Hot Blast Stove Question 1557M

[Mr Neon]

Hi all! New to this site..Was searching for some options as to maybe figure out my HB stove 1557M.

First time burning wood in the house tonight. Got the furnace installed and working good except for one thing...I am not getting much air in my house through the vents. Both fans are working on the furnace and I checked all the duct dampers for each room in the house. I am getting some air in some rooms but not nearly enough as the gas furnace blower. Plus, I have 2 rooms that I am getting nothing if anything at all. Not good and not impressed.

Now, the duct work was installed into the gas furnace return correctly with one exception.. Instead of using 2-8" duct pipes, we used a "T" and made the 2 duct pipes come together in the "T" and out into one 8" pipe into the return of the gas furnace duct. I am wondering if going 2 into 1 on this wood furnace if that would be restricting air flow in the house.

Cold air return is installed and drawing nice as is everything else. If I run the gas furnace blower along with the 1557M blowers, I get great air movement but after a short period it cools down the air.

So, any suggestions, thoughts? Could I swap the two blowers for a single, larger blower and use a fan limit switch to control it?

Thanks!

 

[zipper1081]

I have a 1537g stove which is about the same stove. Have had it for about 4 years I reall wish I had bought the next model up not real happy with it. But I think the thing you did with the T in to one 8 inch is hurting you alot, I also have my 2 8 inch pipes running right into the main trunk line of the house. I dont understand running them in the cold air return of your furnance. I only use the blowers on the stove and I get plenty of air flow & I have a large 2 story house. Hope this helps.

 

[Junkfxr]

We,ve had a Hot Blast 1500 running for 13 years now with no problems at all but I have BOTH 8" ducts running into the main duct trunk. You're probably losing a lot with choking the two ducts down to one and then running it through the cold air return on the gas furnace. The directions advise against that. It's awfully hard on the A coil for the A/C too if you have one.

 

[Mr Neon]

I think I may have confused some on what I did.

The two 8" returns ducts from the 1557M are not in the cold air return of the main gas furnace. I do have the filter box attached to the cold air return as required by the instructions and that works fine.

What I did was take the two 8" output ducts from the wood burner into a "T" of one 8" and installed that into the main duct run of the furnace. I installed it right above the "A" coil of the furnace plenum. I realized that was not good due to the air movement being restricted so I am currently re-doing the ducts so that I have both 8" returns going into the main duct work of the house as this should and will increase air flow.

Has anyone installed anti-backdraft dampers into the two 8" duct returns of the Hot Blast? Just curious if say your not home to load the wood furnace and the temp of the house goes down that the gas furnace kicks on and the air could possible be diverted a bit back into the two 8" ducts. The only other problem maybe with a damper is if power goes out and you can use the Hot Blast to still heat the house somewhat but if you have dampers, no air to open them up...possible causing and overheat situation in the ductwork?

I guess from reading all the boards on this furnace it is a learning curve with each and everyone who has this model or similar.

 

[sawkiller]

I have a hotblast and they don't put out near the CFM of your normal furnace blower. But when used in conjunction with your furnace fan they work just fine. I have found that I rarely need my furnace blower with my hotblast as the slow steady movement of air heats my home just fine in all but the coldest of times. I do however use the circulate function on my thermostat which occasionaly kicks on the furnace blower and helps to even out temps in the house but not all thermostats will have that option.

I do have manual dampers in my two trunks that lead to the furnace so I can shut off airflow in the summer and if I need to use the gas funace I can shut them. I don't have a return on my system but I can open a register vent in the garage to suplement the return air make up. I typicaly just open a garage window to allow for makeup air for the system.

 

[Mr Neon]

What about using an air cycler thermostat? I have also heard this is another way to circulate heat more efficiently by timing your main furnace blowing to run at intervals during heating or cooling season.

 

[NCHornet]

I am not a wood furnace expert, but I believe running the two 8" supply vents into a Y and only 8" coming out is not a good thing. I have the 1557 and I have a plennom box on top of my stove but I have a 12" line coming out of the plennum box. I believe the plennum box is better than a Y. The 12" supply line then is plumbed to my existing duct work directly above the A Coil. I am very happy with the way it is heating my home. If I can help in any way just ask.
NCH

 

[Mr Neon]

I have since fixed my duct problem and get goo heat now but the other issue with the hot blast is getting it "tuned" to burn better and longer. I recently installed a barometric draft to help but I am not believing this is working. I have good wood this year, hardwoods, dried, etc.. But lately the burner seems to take forever to get going.

I have a stainless steel liner, less than 20 feet. Good draft or so I believe. I am wondering if I may need a draft inducer. As for burn time..I am lucky to get 6 hours. Love the furnace but getting it dialed in is a PIA!

 

[huntindog1]

I used to burn a Wood Furnace not sure if yours works the same but after having burned a wood furnance for 14 years I have a few tips.

Your wood is burning too quick if you don't have good air flow. Your not getting all the heat from the stove to the house. Its all about the volume of air. Two 8 inch ducts is not enough volume of air. You first have to to have a plenum on top of your Furnance that is well insulated with the foil backed insulation and taped with the aluminum tape for ducts. The size of the Plenum must be as large as you can get it as its the heat storage device for the furnace before the furnace blower kicks on. There should be a thermostat that kicks the blower on and off based on the temperature of the plenum or exterior of the furnace. A trick is to set that on and off so that you get longer run times for the furnance blower as if you can get that run time longer you get a better mixing of the air upstairs in your house plus you get more warm air up in the house which means your extracting more heat in the stove. You also have to think about this that even tho your blower is still blowing and the air doesnt feel hot this isnt a bad thing as air that is barely warm coming out of your vents is still heating your house and mixing into the air up in the house. My plenum was twice the area size of my main duct and the main duct was also running the entire length of my house then 8 inch ducts coming off the main square galvanized ducts to each room. My return was also the same size as my main duct as in a system like this air volume is only as weak as your weakest link so to speak. So back to wood burning too quick you should also have a thermostat that opens a damper to fire the stove hotter when you need heat that then the extra heat heats up the plenum to the point the blowers kick on. Here is another point that you can set the thermostat to close the air inlet damper sooner (after it has been opened , its called hysteresis setting)before the house heats up so as to not have the damper open too long and burn up all your wood too fast. So think of it like giving the stove short blasts of combustion air rather than open it till the house heats up, so you will have to fine tune it.

So if you get more volume of air and have the blowers pushing more air into the house for longer period of time even if its just slightly warm air and you get the short bursts of combustion intake air set to a better setting (which is a setting of the main thermostat called hysteresis) then you will heat your house better and burn less wood. I would say if your plenum only has 2 8 inch ducts that you would need 2 more totaling 4 8 inch ducts going to the main duct. Make sure you have a huge I mean huge plenum on top of the furnace.

One last tip if its one of those super super cold nights and you want to make sure you keep the house warm and get max burn time out of the stove, the tip is on my stove you could switch the blower on to run all the time. I had a 3 speed blower fan that could be set manually so I would set it on low speed and switch it on to run all the time and this will get all the heat out of the stove and mix the air the best up in the house, the thermostat up stairs will still be cycling to tell the stove to heat up but the cycles will be fewer that allows more combustion air into the fire box so the fewer thermostat cycles, the less wood burned and longer burn time. Plus you can use a flue pipe damper for an added extra control if your chimney draws too much but make sure your not getting creosote formation from using too much flue pipe dampening. Good luck!

 

[Mr Neon]

Thanks for the tips!

Here is what is happening. First I get pretty good heat flow when the furnace fans kick on. They are controlled by a thermodisc as opposed to a fan limit switch, so I cannot adjust the controls unless I switch it out. The blowers are 2-500 cfm fans, not the greatest but I am looking to remove then someday and use a furnace blower instead..just don;t know what type at this time.

As for burn times..It takes a while to get the fire going and once it get going it will burn decent if I open the spin dial on the ash door and the main door setting as well. Seems it is not getting enough air but then after it gets enough hot coals, I will dial it way down and then it will almost kill the fire.

I usually load up at night with hardwoods, dial the damper down closed then open it about 1 turn. The feed door damper is closed and the flue damper is about 3/4 closed. Seems like it will work, but best I got was about 6 hours with about 5 good logs. In the morning it is all ash or some pieces left. The barometric damper does not seem to help as much as I thought but then I am still setting it properly. It sticks as if the round adjustment lid is a little too big. I may have to grind it down a hair to give it more movement freely.

All in all, it does heat the house good. just need to get times burn times better at night!

 

[CrappieKeith]

I usually load up at night with hardwoods, dial the damper down closed then open it about 1 turn. The feed door damper is closed and the flue damper is about 3/4 closed. Seems like it will work, but best I got was about 6 hours with about 5 good logs. In the morning it is all ash or some pieces left. The barometric damper does not seem to help as much as I thought but then I am still setting it properly. It sticks as if the round adjustment lid is a little too big. I may have to grind it down a hair to give it more movement freely.

All in all, it does heat the house good. just need to get times burn times better at night!

I've been following your dilemma...although you may think burning wood is a no brainer you are wrong.
Well it'snot the burning it's thinking that you do not need professional help.
How many CFM's does your home require? What is the static pressure in your ducting? These are a few things you may want to know while you are trying to figure out blower sizing or moving air through your ducting.
Hire a pro for a few hours...it could be worth a lot in the end.

You said that you added a barometric draft regulator...do you have a manometer to set the draft speed to the desired setting...I believe your manual calls for.04" of water column to a max of.06"
Here again a pro could help. You could also buy your own manometer and do your own testing.Without the ability to do any exacting measurements your burning blind.

You might get it all dialed in to find it just does not do what you want it to do.
Adding insulation can be a help to your home....or then again getting the correct furnace may be the other choice.

 

[Mr Neon]

House has new windows and is semi-insulated. The burner last year got the house too hot at times but for the most it did good.

I figured this is my second year with the burner and each time, I will more than likely do "improvements" to at least get better results. I have not put a manometer on the barometric damper yet, that I need to do. What I did different this year was re-plump the 6" flue pipe to the liner a bit different. I ran it an incline but a bit longer than when first installed. My liner and chimney sits about 6 feet from the burner so I had to use a series of 45 degree duct pipe to work around the proposed wall in my basement. I do not think that would have any effect of how it preforms but I could be wrong. There re no sharp bends except the final 45 into the liner.

One other issue I just though of is the liner itself. Last year, I had to clean out my chimney mid-season due to creosote build up that clogged the bottom of the flue where the burner black pipe connected to the liner. Not fun but after it was cleaned, what a difference. The liner was mostly clean and free of the creosote becasue it didn't stick but just dried and dropped to the bottom. My liner has a "T" fitting with a lid on the bottom of the "T", if I remove this lid, the creosote will fall to the inside of the foundation and I will not get any build-up of creosote and or clogs. Problem is I do not have a trap or clean-out door in the cinder block wall where the liner is. I can bust a brick or two out and installed a clean-out door but again there is another problem. The manufacture of the liner strongly advise me not to remove the lid from the bottom of the "T" as it will void the UL label of the liner and if the burner threw a spark through the flue pipe it could cause the creosote laying on the bottom to ignite, thus I got a chimney fire that is not contained in the liner. The whole idea of this liner is that is will contained any fire so as to not be inside the chimney reducing and real risk to the house. My thought is that I have at least 5 feet plus of flue pipe from the burner to where it connects to the liner. The opening from the chimney to the bottom of the foundation is about 4 feet. If I clean each season, would that still create a fire risk in the chimney with the liner? All I want it for the creosote to fall on the bottom instead of me tearing down the flue pipe mid season again before it clogs up..plus it will be a lot easier to clean everything than tearing it done twice a year. Seems this is an issue that may or may not be corrected depending on who you talk to.

 

[NCHornet]

That was the one mistake I made when I plumbed by chimney pipe. Mine comes out of the stove right into a 90 and then about 6 ft of chimney pipe before it enters my flue liner in the existing chimney. This is not going to help when I need to clean the pipe of any creosote. Instead of the 90 I should have used a T, with one side capped. I then could remove the cap and have a straight shot up to the chimney. I did a lot of reading and I asked a lot of questions before I installed my 1557M. Thinking that the 1557 will push the same amount of air as your existing system isn't likely to happen. Even if it isn't pushing as much as the existing unit it is still pushing hot air into the home. As said above, the plennum on top of my wood furnace is almost as large as the entire top of the stove. It sits in about 1 1/2" all the way around. I believe the 12" line coming out of this plennum box is a good size, at least it is working fine for me and my needs. Last night I went to bed early, around 9:00 and I filled the wood box with about 6 pieces of hardwood. I placed them as close as I could so there were only small gaps between each piece. I woke up this morning and at 7:00 AM the house was at 74, and when I opened the door on the fire box I couldn't hardly stand in front of it. My stack temps were at 300 degrees. There were some small pieces that were still burning, but I had a good 4 inches of red hot coals at the base of the fire box. I was very happy with this. I had the dampner on the chimney pipe was about 70% closed, the fire box door vent of closed and the ash door vent was only open 1 full turn. I am amazed how much the slightest adjustment can affect how the fire burns and for how long it burns. Everything I have read about the Baro said it was a waste of money. When my blowers due fail I will probably replace the two with one quality blower, no way am I paying what US Stove wants for them.

 

[smokinj]

Might start by taking a good look at your wood supply.

 

[Mr Neon]

Wood supply this year is very good...Last year was not so good, so I made sure of that!!

So what is really the thought on the barometric dampers? Are they good or a waste of money?

 

[smokinj]

Wood supply this year is very good...Last year was not so good, so I made sure of that!!

So what is really the thought on the barometric dampers? Are they good or a waste of money?

Waste of money. There ok in a very windy day with less than good wood. Otherwise just not worth it. I am running the same set-up as you other than I am running a full 8 inch for both sides. Mine runs very well on seasoned hardwoods. Hickory locust ash. I been running mine for 6 years now and every proplem I have ran into came down to the wood its self. Be hard to correct wood supply in just one year.

 

[Mr Neon]

Well..what I used last year was from my neighbors yard. We took down 6 trees, mostly cherry and had some wood prior before getting out wood burners. Wood sat outside covered/uncovered for about 2 years. I also got wood form local guy and mill cut-off blocks. So, I learned or I am learning to actually go to the place that has the wood and see it for myself as opposed to just taking their word for it.

I figure I will be learning through the seasons but I do enjoy the heat it puts out.

The other question was my liner with the "T" in it. Was hoping to get some feedback on that as to the lid on the bottom to leave on or take off to keep the creosote from accumulating in the liner thus blocking off the draft. I hate cleaning it twice a year.

 

[smokinj]

Well..what I used last year was from my neighbors yard. We took down 6 trees, mostly cherry and had some wood prior before getting out wood burners. Wood sat outside covered/uncovered for about 2 years. I also got wood form local guy and mill cut-off blocks. So, I learned or I am learning to actually go to the place that has the wood and see it for myself as opposed to just taking their word for it.

I figure I will be learning through the seasons but I do enjoy the heat it puts out.

The other question was my liner with the "T" in it. Was hoping to get some feedback on that as to the lid on the bottom to leave on or take off to keep the creosote from accumulating in the liner thus blocking off the draft. I hate cleaning it twice a year.

Mine does not work well unless its block off. In 6 years I have not needed to clean my flu. Its double s/s insulated.

 

[Mr Neon]

Well, one guess it that I am sure it is the wood from last year that caused a lot of build-up in my liner. I also got a double lined stainless steel. company called Chimney Depot makes them.

I also used a creosote remover that you put on the logs while burning..got it at Tractor Supply...Works great but found I should not use it with the liner..

Always learning.

 

[smokinj]

Well, one guess it that I am sure it is the wood from last year that caused a lot of build-up in my liner. I also got a double lined stainless steel. company called Chimney Depot makes them.

I also used a creosote remover that you put on the logs while burning..got it at Tractor Supply...Works great but found I should not use it with the liner..

Always learning.

Well if your getting build up seems your fire is not real hot. Open it up 2 times a day to get it hot. We have the same flu's as-well and mine stays clean. Now my wood supply is top notch 18 months on hickory ash sugar locust. My oak I will give another year. So far this year I am on my second cord of locust. Cherry silver maple things like that work but no-way near the good seasoned hardwoods. The milling blocks are great for mixing with simi-seasoned wood and when its bitter cold 100 percent makes a kick @ss fire.