Unless you want the ability to run both furnaces at the same time in extreme weather when ones home has a very high heat load.
2 separate returns will still allow this.
Everything Drolet Tundra - Heatmax...
- Thread starter brenndatomu
- Start date
-
Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.
We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.
We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
2 separate returns will still allow this.
JRHAWK9
Minister of Fire
This is true, but for the average homeowner, running two completely separate returns would be a big pain.
Ours share a single return and they operate just fine together if need be. For us though the woodfurnace carries the house 99% of the time. I think the year before last I ran the LP 3 or 4 cycles, with a single cycle a day. Our system is setup that when either operate, the flow is cut in the opposite direction, but if they both operate the butterfly damper over the woodfurnace opens for the woodfurnace and for the central furnace. The previews setup contained zero dampers which was setup in series. With that setup because the woodfurnace would go out overnight, both would operate all the time.
JRHAWK9
Minister of Fire
Unfortunately for you, you are by far not an average homeowner.M.r jrhawk9, self made "wood heating engineer guru."
lol, maybe in a Red Green way. I'm not even close to some of you more knowledgeable guys on this site.
JRHAWK9
Minister of Fire
same here. Last winter, not counting the days we were gone, according to my spreadsheet the wood furnace handled 99.4% of the total BTU's. I did the same thing, I let it cycle once a day if needed....it was always in the morning at the end of a burn (after a re-load) for an hour or so with both blowers running at the same time. Otherwise including the time we were gone it handled 96% of the total BTU's.
Having them both share the same return, won't they "fight" over the return air and one possibly scavenge from the other? That would be my concern.
There's a possibility, but either unit has never overheated or stalled when operating. Our woodfurnace has two plenums like a central furnace. The dampers are preweighted, so there's no electronics involved. I'm with the KISS method.
JRHAWK9
Minister of Fire
Nothing wrong with that as long as it works.
There's a possibility either tomorrow morning and/or Monday morning I'll be running both for a bit. Supposed to be -12° tonight with a high of -3° tomorrow and -15° Sunday night with -30°+ wind chills. We are normally a few degrees colder than the forecast due to being in a more rural area though, so we -may- be pushing -20° come Monday morning. Wish those damn Canadians would just keep their arctic air on their side of the border.
There's a possibility either tomorrow morning and/or Monday morning I'll be running both for a bit. Supposed to be -12° tonight with a high of -3° tomorrow and -15° Sunday night with -30°+ wind chills. We are normally a few degrees colder than the forecast due to being in a more rural area though, so we -may- be pushing -20° come Monday morning. Wish those damn Canadians would just keep their arctic air on their side of the border.
I suppose you could turn one fan off and check the pressure at the ducts to see if its slowing one or the other. I bet the difference is minor or none. So long enough air can get through I'd think air speed would simply increase in the return line to the split out to each fan. Should pull a little harder to suck the extra required air through the same size pipe. I dunno lol.
Messed with the fan switch a little bit on the Updated Tundra model 1. Used a few layers of high temp foil tape underneath and removed rear screw. This caused the switch to fire a little later letting firebox get hotter during end of burns. We'll see how this works for now. Seems it is a minor adjustment so far.
Last edited:
jb6l6gc
Minister of Fire
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?
Last edited:
DoubleB
Minister of Fire
I don't know the answer, but a few thoughts:
-I'd run a few more loads or days, just to see if you have consistently lower temps. Sometimes I didn't pack as much wood in as I thought, or it's not as dry as the previous day's load, or there's more small stuff in there that gives quicker hotter heat, or the species is different, or the return air temp is colder than usual (it's really cold here today), etc. There's no harm in giving it a few days to confirm if it's worse.
-I originally had front and back config because the installers didn't do it the way I asked them. I ran it that way a few months before I changed it to side-to-side. I didn't notice a performance difference (but maybe I wasn't observant enough).
-The manual says to use side-to-side for "optimum efficiency", which we would think means maximum heat (efficiency), but I suppose you're right, that optimum might be less heat if it improves something else more. Given SBI's non-satisfying technical answers to other questions, your guess is probably as good as theirs.
-I feel your pain. I've done some mods that were busts, I'm in season #3 and still fiddling with things that sometimes feel (and are) wasted. But nothing risked = nothing gained.
I'll throw a couple thought in too.
I'd also say to live with it a little while to get a feel of the real world results (house warmer or cooler)
Also, I don't like "guessing" on temps, I'd get some real thermometer reading so you have better data to work with there. "Feel" can lie sometimes.
Back when these things came out and there was a thread over on the other site by a SBI employee, the duct placement was discussed and I believe he said the airflow through the unit was best side/side and it pulls heat off all 3 HE tubes better instead of more so the center tube...but I dunno...these things defy "logic" sometimes...
I'd also say to live with it a little while to get a feel of the real world results (house warmer or cooler)
Also, I don't like "guessing" on temps, I'd get some real thermometer reading so you have better data to work with there. "Feel" can lie sometimes.
Back when these things came out and there was a thread over on the other site by a SBI employee, the duct placement was discussed and I believe he said the airflow through the unit was best side/side and it pulls heat off all 3 HE tubes better instead of more so the center tube...but I dunno...these things defy "logic" sometimes...
Well I'm home sick today and playing with my Tundra. It's set up with a Johnson Controls 421 box switching the fan from speed 3 to speed 1 at 90f and back to speed 3 at 94f. Another 421 controller activates the fan at 115f and shuts down at 88f with a 3 minute anti short cycle delay. Temp probes are in the supply duct about 6" above the top of the stove.
My house is 1500sf with walk out basement, decent insulation in the walls and under insulated in the attic. It's currently around 10f outside and we've been in a cold snap for a couple days.
This furnace is struggling to say the least. It was 58 when I got up this morning and after burning a whole load of fuel it's 61 now. I'm burning 2-3 year split Honey Locust, Osage Orange, and a little Ash and Oak thrown in. The wood was stored on pallets, in the open, on asphalt for 2+ years and the last year or so kept on pallets under a roof. This is some primo fuel. With a full load of fuel, the fan only runs on speed 3 when the damper is open and the fire is glowing red. Otherwise, with the damper closed the fan is cycling. Is this similar to what your stoves are doing?
I have a third Johnson Controls box that I will use to operate the damper as soon as the replacement damper control motor comes. The first one failed after 2 weeks of use. It looks like the damper will need to open at 88f and close at 94f to keep the house warm in the cold weather. That's going to keep the damper open an awful lot and burn an awful lot of fuel. I'm anticipating a 2- hour burn per load which means a lot more tending to the stove than I had hoped for.
After investing the time and money to make this work, I'm feeling foolish. If I had it to do over again I'd buy the heatmax.
My house is 1500sf with walk out basement, decent insulation in the walls and under insulated in the attic. It's currently around 10f outside and we've been in a cold snap for a couple days.
This furnace is struggling to say the least. It was 58 when I got up this morning and after burning a whole load of fuel it's 61 now. I'm burning 2-3 year split Honey Locust, Osage Orange, and a little Ash and Oak thrown in. The wood was stored on pallets, in the open, on asphalt for 2+ years and the last year or so kept on pallets under a roof. This is some primo fuel. With a full load of fuel, the fan only runs on speed 3 when the damper is open and the fire is glowing red. Otherwise, with the damper closed the fan is cycling. Is this similar to what your stoves are doing?
I have a third Johnson Controls box that I will use to operate the damper as soon as the replacement damper control motor comes. The first one failed after 2 weeks of use. It looks like the damper will need to open at 88f and close at 94f to keep the house warm in the cold weather. That's going to keep the damper open an awful lot and burn an awful lot of fuel. I'm anticipating a 2- hour burn per load which means a lot more tending to the stove than I had hoped for.
After investing the time and money to make this work, I'm feeling foolish. If I had it to do over again I'd buy the heatmax.
Attachments
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?
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?
Last edited:
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.
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.
Should be no problem. Some wood furnace companys offer them as an option. Just wire it up the way they tell you (probably tap into the blower motor power I would guess)
sloeffle
Minister of Fire
Can you give us some more information on on how you have this setup ? @brenndatomu, is this the same setup you are using ?
Scott
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...
Last edited:
sloeffle
Minister of Fire
Sorry, I should've been more specific.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.
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...
Is this the controller you are using for your fan setup ?
Scott
No. I used a Totaline P251-0083H. ICM makes 'em I believe. ICM 325 or 333 IIRC
Last edited:
Similar threads
