Everything Drolet Tundra - Heatmax...

[KC Matt]

Why invest in modifications for the furnace, when the attic needs insulated? We have a Caddy, but it's the same firebox. There's no way I could burn thru a full load in two hours, especially hedge or locust. Ideally, you should still be able to heat your home off the coalbed if it remains hot. It was 11 degrees last night and it was 71 in the house after 10 hours. Probably 4 or 5 of those hours were strictly coals and they maintained heat for some time.

I have another project that requires attic access and having mountains of insulation would make that job difficult. After I get to that project insulation is next. Good to hear yours works so well. I obviously need to tweak something with mine.

This stove seems to like Pine as well or better than good hardwoods. It doesn't do too well on hot coals and that's what the hardwoods make. Now good dry Pine will make a rip roaring fire that will heat the house up for sure...you need some insulation to hold the heat for more than 2 hours though.

Damper open after the fire is established is just wasting heat up the chimney...you need to use that manometer and set things up correctly.

A couple loads like that and all you'll have is a full load of hot coals...these things need 8 hours or so to burn a load off...hard to do it in less with hardwoods.

Heatmax is the same furnace with just different trim...you mean the Heatpro?

Absolutely not. That is what SBI claims cracks these things...and a super waste of heat up the chimney.

Have you set your static pressure?
Sounds like you would benefit big time from a temp controller and a blower speed controller (true variable speed, not multi speed like you have now)....my blower runs 98% of the time with little cycling now that I have variable speed...and no, it doesn't blow cold air at the end of the burn.
I'm with ya man, I was so close to throwing mine out in the scrap heap...once multiple issues were sorted out and the temp controller and speed controller were installed it is a whole different machine.

I meant the heatpro but it's good to hear this furnace can do much better than I'm seeing now. Static pressure, no. Where did you buy your variable speed setup and how much did it run? As it is, I don't know this furnace would benefit much from variable speed. It really wants to run on speed 1.

The house doesn't lose a lot of heat in 2 hours, I must have worded that wrong. What is becoming clear is that the Tundra is not good at increasing temps, but will maintain them.

No, not at all.

One thing that comes to mind is for people to not get too hung up on maintaining an exact temp in the house like with fossil fuel heaters. Wood heat fluctuates...some systems more than others.
Also, so what if you have to supplement a bit at 5 AM on a REALLY cold night...we don't really get that many of those kind of nights (days) in a years time, so if your main furnace kicks on for a bit 1 or 2 times per day, big deal...you are still cutting down on you usual heat bill by big margins most likely.
Tundra (and any EPA style wood heater) works best with the intake damper closed once the firebox is up to working temperatures. If your thermostat is calling for heat all the time, holding the damper open non-stop, you are wasting heat and running the bag of your heater for no reason.
I'm a lot happier with the Tundra when I'm just maintaining the temperature in the house than I am coming home to a cold house and using Tundra to try to raise the temp back up more than a couple or 3 degrees or so (at my house YMMV) They just don't have the firepower needed to raise temps a lot unless you are willing to do it over an extended period of time. They work much better maintaining a given acceptable temp range.

Set your heater up per factory specs (all of them)
Use DRY wood.
Have realistic expectations (I have to keep myself in check sometimes too)

Carry on...

I will go through the manual again and see what I missed. The furnaces are sharing ductwork and there is no way to put a backflow damper on the gas furnace. The supply side on the wood furnace would be easy, but then wouldn't it be cycling the warm air straight through the gas furnace? In order to prevent that I've replaced the gas furnace filter with a block off plate and there is another for the Tundra for when the gas furnace is on. Is there a better way to do that without being able to damper the gas furnace?

 

[KC Matt]

Sorry, I should've been more specific.

Is this the controller you are using for your fan setup ?

Scott

The Johnson Control 421 is just a digital controller with single pole double throw relay built in. At the set temp, it opens one circuit and closes another. In this case, the normal position is speed 3, and when it gets cool it switches to speed 1. At this time it appears to be a wasted effort, as the furnace would probably work best left on speed 1 or 2. In order to kick into speed 3 the damper has to be open most of the time.

The second controller that turns the motor on and off is there because the factory switch was not turning the fan on until the supply temp hit between 140 and 156 and turning off while the supply temp was something like 90f. Of the three boxes, the only one that has done any good so far is the one controlling the fan on temp.

 

[STIHLY DAN]

Also, so what if you have to supplement a bit at 5 AM on a REALLY cold night...we don't really get that many of those kind of nights (days) in a years time, so if your main furnace kicks on for a bit 1 or 2 times per day, big deal...you are still cutting down on you usual heat bill by big margins most likely.

but, but, but what if you have no other means of heat? Or its sitting next to it waiting to be installed for 3 years.

 

[STIHLY DAN]

One thing that comes to mind is for people to not get too hung up on maintaining an exact temp in the house like with fossil fuel heaters. Wood heat fluctuates...some systems more than others

This is absolutely true. I would suggest for best results expect up to 6* swing depending on the sweet spot of outdoor temps to your specific application.

 

[brenndatomu]

but, but, but what if you have no other means of heat? Or its sitting next to it waiting to be installed for 3 years.

Well now, that thar is a whole 'nother animal! Better git 'er figured out!
(Or hope for new long johns for Christmas!)

 

[crewchief264]

Is anyone running a whole house humidifier in conjunction with their tundra? If so I'm curious how everyone has their humidifier wired up or any possible concerns with doing this.

I am running an aprilaire 800. No problems.... The main furnace kicks on when humidity is called for... the tundra will continue to operate. I have butterfly dampers on the tundra and a gravity damper above my up flow goodman wood furnace.. as I type this the aprilaire is running. it has been working like this for about 4 years now. No problems.

I have the april air wired up to my goodman furnace just as its called to be wired up from aprilaire in the installation instrutctions. I want the humidifier to run even if I am not burning wood.

 

[brenndatomu]

Where did you buy your variable speed setup and how much did it run?

Ebay, less than $20...but the I'm seeing prices are up on 'em a bit now ($40+)

As it is, I don't know this furnace would benefit much from variable speed. It really wants to run on speed 1.

Mine did too. And it needed to run faster at the beginning. And it cycled a lot at the end. The variable speed setup takes care of all that...

I will go through the manual again and see what I missed.

Setting the static pressure and checking draft are the two main things that are obvious to me.
If the draft is off, that is huge...the "best" furnace in the world is a pile of scrap metal without proper draft (enough, but not too much)
-0.04" WC to -0.06" WC is what SBI calls for. Getting that checked would be the first thing on my list if I were you.

The furnaces are sharing ductwork and there is no way to put a backflow damper on the gas furnace

There's no way? How about a powered damper? Have any pics of your setup?

 

[JRHAWK9]

I am running an aprilaire 800. No problems.... The main furnace kicks on when humidity is called for...

If I had mine setup that way our LP furnace would be running almost all the time during the winter. LOL

I have our April Aire on the wood furnace plenum controlled by a humidistat. It gets power only when the blower on the wood furnace is running and comes on when the humidistat calls for humidity AND the wood furnace blower is running. I don't use it in the dead of winter though as it cools the supply temps off too much and I need as many BTU's as possible. We run a 5 gallon whole house humidifier all day long. We put 5-10 gallons of water in the air a day with that.

 

[zmcnutt]

I am running an aprilaire 800. No problems.... The main furnace kicks on when humidity is called for... the tundra will continue to operate. I have butterfly dampers on the tundra and a gravity damper above my up flow goodman wood furnace.. as I type this the aprilaire is running. it has been working like this for about 4 years now. No problems.

I have the april air wired up to my goodman furnace just as its called to be wired up from aprilaire in the installation instrutctions. I want the humidifier to run even if I am not burning wood.

Good to hear. I was originally concerned about running my lp furnace blower in conjunction with my wood furnace blower however I do have proper dampers to prevent back feeding into each other. I had heard it was best to let the main blower run when humidifying to prevent moisture from rotting the heat exchanger.

 

[crewchief264]

If I had mine setup that way our LP furnace would be running almost all the time during the winter. LOL

I have our April Aire on the wood furnace plenum controlled by a humidistat. It gets power only when the blower on the wood furnace is running and comes on when the humidistat calls for humidity AND the wood furnace blower is running. I don't use it in the dead of winter though as it cools the supply temps off too much and I need as many BTU's as possible. We run a 5 gallon whole house humidifier all day long. We put 5-10 gallons of water in the air a day with that.

EDIT: the April air controller/sensor pack mounts directly on the cold air return plenum.... just fyi....

My April Air has an outdoor temp sensor and it works very well. You may just need to upgrade your Aril Air controller. It actually puts less humidity in the air the colder it gets. I keep it at about 3-4 as for settings. the latest arctic cold snap....... I did need to adjust the humidifier from 4 to 3, as I had some moisture build up on the windows.. I was sitting at about 25% humidity during the cold snap. I am currently sitting at about 35% humidity and the temp is 27 outside with a strong wind. Actually I still get pretty good heat output when the humidifier is running (main furnace on and Tundra on). Although I have not measured duct temps... I like automatic, and KISS. I am loving the Tundra.. It's heating my house with no problems. I am staying above 70 all day and night.. and averaging 8-10 hour burn times. If I don't feel like getting up early and re loading.. I just let the heat pump run for a bit.. I have the main furnace set to kick on at 68. I am also using a lot less wood than the hotblast was eating up.

 

[zmcnutt]

EDIT: the April air controller/sensor pack mounts directly on the cold air return plenum.... just fyi....

My April Air has an outdoor temp sensor and it works very well. You may just need to upgrade your Aril Air controller. It actually puts less humidity in the air the colder it gets. I keep it at about 3-4 as for settings. the latest arctic cold snap....... I did need to adjust the humidifier from 4 to 3, as I had some moisture build up on the windows.. I was sitting at about 25% humidity during the cold snap. I am currently sitting at about 35% humidity and the temp is 27 outside with a strong wind. Actually I still get pretty good heat output when the humidifier is running (main furnace on and Tundra on). Although I have not measured duct temps... I like automatic, and KISS. I am loving the Tundra.. It's heating my house with no problems. I am staying above 70 all day and night.. and averaging 8-10 hour burn times. If I don't feel like getting up early and re loading.. I just let the heat pump run for a bit.. I have the main furnace set to kick on at 68. I am also using a lot less wood than the hotblast was eating up.

I've been pretty happy with the tundra so far definitely takes some getting used to after using my old buck stove. Have you ever measured your static pressure out of the tundra when your furnace is running at the same time? I'm assuming your sharing the ductwork. I guess I need to buy a digital manometer. I just don't want my furnace blower overpowering the tundra so I try to run the two separate from each other as much as possible

 

[JRHAWK9]

EDIT: the April air controller/sensor pack mounts directly on the cold air return plenum.... just fyi....

My April Air has an outdoor temp sensor and it works very well. You may just need to upgrade your Aril Air controller. It actually puts less humidity in the air the colder it gets. I keep it at about 3-4 as for settings. the latest arctic cold snap....... I did need to adjust the humidifier from 4 to 3, as I had some moisture build up on the windows.. I was sitting at about 25% humidity during the cold snap. I am currently sitting at about 35% humidity and the temp is 27 outside with a strong wind. Actually I still get pretty good heat output when the humidifier is running (main furnace on and Tundra on). Although I have not measured duct temps... I like automatic, and KISS. I am loving the Tundra.. It's heating my house with no problems. I am staying above 70 all day and night.. and averaging 8-10 hour burn times. If I don't feel like getting up early and re loading.. I just let the heat pump run for a bit.. I have the main furnace set to kick on at 68. I am also using a lot less wood than the hotblast was eating up.

I have our humidistat upstairs on a wall. We too have the outdoor temp sensor.

What I was getting at was with our low humidity levels, due to the style of house (log cabin with 12/12 pitch roof and TALL ceilings) and seeing it's a not so tightly built house, our humidistat would be calling for humidity a lot in the dead of winter and therefore running the LP a lot with the way it's setup for you. You may have it the "correct" way, but that wouldn't work for us if we don't want to use the LP furnace much. 10 gallons of water a day still nets me low 20's RH when it's really cold out. We also see a bit colder weather than you guys in central IL. This past cold snap we had a 74 HDD (lows of -14° and a high of -3°), while you guys were high 50's the way it looks. I know there's a big difference in heating our place in a 70 HDD vs 55 HDD.

 

[crewchief264]

I've been pretty happy with the tundra so far definitely takes some getting used to after using my old buck stove. Have you ever measured your static pressure out of the tundra when your furnace is running at the same time? I'm assuming your sharing the ductwork. I guess I need to buy a digital manometer. I just don't want my furnace blower overpowering the tundra so I try to run the two separate from each other as much as possible

I haven't gotten into the static pressure measuring. I had originally installed the tundra on blower speed 3. However i didn't get very good overall heat transfer. I backed it down to speed 2. The house furnace over powers the tundra... however the tundra still gets enough air to move air through it and open the butterfly damper allowing some heat through when the humidifier is running. I haven't had any issues with it running like this. And yes the tundra and furnace are on the same return and supply.


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[crewchief264]

I have our humidistat upstairs on a wall. We too have the outdoor temp sensor.

What I was getting at was with our low humidity levels, due to the style of house (log cabin with 12/12 pitch roof and TALL ceilings) and seeing it's a not so tightly built house, our humidistat would be calling for humidity a lot in the dead of winter and therefore running the LP a lot with the way it's setup for you. You may have it the "correct" way, but that wouldn't work for us if we don't want to use the LP furnace much. 10 gallons of water a day still nets me low 20's RH when it's really cold out. We also see a bit colder weather than you guys in central IL. This past cold snap we had a 74 HDD (lows of -14° and a high of -3°), while you guys were high 50's the way it looks. I know there's a big difference in heating our place in a 70 HDD vs 55 HDD.

Copy that. I don't blame you for not wanting that LP kicking in.... I am the same way when mine kicks on the 2 10kw strip heat.... And I am in Decatur IN still not as cold as you and grateful for that. A tundra wouldn't keep up with this same house up there....


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[KC Matt]

Ebay, less than $20...but the I'm seeing prices are up on 'em a bit now ($40+)

Mine did too. And it needed to run faster at the beginning. And it cycled a lot at the end. The variable speed setup takes care of all that...

Setting the static pressure and checking draft are the two main things that are obvious to me.
If the draft is off, that is huge...the "best" furnace in the world is a pile of scrap metal without proper draft (enough, but not too much)
-0.04" WC to -0.06" WC is what SBI calls for. Getting that checked would be the first thing on my list if I were you.

There's no way? How about a powered damper? Have any pics of your setup?

Well, yesterday the replacement damper motor came in. Installing the digital controller on the damper was a huge improvement.

Also, I grabbed the biggest split of honey locust in the garage and tested moisture on a fresh split face. The highest reading I could get was 12.8%.

I looked on ebay using search terms related to your system and didn't find anything. The variable speed blower and motor combos I'm seeing are more like $500+. What terms do I need to search? Is your system 110vac?

You caught me slipping. Theoretically, I could buy a powered damper for $250 or so then have a section of duct remade to add a dog leg, making room for the damper. There's no guarantee it wouldn't require some demo and reconstruction in the finished basement on the other side of the wall. By the time it was done, it would be an easy $600 project and a full day's work, maybe a whole weekend. These things do snowball....

I'll get that manometer installed soon. And static pressure where?

 

[3fordasho]

Totaline P251-0083H head pressure control for the blower speed control.

Well, yesterday the replacement damper motor came in. Installing the digital controller on the damper was a huge improvement.

Also, I grabbed the biggest split of honey locust in the garage and tested moisture on a fresh split face. The highest reading I could get was 12.8%.

I looked on ebay using search terms related to your system and didn't find anything. The variable speed blower and motor combos I'm seeing are more like $500+. What terms do I need to search? Is your system 110vac?

You caught me slipping. Theoretically, I could buy a powered damper for $250 or so then have a section of duct remade to add a dog leg, making room for the damper. There's no guarantee it wouldn't require some demo and reconstruction in the finished basement on the other side of the wall. By the time it was done, it would be an easy $600 project and a full day's work, maybe a whole weekend. These things do snowball....

I'll get that manometer installed soon. And static pressure where?

 

[Digger79]

Just switched from front to back config to side to side. Duct temps seem much lower and flue temps higher I was running fan on high when front to back. I started on high with side to side and have gone down two speeds to medium low incrementally checkin temps by feel each time, still noticing it doesn't seem to be stripping the heat from the unit as well and it's taking allot longer to bring up house temp. I don't understand as according to the manual side by side is their preferred config. Is this because it keeps flue temps higher and doesn't strip as much heat? I didn't add any more elbows or change ducting that much to create restriction. Ugh this is so frustrating as I figured it would be a huge improvement and I just invested a bunch of my time and a little money on it but would have to spend more to change it back:-(. Any advice?

I have been thru this process as well. yes the front location provides much hotter air than the sides or the rear.. However I will say this.. upon max surge of my current Tundra 1 updated unit my duct temps get so high a slight odor begins to arise for a short period of time. I have checked the connections of flex nitareas and no melting of the flex has occurred but I have definitely exceed the recommend temperature for flex. I have solid coming out for the first 20 ft or so then flex running into the crawl space(my tundra is in a stand alone garage), then I have some flex and as much solid as I could put in under the crawl. Point is I like the idea of using the front output but I am pretty sure I would damage my ducts work if my flex connection were any closer than 20ft. I may get away with that now as I initially had flex tied in only 5' from the furnace originally and added more solid duct pushing the flex back to about 20ft. Def need to watch duct temps when using that front connection as it will def exceed safe temperatures and this is likely why SBI says side outputs. Not even sure why the put the front output in the unit. Now that I have my flex connections pushed back 20 ft a may try this but even no w side by side my duct temps get real damn hot upon surge. Things to consider.

 

[Digger79]

Just switched from front to back config to side to side. Duct temps seem much lower and flue temps higher I was running fan on high when front to back. I started on high with side to side and have gone down two speeds to medium low incrementally checkin temps by feel each time, still noticing it doesn't seem to be stripping the heat from the unit as well and it's taking allot longer to bring up house temp. I don't understand as according to the manual side by side is their preferred config. Is this because it keeps flue temps higher and doesn't strip as much heat? I didn't add any more elbows or change ducting that much to create restriction. Ugh this is so frustrating as I figured it would be a huge improvement and I just invested a bunch of my time and a little money on it but would have to spend more to change it back:-(. Any advice?

And don't forget to consider what the older guys on here always mention.. "what can happen if the power goes out and the fan won't run".. that could be a scary scenario.

 

[Digger79]

Forgot to add that above the double wall stove pipe there is 15' of class a terminating 2.5' above the roof. I have a manometer but have not installed it.

Another issue is the amount of coals left at the end of a burn cycle. if the damper is closed or even partialy open (shimmed with a drill bit since my control motor is dead), there are a few inches of coals at the end. At that point you either spend an hour or two burning off the coals, or load what will fit in the firebox, knowing that at the end of that cycle the box will be 1/3 filled with coals. By the time you burn off the coals the house is getting mighty chilly.

Are you guys running your stove with the damper open for the whole burn cycle?

I'll say this.. I have discovered wood heat is wood heat.. or surge heat.. My home is better insulated now and I do believe I am discovering that allowing the Tundra to burn at peak temps, thermostat to call for heat rather than allowing the stove to burn with the damper closed all day results in a warmer house after a 8-10 hour burn. Maintaining an even heat with wood is just not possible without two stoves running in alternate cycles and would consume a huge amount of wood. You see it seems if I let the tundra burn hot as it can without over fire it drives the house up into the middle 70's and drops to about 68 or so by end of burn.. When I run it with damper closed reburning thru most the burn cycle my house winds up around 63-64 after the 8-10 hour burn. So yep it does appear since we are "surge heating" or heating with wood that running tundra with damper open as much as possible does actually provide better heat. This is contrary to everything I believed about this re burning process and what many on here say about Tundra. However the results are def a warmer house period. Yes burns more wood. Keep in mind this is also when using the Tundra as a stand alone heat source. I would think when using as an add on and running in conjunction with a gas furnace the damper closed as much as possible method would be the most efficient. The higher I set my temp controller the warmer the house is at the end of the burn cycles though period.

 

[maple1]

Maintaining an even heat with wood is just not possible without two stoves running in alternate cycles and would consume a huge amount of wood.

It's pretty easy, and the norm, with a boiler & storage.

 

[Digger79]

Maintaining an even heat with wood is just not possible without two stoves running in alternate cycles and would consume a huge amount of wood.

It's pretty easy, and the norm, with a boiler & storage.

Lol ok ya got me there. Cant argue that logic " when heating w forced air only from wood heat" better? Lol. The only storage there is the space being heated an its insulation. However w having a separate gas system using the tundras damper closed method to maintain a longer low level heat an using gas system to make up the difference seems to work well an gives more comfortable even house temps. Going to bed sweating an waking up freezeing at 4 am can kinda suck lol

 

[DoubleB]

Not even sure why the put the front output in the unit.

I think it's the Hotblast, and some other furnaces as well, have the front-and-back outlets, so SBI has the front and back to make the Tundra more salable by being direct bolt-in with existing ductwork.

 

[Digger79]

I think it's the Hotblast, and some other furnaces as well, have the front-and-back outlets, so SBI has the front and back to make the Tundra more salable by being direct bolt-in with existing ductwork.

That sure makes sense

 

[laynes69]

Our Caddy doesn't have a controller on it, and after 8, 10, 12 hours depending on the weather the house is within a degree or two when we wake where the thermostat is set. It was 32 last night, and after a 12 hour burn, the thermostat was set at 73 and the house was 72 with enough coals to still cycle the blower. When it's much colder in the single digits, the thermostat still keeps the house within a degree or two after 8 hours. The days of wild temperature swings dissapeared when we upgraded.

 

[Digger79]

Our Caddy doesn't have a controller on it, and after 8, 10, 12 hours depending on the weather the house is within a degree or two when we wake where the thermostat is set. It was 32 last night, and after a 12 hour burn, the thermostat was set at 73 and the house was 72 with enough coals to still cycle the blower. When it's much colder in the single digits, the thermostat still keeps the house within a degree or two after 8 hours. The days of wild temperature swings dissapeared when we upgraded.

That is probably cause you stove is in the house or basement. My setup is dif my stove is in a stand alone garage pipe in thru my crawl. I get no heat other than what comes from the plenum. No one is getting high heat outta a forced air supply from wood after 8 hrs. Bonus is my garage is heated along w the house but yeah if i had tundra in house im sure i could maintain more even heat using re burn cycle more. In otherwords my heat demand due to set up is far over what Tundra can provide on re burning for 4-5 hrs. When it gets real cold i do better letting it burn at higher heat an a shorter burn. Its my setup. I rent so its best i can do w Tundra for now.