little blowers it came with? Do you have it hooked to the limit switch?




Same question with Matt, picture showed the wire plug to outlet, not hook up to fan/limit control box. Do you have to turn it on manually?


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## laynes69 (Nov 26, 2008)

Wire the blower into the limit on the back of the furnace. That way it will only run when you have warm air. You will notice alot better airflow also if you can tie that blower into the cold air return. Looks good. Forgot to add, I added a 3rd 8" duct inbetween the 2 to help with more heat flow. Its amazing how much more heat can be pulled from the units. If I were you, I would close the door damper, and remove the rear plug from the furnace. Let that air help with secondary combustion at the baffle. I then control my heat output with the ashpan damper, not the door. Alot cleaner burn, way more heat.


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## MNtrees (Nov 26, 2008)

laynes69 said:


> Wire the blower into the limit on the back of the furnace. That way it will only run when you have warm air. You will notice alot better airflow also if you can tie that blower into the cold air return. Looks good. Forgot to add, I added a 3rd 8" duct inbetween the 2 to help with more heat flow. Its amazing how much more heat can be pulled from the units. If I were you, I would close the door damper, and remove the rear plug from the furnace. Let that air help with secondary combustion at the baffle. I then control my heat output with the ashpan damper, not the door. Alot cleaner burn, way more heat.




Thanks for the tips!


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## CCS621 (Nov 26, 2008)

Thought about the return air but didn't want to invest in duct work for this 20 year old unit and then possibly not be able to use it on a new large unit. I have an open stairwell with a half door that provides plenty of return air (sort of a central return). I blocked off the door damper long ago because just like the limiter heat switch it became inaccurate after years of cycling on & off. The spring steel looses its temper and stops working as designed. Replaced them before and only got 1-2 years out of new one. As for the use of the limiter switch, once the temp stays below 50 this unit is on all the time, thus no need for it to turn of. In my opinion it is engineered in reverse. I don't want my furnace (in the basement) telling me when it is going to turn on and turn off, that should be decided by a thermostat or myself which is in the living area. If and when I get a new larger unit I plan on installing a control for fan speed in the living area coupled with a thermostat and ducted return air.

laynes69-Great idea about the 3rd vent in between the original 2. I might try that, how do you regulate the air thru the rear plug where you would normally put an air injector? Or is it even neccessary? Thanks, Rob.


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## laynes69 (Nov 26, 2008)

I don't. I do have the rear draft inducer, but I don't use it. Our unit is 20 years old. I rebuilt mine last year. I understand your ideas about how it should work with the blower, but it cannot go into idle and burn cleanly. Thats where gasification boilers have the advantage. I know when the blower starts to kick off its about time for more wood. Think of it as an alarm, that way it doesn't go out. You talk about investing ductwork around a 20 year unit, I did. I reducted my whole home, with supplys and returns around the woodfurnace. I use my LP furnaces blower only, which has 2 leads on the r and g of the circuit board. By me running series, I eliminated the need to have dampers in the system. We have a 2400 sf home, w/10 foot ceilings. Its about 150 years old, but pretty tight. When its 20 out, I can have it 80 in the whole house within minutes. Our never goes out during the winter, 24/7.
The draft inducer makes people think that you can keep a house at a set temp with a furnace. Yeah right, those woodfurnaces need to dump the heat from the unit, or they will overheat quickly. I would think hard about the return. You can always use the ducting for a new furnace, just replacing a few pieces down the road.


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## matt701 (Nov 26, 2008)

If you're happy with it and it's heating your house fine, I can see not investing more money. Let it keep saving you money and save that money until you get a new furnace if you ever need one. I wouldn't have changed mine into series if it worked well the other way. On the topic of savings though, you would save some money only running the blower when the furnace was hot enough instead of all the time, but that could be negated by the more frequent start up draw. Now that mine is heating the whole house nicely, I'm not spending any more on it. I already bought a ton of 8" ducting, an extra blower, limit switches, you name it. I think my wife's happy I'm done messing with ours as I always seem to get blood everywhere working with ductwork haha. Happy Thanksgiving.


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## CowboyAndy (Nov 27, 2008)

Another thing to check is to see if you can adjust the pulley if it is a belt drive. Mine has an expandable pulley (for lack of a better term) that you can open up to make the diameter smaller reducing the speed of the blower.


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## laynes69 (Nov 27, 2008)

I had our blower on our furnace set on high for a coupe years. Still heated well, but decided to turn the blower on low. Now the registers are hotter, and the blower runs longer. Its a slow constant heat, which is still forced through the ductwork.


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## wdchuck (Nov 27, 2008)

This thread answers two questions:
Why the spring steel damper doesn't seem to function as well.
What benefit if any, would a larger blower deliver.

laynes69, good advice as usual. 


I'd recently run some 6" pipe down my chimney, that has helped quite a bit. 

Now I need to find the right blower&motor to push that hotter heat into the house. 
Also a new spring steel control.


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## Stihl Burnin (Dec 13, 2008)

I am preparing to install a larger blower on my Hotblast 1300. The blower that I have purchased is a single speed blower out of a house trailer furnace. I would like to have the ability to control the speed of the fan. Do you think that the dimmer idea would work? What size dimmer would I use? Is a 600 W dimmer large enough to handle the motor on this blower?

I purchased this stove 6 years ago and I really like it, but it just does not push enough air. I was in the process of shopping for a larger stove when I came across this thread. I am excited about upgrading my current stove.


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## mtfallsmikey (Dec 15, 2008)

Hook up a dimmer to a blower...and watch it cook! Need to start a capacitor-type motor on hi spd., then back down...Rheostat-type motor control best, motor/speed controller need to be matched...what is the deal with these furnaces, do they come with only a single speed motor? You can get a 3-4 spd. motor, 120 v. in a 48 frame, or others, best would be a multi-speed 240 v. blower out of a heat pump. Not to be a nitpick CCS, but your supply ducts look to be too small, too much restriction...what size is your supply duct that it ties into? Also build a cabinet around the motor, add a filter grill. Dust inside of blower motor/wheel is bad.


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## Stihl Burnin (Dec 15, 2008)

I got my blower hooked up yesterday. I am still playing with my thermostat settings. I was running with 120 / 80 when I had the small factory blower on it. Those settings worked pretty good for that blower cause all the heat stayed at the stove instead of being pushed into my house. Those settings are worthless with this blower. It is constantly off and on. I have it at at 150 / 80 now. It seems to be working better, but I am still not happy with it. I think it is pushing too much air. It cools the stove very quickly. I am going to look for a multi-speed blower and maybe even a better thermostat control.


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## mtfallsmikey (Dec 16, 2008)

What type of fan/limit control is used in these furnaces?...adjustable?


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## Stihl Burnin (Dec 16, 2008)

It has a round disc on the back of the stove. The disc has an on temp and a shut down temp.


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## mtfallsmikey (Dec 16, 2008)

*Does it look like this?*

http://customer.honeywell.com/honeywell/ProductInfo.aspx/L4064B1469

L4064 series Honeywell fan/limit


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## Stihl Burnin (Dec 16, 2008)

No, it is a disc. I believe it is a honewell though. Probably the cheapest version they offer.


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## mtfallsmikey (Dec 16, 2008)

Small bi-metal limit switch....some are made with adjustable differentials. That's a shame. You could graft the L4064 into your plenum, then you could adjust things some.


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## bohawg1 (Dec 16, 2008)

I have a question i have the us stove 1557 and if i add a reg furnce fan like the guy did in this forum will it cool the stove down to much? Will i have to have really hot fires all the time so it would be in creasote area on the stove pipe temp. Im thinking about doing this myself instead of the two little fans that come witht his but just wondering about cooling the stove down to much, what do you think


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## Stihl Burnin (Dec 16, 2008)

I have had my larger blower hooked up for a few days now. It is pushing too much air through the stove. I am having to burn the stove really hot. It cycles off and on constantly. I need something larger than the factory blower, but smaller than this current blower.

I would also suggest a variable speed fan.


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## laynes69 (Dec 16, 2008)

A larger blower on a thermodisc would cause it to cycle on and off. A larger blower will not cool down the firebox at all. I burn on average 350 to 400 degree temps at the front of the firebox. Producing around 110 to 120 degree air. You need a good clean burn to accomplish it. If you damper all the way down and get the longest burn possible, it won't work. Get a honeywell limit/control for the furnace. It needs a 5 1/2 inch insertion. This way you can get your settings for on and off. If I keep up on the firebox, add a few splits every few hours, the blower will never shut off.


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## Stihl Burnin (Dec 16, 2008)

What size is your blower laynes? Is it variable speed?

What is the benefit of the Honeywell limit / control switch? What do you mean 5 1/2" insertion? It is inserted 5 1/2" into the Outer wall of the stove liner?


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## laynes69 (Dec 17, 2008)

Its at least a 1500 cfm blower. I only use the LP furnaces blower, mines in series. The Lp furnace is a 100,000 btu furnace. The insertion is the length of the contact that enters the jacket around the firebox. Instead of a fixed on/off with the thermodisc, you can set it to where ever you like. If its kicks on too soon, you would up the temp on the control, if it shuts off too soon, you lower the off temp. That way you have a nice constant heat. I can have a 3" coalbed only, and my blowers still come on and run just fine.


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## mtfallsmikey (Dec 17, 2008)

There are several different models of the Honeywell L4064 fan/limit control, with different element lengths, up to 11". These are available at the Box Stores...they come with mounting brackets, or punch the hole for the element and screw it directly to the plenum. Why a lot of these forced-air furnaces have such dinky fans/cheesy controls amazes me!


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## Stihl Burnin (Dec 17, 2008)

My thermo disc has an On temp setting and an Off temp setting. I am not sure I understand how the fan / limit control that you are talking about would be any different. Is it because of the insertion into the jacket instead of being externally mounted?


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## laynes69 (Dec 17, 2008)

http://cgi.ebay.com/Honeywell-L4064...5|66:2|65:12|39:1|240:1318|301:1|293:1|294:50

Here is one.


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## Stihl Burnin (Dec 17, 2008)

I believe that is what I have, mine just looks different because I don't have that cover on it.


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## laynes69 (Dec 17, 2008)

Just work with your settings then till your happy. I'm pushing a hell of alot of air through mine, and I have had nothing but good results. One thing now looking bad stihl burnin, your furnace is smaller than the 1500, 1537g or even the 1400. You may need to place a smaller blower on the unit. That unit is rated for 87,000 btus and hour, mines rated for 119,000 btus an hour. If you could figure in a variable speed switch, you may be okay.


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## mtfallsmikey (Dec 18, 2008)

Cuz the fan on/off, limit settings are adjustable on the L4064


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## Curtis’ (Sep 10, 2019)

Hi my name is Curtis. I just recently bought a hot blast 1331 e and used it last winter. I was researching a larger blower for this unit and found this forum. Not much out there that has any info on it. I can’t seem to look at your pictures you posted and wanted to know if you had the same model. A heating and cooling guy told me it wouldn’t work. My house is 1250 square feet and the single blower just doesn’t warm the house up. If I buy a 3 speed blower and run it on low I feel it would do a much better job.


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## JeffHK454 (Sep 10, 2019)

Curtis’ said:


> Hi my name is Curtis. I just recently bought a hot blast 1331 e and used it last winter. I was researching a larger blower for this unit and found this forum. Not much out there that has any info on it. I can’t seem to look at your pictures you posted and wanted to know if you had the same model. A heating and cooling guy told me it wouldn’t work. My house is 1250 square feet and the single blower just doesn’t warm the house up. If I buy a 3 speed blower and run it on low I feel it would do a much better job.


Not to jump right on you questioning your ability to run a wood burning device but well ...are you sure you ran it properly? I know the Hotblast stuff has a bad rep. for poor efficiency but they make a ton of heat.


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## Curtis’ (Sep 10, 2019)

JeffHK454 said:


> Not to jump right on you questioning your ability to run a wood burning device but well ...are you sure you ran it properly? I know the Hotblast stuff has a bad rep. for poor efficiency but they make a ton of heat.


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## Curtis’ (Sep 10, 2019)

My house has a main electric furnace in the middle of the house. This wood furnace plugs into the existing duct work. The small blower on the wood furnace barely moves the curtains upstairs. I just feel it doesn’t have enough forced air.


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## cantoo (Sep 11, 2019)

Curtis, scroll down in this thread and you will see pictures of the way I set up my old Hotblast using an old furnace fan. Lots of air flow with it. https://www.arboristsite.com/community/threads/hot-blast-1557m-blower.328601/#post-6785412


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## Curtis’ (Sep 12, 2019)

Thanks! That looks like a much bigger furnace than what I have though. Mine has a single small blower on it. Does it matter with the size of the furnace?


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## cantoo (Sep 12, 2019)

Most of the furnace fans are 3 speed so you could just run it on low speed for that smaller stove. You could also likely find a smaller furnace fan from a smaller furnace too. The Hotblast fans don't seem to last too long.


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