First look at Drolet's new EPA 2020 wood furnace...

[aswr]

It's less than ideal to have two furnaces sharing ductwork AND running at the same time. Different static pressure will cause premature wear on the blowers if they are competing with one another. You'll also pull air backwards through the return when one furnace isn't running. I have mine set up with isolation dampers and an interlock. Flip the switch one way and the damper to the LP furnace / AC closes and the caddy is run by the home thermostats. Click it the other way and the Caddy is offline, it's damper closes and the LP furnace gets the signal. As to the intake damper on the Max Caddy, I agree. When it closes and your cruising, the secondaries die off fairly quickly and even a new call for heat 30 minutes later opening the damper back up doesn't bring them back. Now you have a slow burn until reload. For this reason, I'm considering pulling off my fresh air kit and doing a paper clip mod to prevent the intake damper from completely closing.

only one fan runs them both

 

[brenndatomu]

it is an add on and the 2 furnaces are competing against each other a bit. When the house is calling for heat and the geo kicks in it dampers down the max. Not liking that and not making much sense. Hvac guy going to change it to not damper down the max when geo kicks in until it hit 2nd stage.

Turn the geo tstat down so that if it does kick in, its toward the end of the burn on the Max...that way Max carries most of the load and you don't have to worry so much about overheating the Max...sounds like HVAC guy needs to rework some things for sure.

We set the plenum fan on temp at 130 and off at 100. Is that good for the unit?

Should be fine.

(If kuuma would csa cert i probably would have installed one of those. But because canada is not important to them, they don't.)

I don't know that they don't care about the Canadian market...more like they have their hands full getting things certified for their home market, what with the new 2020 certs required this year...EPA red tape nightmare it sounds like...heck, they still don't have their smaller VF200 certified yet! Plus all this testing is very expensive for a small family owned business, especially all at once!

When she is good and hot with the damper open and then dampers down i see the gasses burning but then shortly after it seems to stop

If that is happening in the early part of the burn (after the firebox is up to temp) then it sounds like the wood is not quite dry enough yet...secondary burn should self sustain once this are good and hot...at least until the wood is done gassing off and the cellulose starts to burn up more so (not going to have much secondary burn after 2, 3, maybe 4 hours (on a huge load)

 

[aswr]

only one fan runs them both

when the geo is calling 4 heat it auto closes the max damper. We still use a common plenum and a common blower fan to circulate heat through the house

 

[aswr]

Turn the geo tstat down so that if it does kick in, its toward the end of the burn on the Max...that was Max carries most of the load and you don't have to worry so much about overheating the Max...sounds like HVAC guy needs to rework some things for sure.

Should be fine.

I don't know that they don't care about the Canadian market...more like they have their hands full getting things certified for their home market, what with the new 2020 certs required this year...EPA red tape nightmare it sounds like...heck, they still don't have their smaller VF200 certified! Plus all this testing is very expensive for a small family owned business, especially all at once!

If that is happening in the early part of the burn (after the firebox is up to temp) then it sounds like the wood is not quite dry enough yet...secondary burn should self sustain once this are good and hot...at least until the wood is done gassing off and the cellulose starts to burn up more so (not going to have much secondary burn after 2, 3, maybe 4 hours (on a huge load)

wood is normally 18 - 20 % mc. the vf 100 uses the same wood from the same pile. We share both.

 

[laynes69]

In canada, a parallel install is illegal so it should be installed in series. If theres an interlock then both shouldn't run at the same time. I'm with brenn, you need to stop the call for heat from the geothermal so only the woodfurnace supplies the heat.

 

[aswr]

In canada, a parallel install is illegal so it should be installed in series. If theres an interlock then both shouldn't run at the same time. I'm with brenn, you need to stop the call for heat from the geothermal so only the woodfurnace supplies the heat.

you are right, my mistake the unit is in series

 

[aswr]

In canada, a parallel install is illegal so it should be installed in series. If theres an interlock then both shouldn't run at the same time. I'm with brenn, you need to stop the call for heat from the geothermal so only the woodfurnace supplies the heat.

the geo temp is set to kick in lower than the max temp. So when the max cant keep up the geo will kick in, usually at the beginning and end of the burn. It takes a long time for the max to increase the house temp after it drops a degree or two at wot. Once it gets there it will easily maintain temp without assistance. What should be the difference temp between the 2 units? 2 degree or 3?

 

[laynes69]

Our LP furnace is set at off. I will tell you running with the damper open, you're throwing heat out the chimney. I'll wake up at 72 degrees, load the furnace and open the damper. In about 10 to 15 minutes later close the damper and it cruises with the house increasing. Honestly it sounds like the house could use and/or insulating and sealing.

 

[aswr]

Our LP furnace is set at off. I will tell you running with the damper open, you're throwing heat out the chimney. I'll wake up at 72 degrees, load the furnace and open the damper. In about 10 to 15 minutes later close the damper and it cruises with the house increasing. Honestly it sounds like the house could use and/or insulating and sealing.

 

[aswr]

kind of hard to insulate?

 

[andym]

wood is normally 18 - 20 % mc. the vf 100 uses the same wood from the same pile. We share both.

In my limited experience with my Heatmax 2, 20% is plenty wet. 18% is alright but 15% is much better. You will struggle to keep secondaries burning at 20%. The reason (I stand to be corrected) the VF100 burns the same wood without issues is that its combustion is much more controlled. It has the ability to auto adjust the amount of air the fire receives. The new Drolet Heat Commander (OP here) also does this in a similar manner. That's why they are causing ripples of discontent among some of us with now outdated models! The older Caddys, Tundras, etc are either wide open draft or closed. Not the greatest system, but it works.

 

[laynes69]

kind of hard to insulate?
View attachment 269783

There's always improvements that can be done! Even airsealing will save alot of money. This is what I've dealt with over the years.

View attachment 269793

 

[usernametaken]

I will tell you running with the damper open, you're throwing heat out the chimney. the damper.

I wonder if the damper design difference between the Caddy and the Max is why we differ here. The Caddy has a hole in the damper door to allow some secondary air when cruising. The Max does not. I can tell you that when that damper is closed for any amount of time on the Max, it will hinder the burn and not keep the secondary burn going for long. When it reopens, the damage is done and you're not going to produce at a high level again until you reload. This is why I'm considering keeping it open just a hair so I get the same affect as the factory opening in your damper door.

 

[laynes69]

I use a paperclip to keep our damper open a hair. When its brutal cold, I don't need to use a clip because the damper cycles with the home. I can tell you from experience that the drier the wood the better.

 

[usernametaken]

Oh for sure. I'm at under 8% on my years supply in the basement. Last year (my first year here and poor supply due to building the house and having no dry storage) I was double or more. No bueno.

 

[brenndatomu]

This is why I'm considering keeping it open just a hair so I get the same affect as the factory opening in your damper door.

Does sound like the damper door needs to be cracked open a hair (paper clip trick)
Just so everybody is on the same page here...MC is checked by re-splitting the suspect wood and checking MC on the freshly exposed faces...pins with the grain, not across...and the wood should be be close to room temp too.
Checking the MC externally, especially on the end, means nothing.

 

[usernametaken]

Good tips brenn for those who don't know. It's nice when it's match light isn't it? I remember previous stoves that wood as dry as I have now would burn too quickly and I actually preferred wood that wasn't completely seasoned as it would give me the best overall performance. Modern appliances are a completely different story though.

 

[aswr]

I use a paperclip to keep our damper open a hair. When its brutal cold, I don't need to use a clip because the damper cycles with the home. I can tell you from experience that the drier the wood the better.

the max caddy damper has some sort of seal. where would you install a paper clip? Just to make sure. The max has 2 inlets on the bottom side of the door for pilot air, at least i think that is what they are for?lol

 

[usernametaken]

The bottom two are for primary air. The damper is for secondary. If you bend a paper clip and place it between where the damper closes and the frame of the stove, it will hold the damper open just slightly.

 

[aswr]

There's always improvements that can be done! Even airsealing will save alot of money. This is what I've dealt with over the years.

View attachment 269793 View attachment 269796

I have done all the doors and windows except the ones in the front. I havent had the courage to tackle those yet.

 

[usernametaken]

I have done all the doors and windows except the ones in the front. I havent had the courage to tackle those yet.

How does your ductwork run? I found one of my biggest issues at first was much of my ductwork was under insulated being outside the building envelope. Foam insulating made an enormous difference in heat loss on the way to the registers.

 

[aswr]

How does your ductwork run? I found one of my biggest issues at first was much of my ductwork was under insulated being outside the building envelope. Foam insulating made an enormous difference in heat loss on the way to the registers.

duct work is not insulated at all

 

[aswr]

The bottom two are for primary air. The damper is for secondary. If you bend a paper clip and place it between where the damper closes and the frame of the stove, it will hold the damper open just slightly.

any one have a diagram showing how the fresh air moves through the furnace?

 

[aswr]

duct work is not insulated at all

duct work is inside the building completely

 

[brenndatomu]

The damper is for secondary.

Damper is primary air...I know of no wood furnaces that control secondary air...can only think of one stove that has any control of the secondary air...but even it is tied to the same linkage as the primary air, so no individual control.