Finally pulled the trigger

[fields_mj]

I finally did it. I finally ordered a Heat Commander to replace my 1980 Energy Mate add on wood furnace. Northern Tool still has (or had) them listed at $3400 + tax and shipping which brought the total to just over $4100. I'll still need to purchase a few accessories for it, but I want to get it set in place and then see what's needed instead of buying a bunch of stuff that isn't right.

Next priority will be clearing a path through the house and basement so that I can get the old energy mate out and get the new unit set in place once it arrives. Then it will be a matter of figuring out who I can con into helping me get them moved.... lol

 

[fields_mj]

Well, the furnace finally arrived a few weeks ago. No big deal, I wasn't in a rush. I've been piddling around getting the crate broken down and getting it set up for a couple of test burns before I start working getting the old unit out and getting this unit taken to the basement. This past Saturday I put the plenum on it, and went to install the RTD, but couldn't find it. Monday was a wash with the holiday, so I called yesterday. They let me know that the RTD should have been with the manual, and asked that I get the warrantee information submitted before going any further. I wrote down the the SN last night, and then filled out the information on line this morning. As soon as I had that submitted, I called their tech support line to see what I needed to do about the missing RTD. SUPER helpful guy. He got me squared away, and got a new RTD enroute for me. So far Drolet gets a +1 for customer service. We'll see how the rest goes, but these days its really encouraging to get good customer support from a person that's very easy to understand.

 

[fields_mj]

Well, it only took 3-1/2 months, but its finally done (almost). Still have to wire in the new thermostat. The wire is run, just need to make the connections on both ends. Realistically, it sat in the garage most of that time waiting for me to finish other projects (including cutting firewood). It's been in the basement for about 4 weeks, but progress was delayed due to deer season

I ordered their cold air return filter housing. It was easy enough to bolt on, but IMHO it's poorly designed. The housing moves the filter out past the side of the furnace, but for some reason still requires the filter to be removed from the rear. IMHO, it should have been designed to have the filter removed from the top or towards the front. That's the only reason I can think of to shift the filter out past the side of the furnace. I made some mods so that I could do exactly that since there's obviously no room to remove the filter towards the back of the unit.

Had a local HVAC company do the plenum. Prior to receiving the furnace and reading the manual, I didn't realize they expected you to use at least 6 of the 6" duct connections. I'm using this as an add-on system, so making 6 connections wasn't going to work. Thankfully, the HVAC company had bugered up some of my existing plenum work this summer when they replaced my A Coil (didn't realize it until I started looking at how I wanted this furnace installed). They didn't credit me anything for the work they messed up over the summer, but the new stuff they installed also replaced what was messed up so its all sealed up now. My wife even likes the way it looks. The old unit was an Energy Mate from 1980, so the bar was set pretty low LOL. The weather has finally cooled of to more seasonable weather, but it hasn't been cold enough to use it yet. Looks like late next week the highs will finally drop down into the 30s, so we'll get a chance to try it out. Guess I will need to bring some firewood in between now and then...

 

[brenndatomu]

Well, it only took 3-1/2 months, but its finally done (almost). Still have to wire in the new thermostat. The wire is run, just need to make the connections on both ends. Realistically, it sat in the garage most of that time waiting for me to finish other projects (including cutting firewood). It's been in the basement for about 4 weeks, but progress was delayed due to deer season

I ordered their cold air return filter housing. It was easy enough to bolt on, but IMHO it's poorly designed. The housing moves the filter out past the side of the furnace, but for some reason still requires the filter to be removed from the rear. IMHO, it should have been designed to have the filter removed from the top or towards the front. That's the only reason I can think of to shift the filter out past the side of the furnace. I made some mods so that I could do exactly that since there's obviously no room to remove the filter towards the back of the unit.

Had a local HVAC company do the plenum. Prior to receiving the furnace and reading the manual, I didn't realize they expected you to use at least 6 of the 6" duct connections. I'm using this as an add-on system, so making 6 connections wasn't going to work. Thankfully, the HVAC company had bugered up some of my existing plenum work this summer when they replaced my A Coil (didn't realize it until I started looking at how I wanted this furnace installed). They didn't credit me anything for the work they messed up over the summer, but the new stuff they installed also replaced what was messed up so its all sealed up now. My wife even likes the way it looks. The old unit was an Energy Mate from 1980, so the bar was set pretty low LOL. The weather has finally cooled of to more seasonable weather, but it hasn't been cold enough to use it yet. Looks like late next week the highs will finally drop down into the 30s, so we'll get a chance to try it out. Guess I will need to bring some firewood in between now and then...

View attachment 342396

When you dropping a match in 'er?!
As far as the 6 duct connections...I wouldn't sweat that, as long as your total duct capacity is close to, or over 170 sq inches...which if that duct coming off the top there is your only connection, it would need to be a 15"...is it that big? Hard to tell from the pic.
I made my own filter brackets too...also out the top.

 

[fields_mj]

I put the first match to it the day before thanksgiving, and there was a problem. When I plugged the unit in, the G servo motor runs continuously. I can hear the plat fall shut ever 10-20 sec. Customer support was friendly and easy to understand. They thought the limit switch probably wasn't getting made when it closed so the servo couldn't find its starting point. I metered out the connections at the board, and the circuit does close when the plate engages the limit switch so that's not what's happening. By that point it was already 5:30 in the afternoon so I had to wait until today to call them back. They want me to check the firmware rev to make sure it's not something that has a bug in it. I'll check that tonight and work from home tomorrow so that I can trouble shoot it while their tech support line is open. Other than that,

Unfortunately, no, that duct is not 15". Its only 12" I'm more than a little frustrated about that since I paid the local H&AC company a small fortune to design, fabricate, and install that plenum, we specifically spoke about the 6-10 6" ducts and the corresponding 170 sq in minimum, AND I sent him away WITH my owners manual so that he had all the information right there handy. With that said, my old unit (kind of like an old Clayton clone) only had a single 10" round outlet (79 sq in), and I normally ran it with the 6" flew draft open about 2" and no barometric damper. I ran it that way for almost 20 years with no problems. It would heat the house just fine on its own down into the -10 to -15 range so long as I kept it fed. I think the HC with a barometric damper will be MUCH safer even with the single 12" (113sq in) outlet. I'll run it this season and see how it does. If there's a problem, I'll add another duct and see how it does next season.

Thinking through it, having a smaller outlet could have 3 effects. 1 - put extra strain on the blower. I don't think this is a big issue myself. Squirrel cage blowers are pretty durable in that regard. 2 - reduce the amount of heat available for the house. This would mean that it would take longer to for the unit to raise the house temp the few degrees required by the thermostat which would cause the blower to run longer. This is actually desirable IMHO. I would prefer the blower to run all the time when its actually cold out (below freezing). Ideally, they would have supplied a thermostat with the unit that would have fed an analog signal back to the CPU, which would have had a PID program that calculated the required furnace temp to maintain the house at the selected temperature. That would mimic what I was doing manually with the old unit, but alas, its not how the system actually works. Either way, if my old unit could keep up with a 10" duct, I'm confident that this one can keep up with an outlet that's 50% larger, and a more efficient heat transfer system. 3 - It would reduce the system's ability to recover from an over temp condition. This is the one that concerns me more, but not a lot. Because my old system was very manual, I am accustomed to building fires that match the weather conditions. Additionally, I installed a barometric damper with this unit which drastically reduces the draft that my 24' chimney produces. Those two should eliminate this issue, but my strategy is to go slow and work my way up just the same.

 

[begreen]

Maybe put a 4x10 register on the plenum face to dump some heat into the basement? Or add a 6" supply duct to some part of the house?

 

[brenndatomu]

Unfortunately, no, that duct is not 15". Its only 12"

Believe it or not, that's a huge difference in capacity...about a 1/3 reduction...176 cu. in. VS 113, or equal to about 2.5 of those 6" ducts they talk about.
This reduction in size will not put extra strain on the blower, it will actually be less strain...the less air a centrifugal blower moves the less power it uses.
You are correct though that it will not "cool" the furnace as well, which is one of the reasons that SBI increased the required duct size from ~100, to 170. (Tundra to HC...they claim the Tundra crack issue was at least in part from overheating)
If you ever hear the blower kick up to high speed, the computer has sensed that the plenum temp is too high...so either the draft is too high, or it's time to add more duct capacity. (or the filter is plugged)

Good luck with getting the glitch sorted out, every time I've heard of the dampers doing that repetitive kachunk kachunk thing, the tab needed adjusted on the limit switch. But SBI is good to work with, they'll get you taken care of.

 

[fields_mj]

The other piece of the equation is that I normally run the central air blower all the time to keep the air circulating in the house. Maybe the contractor contacted SBI and they told him to do it this way. Either way, its something I'm going to pay attention to. If need be, I'll vent to the basement. I may also add a inlet to my central air cold air return to better circulate the heat from the basement to the rest of the house to maintain a more stable temperature. Have to wait and see how things work out once the glitch is resolved.

 

[fields_mj]

Some success! I'm now able to get the main blower to come on when I need heat. I wasn't running the furnace hot enough. I thought that the green light on meant that the furnace was ready to supply heat, and on solid meant that the thermostat was also calling for heat. Turns out, the green light has nothing to do with the RTD thermocouple in the plenum, and the blower won't kick on until the RTD reads 130 degrees (about 150 ohms of resistance).

The damper on my grate is still cycling continuously, but at least the blower is now operational.

 

[Laynes6999]

On the advanced caddy, a solid green light will supply power to the blower much longer to satisfy the thermostat. When it's blinking, the thermostat is satisfied and the blower cycles.

 

[trx250r87]

I recall early on that some of the Heat Commanders shipped with incorrect damper motors or they were wired backwards or had their harnesses switched around. Make sure your firmware is up to date, motors are not lose and they cycle fully open and closed properly.

Eric

 

[Citationls]

I wouldnt worry about the single 12 inch duct. A single 12 inch round duct should flow slightly more cfm than six 6 inch ducts. If you look up duct cfm charts you can verify that for yourself. I believe elbows in larger ducts effect air flow more than elbows in smaller ducts so if you have lots of bends/elbows you might be moving a little less air than you would be with six 6 inch ducts with straight runs. Kind of nit picking at that point though given the application though.

Unless you had your entire hvac system redone, the technician had to match the duct size/cfm of the Heat Commander to the duct size of your existing system the best he/she could. Different duct sizes are used for different systems based on how much air the system is designed to move at a given static pressure.

Essentially, your hvac tech had to find a happy medium to adapt the HC duct work to the existing duct work which might explain the size of the duct he chose. Either that or I'm giving him/her way too much credit and they just did whatever made their life easiest 😂.

Wood furnace manufacturers dont tell you how complicated it is to properly design duct work. Luckily the systems are forgiving enough and we're only burning wood. Having not so efficient duct work doesn't matter much when the fuel is "free".

Also, if your damper door is just clicking (trying to close when its already closed) you can adjust the metal tab it presses up against to fix the issue. Im assuming you already went over that though if you were on the phone with sbi support already.

 

[fields_mj]

I wouldnt worry about the single 12 inch duct. A single 12 inch round duct should flow slightly more cfm than six 6 inch ducts. If you look up duct cfm charts you can verify that for yourself. I believe elbows in larger ducts effect air flow more than elbows in smaller ducts so if you have lots of bends/elbows you might be moving a little less air than you would be with six 6 inch ducts with straight runs. Kind of nit picking at that point though given the application though.

Unless you had your entire hvac system redone, the technician had to match the duct size/cfm of the Heat Commander to the duct size of your existing system the best he/she could. Different duct sizes are used for different systems based on how much air the system is designed to move at a given static pressure.

Essentially, your hvac tech had to find a happy medium to adapt the HC duct work to the existing duct work which might explain the size of the duct he chose. Either that or I'm giving him/her way too much credit and they just did whatever made their life easiest 😂.

Wood furnace manufacturers dont tell you how complicated it is to properly design duct work. Luckily the systems are forgiving enough and we're only burning wood. Having not so efficient duct work doesn't matter much when the fuel is "free".

Also, if your damper door is just clicking (trying to close when its already closed) you can adjust the metal tab it presses up against to fix the issue. Im assuming you already went over that though if you were on the phone with sbi support already.

Good point. My 12" duct does have one 90 deg elbow, and it only runs about 6' before tying into the main trunk line. Realistically, 12" is about all they had room for on the trunk line. The thing that surprised me was that he used a round duct instead of building a square or rectangular duct that had more area. He certainly charged enough to pay for that IMHO. If it works though, I'll call it water under the bridge and move on with life.

On the damper door, I'm seeing the limit switch register 0 ohms back at the board when the damper falls closed, so I know the tab/limit switch adjustment is correct, and yeah, I've already gone through that with tech support.