Everything Drolet Tundra - Heatmax...

[maple1]

Great points! The damper switch could be relocated... heck I could probably mount it on the wall or on the sheet metal surround. That would look nice.

I’m sure some proper engineering could keep the sheet metal surround quiet.

I would not expect having the damper in one room and combustion air in another room to cause an issue. If a shortage of combustion air became an issue, it would certainly be harder to deal with in a way that looked good.

I may have to call SBI and see what they say. This would likely be a spring or summer project, as I need to keep this thing running right now. (Although it was like 50+ degrees today and I cut some wood in a tee shirt)

I have also thought about installing a few “thru wall” or “transfer” fans and control them via a manual switch and the temp controller. The fans would be installed near the furnace and pull the air off the front of the stove, thru the wall, and into the living area. I don’t want to rob the furnace of combustion air though... not sure if that could be an issue.

Couldn't that be accomplished by ducting, and routing of supply & return air?

Pull return from your furnace room? Send a supply to outside of it?

As long as it didn't mess up your draft situation, of course.

What is your duct & return situation? (Might have been posted & I missed it).

 

[Boilers]

Couldn't that be accomplished by ducting, and routing of supply & return air?

Pull return from your furnace room? Send a supply to outside of it?

As long as it didn't mess up your draft situation, of course.

What is your duct & return situation? (Might have been posted & I missed it).

My supply duct situation isnt great. I sized everything for 1400 CFM, which is what Drolet marketing says the furnace will do, however the blower has 4 speeds and generally runs on speed 1, which is 900 CFM. From the furnace, I have about 10' of 14" round, going into the main trunk which runs from end to end of my house. The main trunk is 58' long. I then have 15 takeoffs from the main trunk. The takeoffs are all 6", but I have 3 registers completely closed and many of them partly closed. Currently the static pressure is about 0.04" WC. Including the main trunk, I have ~250' of duct! Most of the duct is metal. Some secondary runs are 6" insulated flex. Currently, I have been working on sealing the duct and I have also purchased some insulation to install over the duct. During initial firing, when plenum temps are ~150, and blower is on speed 2 (1000 CFM), I have seen 113 degrees at registers close to the furnace. The furthest registers never break 100 degrees. During normal operation, most registers are in the low to mid 90's, with the furthest registers being in mid to low 80's.

The return air is a Y. 3' of 12x24 duct into my house return air and 4' of 10x24 into the furnace room. I did this because I dont want to pull too much of a vacuum on my furnace room, since there is a garage door and a couple other spots where cold outside air could be drawn inside. While some fresh air is good, drawing cold air inside is counter productive to heating purposes.

 

[brenndatomu]

. During initial firing, when plenum temps are ~150, and blower is on speed 2 (1000 CFM), I have seen 113 degrees at registers close to the furnace. The furthest registers never break 100 degrees. During normal operation, most registers are in the low to mid 90's, with the furthest registers being in mid to low 80's.

This will heat your house. If you look back through this thread you will find that my Tundra rarely broke 120* (125* for sure) plenum temps.
And the way I have the Kuuma set up, its the same way...117* is about as hot as it gets...heats the house just fine.
If you see 150* at the plenum I'd be running the blower on a higher speed...or get a less restrictive filter on the blower.
Ideally, putting a speed controller on the blower would help the most...blower can run wide open when the heat is there, then later on in the burn it can run low and slow all the way to the end.

 

[Boilers]

This will heat your house. If you look back through this thread you will find that my Tundra rarely broke 120* (125* for sure) plenum temps.
And the way I have the Kuuma set up, its the same way...117* is about as hot as it gets...heats the house just fine.
If you see 150* at the plenum I'd be running the blower on a higher speed...or get a less restrictive filter on the blower.
Ideally, putting a speed controller on the blower would help the most...blower can run wide open when the heat is there, then later on in the burn it can run low and slow all the way to the end.

I dont see 150 degree plenum for long... only for a few minutes on a new load right before I try to close the damper for the first time. maybe 10 minutes. Once I close the damper, temp will creep its was back down to 125 or so and stay there until the secondaries go out. If secondaries go out, the blower cycling begins soon after (ie. Coaling stage or fire didnt take)

 

[Boilers]

Temp controller is installed and working beautifully. I don’t have a timer at the moment, and I realized pretty quickly why you all have one! It took 3-5 cycles before the fire would actually stay lit. At one point I was quite scared of an explosion, because the fire box had gotten full of smoke and the damper finally kicked open. It poofed a little but not bad.

Now I have to dial it in... I currently have AL1 setup as PV Low Alarm. It’s set at 310 deg with hysteresis of 100. So if temp gets below 310, relay closes and damper opens until temp gets to 410. I will make the hysteresis lower once I get a timer installed... without the big hysteresis it would cycle like crazy during startup. I kind of have the hardware temporarily rigged. I’ll get an enclosure and pretty it up soon.

 

[brenndatomu]

without the big hysteresis it would cycle like crazy during startup

Yes, the timer is key to making this "load n go".
IIRC, I had a 50* hysteresis and it would only cycle once, maybe twice after a hot reload. 350* high/300* low
Edit: now I am questioning myself...maybe the low setting was 250...guess I could scroll back through this thread and find out, huh?!
Edit the Edit: Yes it was 250 on the low setting

 

[Boilers]

Yes, the timer is key to making this "load n go".
IIRC, I had a 50* hysteresis and it would only cycle once, maybe twice after a hot reload. 350* high/300* low
Edit: now I am questioning myself...maybe the low setting was 250...guess I could scroll back through this thread and find out, huh?!
Edit the Edit: Yes it was 250 on the low setting

Funny... I was looking back through this thread last night trying to find your settings! you were pretty conservative at 250/300. I dont know that 250 would work for me. I was losing secondaries at ~290 ish. Im sure this value will vary from one fire to the next. It was also 50 degrees outside, so draft could have been a little low, additionally the fire I build was small. I will continue to play with it. By the time I was done playing with the controller last night, I had it set at 295/345.

By the way... holy cow! Internal flue temps are nearly double what my IR gun was reading on the outside of the single wall stove pipe, 12" outside of the furnace! So that one time when I saw 400+ degrees on the outside..... (probably truly only 650-700 on the inside, but still!)

Here soon, I will draw an electrical schematic for the controls and upload it for everyone.

 

[Highbeam]

By the way... holy cow! Internal flue temps are nearly double what my IR gun was reading on the outside of the single wall stove pipe, 12" outside of the furnace! So that one time when I saw 400+ degrees on the outside..... (probably truly only 650-700 on the inside, but still!)

That's totally expected. The skin temperature of single wall pipe is only approximately half of internal gas temperatures. That said, 400 external is not too hot. It corresponds with 800 internal and Class A is rated for 1000 degrees continuously.

 

[Boilers]

For all those interested, I am working on a new control system for my Heatmax II. Since I am an automation engineer, and a bit of a geek, I decided its appropriate. Basically I will have 16 output relays, 16 inputs, 8 analog inputs and 8 analog outputs. The possibilities will be endless!

 

[JRHAWK9]

For all those interested, I am working on a new control system for my Heatmax II. Since I am an automation engineer, and a bit of a geek, I decided its appropriate. Basically I will have 16 output relays, 16 inputs, 8 analog inputs and 8 analog outputs. The possibilities will be endless!

freakin' sweet!!

 

[sloeffle]

Any idea on cost ?

 

[Boilers]

Any idea on cost ?

I highly doubt it makes sense for me to do this... not with the equipment I am using. You could likely buy an Automation Direct PLC, with the Inputs and Outputs you need for relatively cheap. These controllers are not really industrial (my opinion), so we dont use them at work, but I know some places do. I've heard good reviews. The software is free also! For someone unfamiliar with PLC's, this might not be for you, but theres tons of video tutorials on these. Biggest thing is to make sure you do things safely. Put the controller/relays, power supply's in an enclosure and be sure to fuse anything that consumes power.

This would probably work: https://www.automationdirect.com/ad...s_(stackable_micro_brick)/plc_units/c0-02dr-d

 

[Case1030]

Are barometric dampers useful on short chimneys (15-16ft).

Been having a few windy days here, usually on calm and warm days I have to add a nail to keep my air intake open a bit (like others with shorter chimneya) to maintain good secondarys. I might have to put a baro in to save fiddling around, but am worried it will rob chimney draft on the warm or calm days.

Also flue temps run around 350f on the average day for my unit. After a reload this morning with high winds it was sitting at 500f.

 

[Boilers]

Are barometric dampers useful on short chimneys (15-16ft).

Been having a few windy days here, usually on calm and warm days I have to add a nail to keep my air intake open a bit (like others with shorter chimneya) to maintain good secondarys. I might have to put a baro in to save fiddling around, but am worried it will rob chimney draft on the warm or calm days.

Also flue temps run around 350f on the average day for my unit. After a reload this morning with high winds it was sitting at 500f.

I cannot comment for your specific situation, but my flue is 23FT straight up and 2 FT horizontal. On a calm cold day, the draft can be high. 0.8-1.0 in vacuum. Cold and windy, Ive seen it spike over 2.0 and maintain 1.2. I then installed a field logic baro and watched it closely for a long time. It has performed so well, that I barely even look at it any more, other than the occasional once over to make sure it doesnt get clogged caught up on creosote.

 

[Mrpelletburner]

other than the occasional once over to make sure it doesnt get clogged caught on creosote.

So creosote build up is normal on the back of a baro?

 

[Case1030]

I cannot comment for your specific situation, but my flue is 23FT straight up and 2 FT horizontal. On a calm cold day, the draft can be high. 0.8-1.0 in vacuum. Cold and windy, Ive seen it spike over 2.0 and maintain 1.2. I then installed a field logic baro and watched it closely for a long time. It has performed so well, that I barely even look at it any more, other than the occasional once over to make sure it doesnt get clogged caught up on creosote.

Isnt there always a little air going up the chimney with a baro (not perfectly sealed around the flap)?

 

[Boilers]

So creosote build up is normal on the back of a baro?

Its normal for me! Im newer to burning wood though. I have been super careful about creosote because of this. Ive cleaned my heat exchangers and the flue twice this year. I know my wood isnt fully seasoned, so it gives me peace of mind. Ive had minimal buildup in the firebox. The heat exchangers have been caked in 1/8" of creosote, sort of like a dry paste. Ive also noticed the back of the baro has more of a tacky coating on the back of it and a little on the T. Other than this, Ive swept the flue twice and each time I probably got 2 cups of completely dry material.


Yes Case1030, theres is always some air going through the baro, even when the baro is closed.

 

[JRHAWK9]

Isnt there always a little air going up the chimney with a baro (not perfectly sealed around the flap)?

yes, not only is the flap not sealed but most of the time the flap is actually partially open, and can be open a fair amount depending on conditions.

 

[laynes69]

Are barometric dampers useful on short chimneys (15-16ft).

Been having a few windy days here, usually on calm and warm days I have to add a nail to keep my air intake open a bit (like others with shorter chimneya) to maintain good secondarys. I might have to put a baro in to save fiddling around, but am worried it will rob chimney draft on the warm or calm days.

Also flue temps run around 350f on the average day for my unit. After a reload this morning with high winds it was sitting at 500f.

I wouldn't do it. You'll have windy days, but a baro doesn't completely close, so it would spoil your draft. Especially when the fire does down, you will still have plenty of draft without a baro.

 

[brenndatomu]

I might have to put a baro in to save fiddling around, but am worried it will rob chimney draft on the warm or calm days.

You'll be fine...on a warm day if the draft is below -0.06" (or whatever you set it at) then the baro wont open...or very little anyways...it will maintain 0.06 as long as you have enough heat in the chimney to do so...it will not rob draft.
Put one in and try it....is easy to pop off and cap the tee if you don't like it...or you could do what I did...just cover it with some HD aluminum foil on days that you don't want to use it...that's what my sister does on their Tundra baro with a 15' chimney...works out great.

 

[sloeffle]

Do you guys find that you get longer burn times when you push the wood to the back of the stove vs having it a few inches from the front ? Most of my wood is 16" long.

 

[brenndatomu]

Do you guys find that you get longer burn times when you push the wood to the back of the stove vs having it a few inches from the front ? Most of my wood is 16" long.

I always shoved stuff back as far as I could, but I didn't have anything under 20" though either...usually left a few pieces out to the front on the coals to get things going.

 

[Case1030]

False alarm guys. I thought it was the wind draft screwing me around with the high flue...

I feel like an idiot, a couple days ago forgot to push the baffle from the front of the firebox after I did my monthly heat exchanger clean out.

I was really confused because high wind have only ever brought my flue from 350- 400f at the most. I guess I wont be needing a baro after all.

 

[3fordasho]

False alarm guys. I thought it was the wind draft screwing me around with the high flue...

I feel like an idiot, a couple days ago forgot to push the baffle from the front of the firebox after I did my monthly heat exchanger clean out.

I was really confused because high wind have only ever brought my flue from 350- 400f at the most. I guess I wont be needing a baro after all.

I've got the same chimney height and a couple times every heating season when I get high enough winds from the south (no tree protection from that direction) I will see 500F+ flue temps. Otherwise 350-400 is normal for me as well. During those relatively rare events I remove the paper clip that holds the air inlet slightly open and use aluminum tape to reduce the openings for secondary air by about half to tame things down a bit. I did purchase a BD and probably should install it but so far have not. The extra flue temp during these events also increases plenum temps and with no tree protection from the south the house needs the extra heat.

 

[sloeffle]

I highly doubt it makes sense for me to do this... not with the equipment I am using. You could likely buy an Automation Direct PLC, with the Inputs and Outputs you need for relatively cheap. These controllers are not really industrial (my opinion), so we dont use them at work, but I know some places do. I've heard good reviews. The software is free also! For someone unfamiliar with PLC's, this might not be for you, but theres tons of video tutorials on these. Biggest thing is to make sure you do things safely. Put the controller/relays, power supply's in an enclosure and be sure to fuse anything that consumes power.

This would probably work: https://www.automationdirect.com/ad...s_(stackable_micro_brick)/plc_units/c0-02dr-d

I took Allen Bradley PLC classes many moons ago ( 2000ish ) in college. I work on computers for a living now so I’m familiar with writing code. I thought about hooking a Raspberry Pi up but I don’t think it would be ideal to use for this type of thing.

Thanks for the link. I’ll take a look.