Another help me choose add on furnace

[Gbawol42]

Going to bring my post back from the dead.

Went with a heatmax for my final choice, still getting it hooked up for this season. Should be done here in the next 2 weeks.

Really liking the idea of the temp controller, could someone point out where in the forum there is more info on this, or PM if you have the time. Not an electriction by any means so looking at how to hook it up as well.

Any help is appreciated

Thanks

 

[brenndatomu]

Temp controller info in the big Tundra thread...link to it here. But this was all on the TI...T2 (Heatmax is same) is computer controlled, so things may be a bit different...still very doable though in my opinion. @Case1030 may be a source of info here too.

Tundra/Heatmax Information Guide

The purpose of this post is to help users quickly find information about the Drolet Tundra/Heatmax, for example operation of the furnace, typical temperatures, cracking problems, control improvements, and helpful hints. Even if you don’t own a Tundra/Heatmax, you may find helpful general...

www.hearth.com

 

[Gbawol42]

This thread has gone from me not even knowing what to buy, to finally doing my first burn in my new furnace.

Went with the drolet heatmax 2. So far so good, burning nice and hot, long burn times. However it's only just 40 degrees outside so we will see what happens when it actually gets colder.

All I have left to do is install the temp controller that I just got in the mail. Might also do the 30 minute timer that has been mentioned to more automate the process. Still trying to dial in the draft as well, only getting about .01, could be because it's not that cold out yet?

Thanks for all the help over the last 2 years everyone, it was greatly appreciated!

Also that chimney is 36 feet, I'm sure some of you were going to ask.

 

[brenndatomu]

Congrats!
So you only have -0.01" draft, or -0.1"?
0.01 is pretty low...even at 40*, especially with a tall chimney. I would be surprised you could even get the furnace to burn well with 0.01
-0.1" would be more expected with a tall chimney...and then they can be hard to control when the weather gets real cold

 

[Gbawol42]

Congrats!
So you only have -0.01" draft, or -0.1"?
0.01 is pretty low...even at 40*, especially with a tall chimney. I would be surprised you could even get the furnace to burn well with 0.01
-0.1" would be more expected with a tall chimney...and then they can be hard to control when the weather gets real cold

Mistype, 0.1 is what it was supposed to be. That was this morning when it was a little cooler. I'm actually sitting at .05 right now.

Only been burning 3-4 splits at a time as I didn't want to overheat the house. Been sitting between 68 and 70 degrees in the home, and like I said it was 37 this morning and snow/rain. Now it's around 45 degrees outside. Yay northern michigan! Haha

 

[brenndatomu]

The -0.06" you have in the pic there is max recommended draft...as I'm sure you know. (they still call for -0.04" to -0.06" I would guess?) So -0.10" is way too high and will cause overheating of the furnace. Do you have a barometric damper installed? With a 35' tall chimney 1 might not be enough...I've heard of people that had to install 2! Personally I think I would just install a manual damper downstream of the baro...when it gets real cold and windy and the baro can't keep up, then close the manual damper enough that the baro can do its job without being wide open all the time. Just have to remember to open the manual damper before reloading...makes for smoke in the house if you don't
I had a manual damper in addition to the baro before...changed my stove pipe setup last year and didn't put it back in because I hardly used it...guess what happened last winter...real cold spell came along and I needed it! Its going back in right now...got some purty SS stove pipe I'm installing this weekend

 

[Gbawol42]

The -0.06" you have in the pic there is max recommended draft...as I'm sure you know. (they still call for -0.04" to -0.06" I would guess?) So -0.10" is way too high and will cause overheating of the furnace. Do you have a barometric damper installed? With a 35' tall chimney 1 might not be enough...I've heard of people that had to install 2! Personally I think I would just install a manual damper downstream of the baro...when it gets real cold and windy and the baro can't keep up, then close the manual damper enough that the baro can do its job without being wide open all the time. Just have to remember to open the manual damper before reloading...makes for smoke in the house if you don't
I had a manual damper in addition to the baro before...changed my stove pipe setup last year and didn't put it back in because I hardly used it...guess what happened last winter...real cold spell came along and I needed it! Its going back in right now...got some purty SS stove pipe I'm installing this weekend

Been doing to much lately I guess, I had .2 stuck in my head as i was doing my heating ducts a little bit ago. So my draft is actually doing well, for now. I haven't really dialed in the baro yet so I suppose time to mess with that. Hopefully I don't have the need for 2, wouldn't be difficult to install if it was needed.

I was only seeing the .1 when the wind would gust really hard, came back when the wind stopped. Had quite the wind storm last night and this morning.

 

[brenndatomu]

If you have a Fields baro then you should be able to set it by the numbers behind the adjustment knob...that will get it close anyways...use your manometer to confirm.

Seeing .1 during wind gusts with a 35' chimney is not surprising. You don't want the draft to stay that high very long though...

 

[Mrpelletburner]

Nice setup [emoji106]

 

[Gbawol42]

Is the raking the coals to the front for reloading something that should be applied to all furnace reloading? Or is it just a Kumma thing? Just curious

 

[3fordasho]

Is the raking the coals to the front for reloading something that should be applied to all furnace reloading? Or is it just a Kumma thing? Just curious

Yes, I do it with my Tundra on every reload on coals. The pilot air right in front under the loading door directs air onto the coals making for a quick restart.

 

[brenndatomu]

Works good in the Tundra too...

 

[Gbawol42]

Ok time for the diagnosis post.

I have my temp controller installed and it is telling me some things about how my wood is burning that I really couldn't tell before. The big one is my flue is not really heating up that much.

1. I now believe that my wood isn't ideally dry. Went and got a moisture meter and checked a few splits on a fresh face and I am sitting at around 22-25 on most is seems. I thought I would get away with one year drying since I had it in one long row however the wet spring and fall we had here in michigan did not help my situation. I am going to make a decision to either supplement with eco bricks or just burn propane since it's only around $1.25-$1.35 a gallon right now.

2. This is where I might need input. I have the temp controller plugged about 8 inches above the rear flue opening of heatmax. I set the temp controller at 250F to reopen the damper and burn down my coals. However when I loaded the stove with 4 splits (wasn't that cold out) I couldn't get the flue temp over 220F-230F. So basically the damper never wanted to shut off. The stove magnetic gauge never went above 350F-400F, I have that located just to the left of the dampener on the front of the stove. I inferred thermometer the single wall stove pipe and it sat just above 200F. Does this sound right to you guys? I feel like I am missing something or have something not hooked where it is supposed to go. Or do these stoves just not heat up all the way when partially loaded?

What do these stoves range in flue temps when the are loaded and when they are at idle?

If I missed something or you need more info or pictures just ask.

Thanks in advance guys.

 

[brenndatomu]

Is your temp controller reading C or F?
If you are reading 200*F externally on the pipe, the internal temp should be 400, or a bit more...my guess is something is not right with the controller settings, or the TC is goofy.
It should burn 22-25% MC wood "sorta OK", not great, but OK...you probably will not see extended secondary burns...especially with only 4 pieces of marginal wood in it.
Depending on your chimney, you may not have "great" draft until the temps drop a little more (unless its been colder there?) that will affect the way it burns too.
As you have found out, until you can get the firebox up to temp, on dry wood, and the intake damper closed, the heat output is "meh".
As far as temps go...I had a mag thermometer on the HX cleanout door and it would run in the 350* range (IIRC, I haven't run the ole Tundra since winter '16-'17, so this is all from rusty cobwebs memory) and my internal flue temps would hover in the 300's for the first couple hours...I had my controller set to close the damper at 350*, and reopen at 300* (if there was still a call for heat) and it would usually only cycle once after a re-load...then the temp would stay over 300 on its own running on just pilot air, and the timer was usually timed out by then anyways....but this was all burning 3-4 year CSS wood too.
Oh, make sure the baffle above the secondary burn tubes is sitting in place properly, and slid back against the back bricks (doesn't hurt to check this once in a while either...it can be dislodged with a split, and if out of place it makes a big difference in the way things work!)

 

[brenndatomu]

If you want to burn small loads, split those splits in half and put them in loosely, as high as possible, log cabin style works too...it will burn small loads better that way. Makes a good "shoulder season" fire. Starting with burning down a small load of kindlin (almost down to hot coals) and then load the splits on that, can make things run more normally too...

 

[Gbawol42]

Is your temp controller reading C or F?
If you are reading 200*F externally on the pipe, the internal temp should be 400, or a bit more...my guess is something is not right with the controller settings, or the TC is goofy.
It should burn 22-25% MC wood "sorta OK", not great, but OK...you probably will not see extended secondary burns...especially with only 4 pieces of marginal wood in it.
Depending on your chimney, you may not have "great" draft until the temps drop a little more (unless its been colder there?) that will affect the way it burns too.
As you have found out, until you can get the firebox up to temp, on dry wood, and the intake damper closed, the heat output is "meh".
As far as temps go...I had a mag thermometer on the HX cleanout door and it would run in the 350* range (IIRC, I haven't run the ole Tundra since winter '16-'17, so this is all from rusty cobwebs memory) and my internal flue temps would hover in the 300's for the first couple hours...I had my controller set to close the damper at 350*, and reopen at 300* (if there was still a call for heat) and it would usually only cycle once after a re-load...then the temp would stay over 300 on its own running on just pilot air, and the timer was usually timed out by then anyways....but this was all burning 3-4 year CSS wood too.
Oh, make sure the baffle above the secondary burn tubes is sitting in place properly, and slid back against the back bricks (doesn't hurt to check this once in a while either...it can be dislodged with a split, and if out of place it makes a big difference in the way things work!)

That's what I thought, it was double the inferred to get approx flue.

The TC is in celcius, I just bought a cheapo from good ol china. Perhaps I need to test the probe. It appeared to be reading correctly before I lit the stove though.

I know the stove will run better with dryer wood, I just wanted to see if I had something not set right. Probably need to check more settings on this TC. I just set the bare minimum. I am going to have to look into how you set yours up. I just hooked mine into the thermostat connection on the stove. One relay, just on and off at a certain temp, will need to see how to did a range. One of the main reasons for it was if I loaded the stove before work and set the timer for 20 or 30 min (depending on how many coals were present) and the fire didn't get hot enough and smoldered out, the TC would open the dampener for me and heat it back up. Just trying to make it through that crucial cresote making stage since I have less than ideal wood. It will be a little easier when I am home to check the stove more.

I'll be honest I am still having fun burning wood, kind of a neat mental game figuring everything out.

 

[brenndatomu]

So that is 200C? That would be 392F.
How long is the TC probe? If it is short I would move it to the front of the pipe to try to get in the exaust stream as much as possible. I have a 6" TC probe and found out that if I stick it all the way in on my horizontalish stove pipe it reads way low. Pull it up/out 2-3" the temp reading jumps up.
If you are tied into the tstat terminals you are using the controller in a different way than I was. I had it set up to interrupt the call for heat from either the tstat, manual switch, or the timer. So acted as a true high temp controllr...and never did set it up to burn down coals. I had the luxury of firing up the stove in the fireplace if I needed more heat, so no real need to push the Tundra to the point of coal build up. Sounds like you could just fire up the LP to make up the difference if you needed to.
And yes, it is kinda fun figuring this stuff out...as long as you can actually get it to work at some point...early on I was about ready to boot my T1 out permanently!

 

[Mrpelletburner]

What is the temperature of your basement around the distribution blower intake?

Just wondering if you are drawing in cooler air. As the cooler air can impact plenum and flue temps.


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[Gbawol42]

What is the temperature of your basement around the distribution blower intake?

Just wondering if you are drawing in cooler air. As the cooler air can impact plenum and flue temps.


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Now this is something I wasn't taking into consideration! I'm probably sucking lower 60 degree air from my basement floor. Might have to look into putting a return duct up to the ceiling where the air is warmer. I would tie into my main return system but it's kinda far from the wood stove and wouldn't be cheap.

 

[brenndatomu]

The cold air from down low will affect the supply duct temps some, especially in the cold parts of the winter, but will make very little/no difference in the chimney temps...

 

[Mrpelletburner]

The cold air from down low will affect the supply duct temps some, especially in the cold parts of the winter, but will make very little/no difference in the chimney temps...

Why would that cooler air make very little to no difference to flue temps? Just asking...




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[maple1]

Why would that cooler air make very little to no difference to flue temps? Just asking...




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Likely talking in terms of 'negligible'.

A 10 degree drop from say 100 to 90 in supply temps would be more a more pronounced and notcieable difference than say a 10 degree drop from 380 to 370 (or whatever) in flue temps.

 

[brenndatomu]

Why would that cooler air make very little to no difference to flue temps? Just asking...




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Well, I would say its kinda like spraying a garden hose on a forest fire...just not gonna make any difference.
If you think about it, 10-20* less going into a 12-1500* (more?) fire is nothing...might even make up for the temp loss completly by burning a bit hotter due to cooler air being more oxygen dense.
But the furnace is only raising the return air temp 40-70* going into the supply ducts, so 10-20* less coming in is a big deal.

 

[Highbeam]

Also remember that unlike a stove, these warm air furnaces are built with a massive back and forth heat exchanger in the flue gas path which is not unlike the old "magic heat" flue gas heat reclaimers that so many people hate from the old days. This heat exchanger is designed to strip heat from the flue gasses.

It's a good idea but it will lower the flue gas temperatures from what you may be familiar with when running a stove. You still want to be sure that you are keeping above the condensation temperature in the flue. That may mean adjusting the blower speed or keeping a hotter fire.

 

[Gbawol42]

How about a dampener question for you guys.

I currently have 2 direct outputs (1 to main living room, and 1 to upstairs master), and 4 outputs to my heating trunk to heat the rest if the house. I have a gravity dampener in the plenum of my propane furnace so the heatmax will not blow into it, as well as the propane furnace could open it anytime it runs as the fan is stronger. On the 4 outputs to the heat trunk from the heatmax I have 4 manual dampener installed. My thought process was if I wanted to use the propane during the shoulder season I would just close those 4 vents and that should be good to not backfeed the heatmax.

So i am now thinking about running the unit in parallel with the propane furnace. Was looking into 4, 6" gravity dampener for the heatmax. My question is what happens when the heatmax is nice and hot and the propane furnace kicks on, say under a really cold day. If the gravity dampeners close on the heatmax won't the plenum overheat? Grant it I still have the 2 direct connects. Am I thinking about this right, or would you guys plumb up the ducts differently? Or would the way I am thinking be ok and not overheat?