Probably a fluke, mine have been rock solid but a back up is a good idea. Course we're all buying these off EBay, with an unknown history, some of these could be factory rejects, returns or what have you, who knows?
Everything Drolet Tundra - Heatmax...
- Thread starter brenndatomu
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Probably a fluke, mine have been rock solid but a back up is a good idea. Course we're all buying these off EBay, with an unknown history, some of these could be factory rejects, returns or what have you, who knows?
If you get a new one, it will be interesting to see if it makes the same sounds from the motor...every motor and each individual blower/furnace seem to sound different, I wonder if the individual ICM has anything to do with it? Hmmm...
sloeffle
Minister of Fire
During this last cold snap I was actually able to raise the house temp 3 or 4 degrees in a few hours. Once the house got up to 72 or so I didn't fill the furnace again until the house got down to about 70 or so. In normal temps I generally only have to put about 6 medium size splits in the furnace to get the house temp up 3 or 4 degrees.
Like a lot of newer built houses, if the wind isn't blowing bad, my house isn't hard to heat. When the wind is blowing bad, that is a different story.
sloeffle
Minister of Fire
I bought the last one from flebay. I'm pretty sure it was NOS or return stock. It was the new design though. I was looking at it last night trying to figure out a build date but none of the stickers really have anything meaningful. If anybody knows how I can decipher the information on the stickers I'd like to know. I could take some pics of the stickers and maybe we can figure it out.
JRHAWK9
Minister of Fire
shut your face, don't want to hear about you guys and your efficient homes and how easy they are to heat in frigid temps. 
Although, I will say, I was pleasantly surprised to wake up this morning to -16° temps outside and 72° in the house. The Kuuma's going to be getting a workout for the next week to keep our place warm.....
Mrpelletburner
Minister of Fire
Looking for some photos of how folks connected the Tundra II air ducts. I don’t have a central air system setup, just 2 8” trunks supplying floor vents. Trying to figure out if I am going to have to replace the 8” duct trunk for the duct that will connect to the Tundra.
Basically has anyone gone from 2 8” ducts to several branches? If so, can you provide some photos of the setup?
Basically has anyone gone from 2 8” ducts to several branches? If so, can you provide some photos of the setup?
Tundra ll has 10 6inch plenum take offs. It no longer has the 2 8 inch that was previously on the tundra 1.
Mrpelletburner
Minister of Fire
Yes... My setup currently has 2 8” runs. So I am guessing I would have to re-duct my system. Need to add in that cost with the stove.
You are going to need to add at least one 8" run somewhere...IIRC they call for at least (6) of the (10) available 6" duct connections to be used...that's ~170 sq inches of area in total...(2) 8" runs only gives you ~100 sq in...(3) of them gets you in the 150 sq in area...that would be my absolute minimum...(4) 8" runs would be better.
I would buy a sheet metal circle cutter and cut 8" holes into the plenum as needed to make the simplest 8" connections.
https://www.menards.com/main/heatin...und-hole-cutter/thht-1448/p-1488180037069.htm
https://www.menards.com/main/heatin...3-c-14260.htm?tid=-4911635956121324284&ipos=7
I would buy a sheet metal circle cutter and cut 8" holes into the plenum as needed to make the simplest 8" connections.
https://www.menards.com/main/heatin...und-hole-cutter/thht-1448/p-1488180037069.htm
https://www.menards.com/main/heatin...3-c-14260.htm?tid=-4911635956121324284&ipos=7
sloeffle
Minister of Fire
Well, all good things must starts somewhere. Ran the furnace for a few days without the speed controller. I must say it is night and day with and without it. IMHO it makes the furnace heat a lot better. The polar vortex is coming in a few days and I didn't want to listen to the furnace turn off and on all night so I went to a local HVAC supply house and picked up a Totaline P251-0083h today. Called another place and they wanted way too much money for a ICM 326. Got it hooked up and man does she purr like a kitten. I have the Totaline set to the middle settings on the cut out speed and the motor doesn't make the weird sounds it was making with my previous 326. I did have to wire 24V into it, but that wasn't a big deal.
I did figure something interesting out today too. It looks like (broken link removed to https://www.ferguson.com/product/mitsubishi-electronics-usa-105-degree-f-line-volt-head-pressure-control-micm326hm2/_/R-4111930)uses ICM 326 units to modulate the fan on their mini splits. I do find the temperature swing on their unit interesting too.
Thanks to @JRHAWK9 for posting a wiring diagram back in 2017 that actually made sense, and @brenndatomu for answering all of my questions.
I did figure something interesting out today too. It looks like (broken link removed to https://www.ferguson.com/product/mitsubishi-electronics-usa-105-degree-f-line-volt-head-pressure-control-micm326hm2/_/R-4111930)uses ICM 326 units to modulate the fan on their mini splits. I do find the temperature swing on their unit interesting too.
Thanks to @JRHAWK9 for posting a wiring diagram back in 2017 that actually made sense, and @brenndatomu for answering all of my questions.
JRHAWK9
Minister of Fire
This is the exact unit I have, well, have two of.
Glad my grade school sketch helped someone.
sloeffle
Minister of Fire
Your grade school sketch makes more sense to a person that doesn't work on electric everyday than what is in the book. I know what hot and neutral and ground are. Load and line don't click in my brain since I'm not around it everyday. I'm sure if you were a HVAC tech or an electrician, load and line make sense.Glad my grade school sketch helped someone.
Line is the power source, load is what is being powered...but even with doing electrical work pretty regularly, I find ICM's drawings to be confusing.
Mojappa
Burning Hunk
I know there was a few consecutive posts of people showing off their finishing nails, can’t seem to find it now. I’ve got an endless supply of metal hangars and was wondering if they would be too thick to use in place of the finishing nail. Ultimately if it’s too big I’ll just blow through the load faster and can work down from there,just looking for some insight before I fire this bastard up again this evening. Last burn (first for the stove) went ok but i think I have a bit too weak of a draft to let the flap fully close, ended up with some chunks just smoldering for hours and dumping that smell into the house. Hoping a nail/hangar piece will provide a more complete burn
Never had a nail stick or get jammed doing it this way.
I used a side grinder to do the fine tuning.
I made one for cold weather and another for warm.
Attachments
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Nothing like waiting until the coldest day of the year so far to install my Totaline P251-0083H controller!! Haha!
I started the install last night, but the thermistor I used was not the correct one. I used a Totaline P251-0086 thermistor, and with HOT to touch plenums, the blower was running VERY slowly. I looked it up online, and the P251-0086 has the following temp vs resistance:
![[Hearth.com] Everything Drolet Tundra - Heatmax...](https://www.hearth.com/talk/attachments/p251-0086-webp.239679/ "[Hearth.com] Everything Drolet Tundra - Heatmax...")
The thermistor that is included with the Totaline controller has a considerably lower range.
![[Hearth.com] Everything Drolet Tundra - Heatmax...](https://www.hearth.com/talk/attachments/p251-0083h-webp.239682/ "[Hearth.com] Everything Drolet Tundra - Heatmax...")
So, the Totaline controller wants to see a resistance of ~6.6kΩ to run at 100%, and 11.8kΩ at 0%, and with the 0086 thermistor, with hot plenum temps I was still likely only around 9.5-10Ω and therefore only running the fan at 10-20%.
I put it back to factory wiring last night once I realized I needed to change my thermistor or add a resistor to the 0083H thermistor.
Today I used the factory included thermistor and a 2.94kΩ resistor (couldn't find a 5KΩ pot at work) in series. I considered other resistances, but the 2.94kΩ in series seemed to be the best starting point. I wired my blower on Speed 3, instead of Speed 1 which I had been on. I'm sure my static pressure is pretty high, but especially this time of year, loading the furnace up to the max, I might as well run a higher CFM... Time will tell.
Here's what I calculate to be the blower speeds based on temp.. My adjustable snap disc should shut the blower off around 100°F (and 50% speed) if I recall correctly.
![[Hearth.com] Everything Drolet Tundra - Heatmax...](https://www.hearth.com/talk/attachments/seriesresistance-webp.239683/ "[Hearth.com] Everything Drolet Tundra - Heatmax...")
I will order and switch to a probe type thermistor, like @3fordasho used.
I started the install last night, but the thermistor I used was not the correct one. I used a Totaline P251-0086 thermistor, and with HOT to touch plenums, the blower was running VERY slowly. I looked it up online, and the P251-0086 has the following temp vs resistance:
The thermistor that is included with the Totaline controller has a considerably lower range.
So, the Totaline controller wants to see a resistance of ~6.6kΩ to run at 100%, and 11.8kΩ at 0%, and with the 0086 thermistor, with hot plenum temps I was still likely only around 9.5-10Ω and therefore only running the fan at 10-20%.
I put it back to factory wiring last night once I realized I needed to change my thermistor or add a resistor to the 0083H thermistor.
Today I used the factory included thermistor and a 2.94kΩ resistor (couldn't find a 5KΩ pot at work) in series. I considered other resistances, but the 2.94kΩ in series seemed to be the best starting point. I wired my blower on Speed 3, instead of Speed 1 which I had been on. I'm sure my static pressure is pretty high, but especially this time of year, loading the furnace up to the max, I might as well run a higher CFM... Time will tell.
Here's what I calculate to be the blower speeds based on temp.. My adjustable snap disc should shut the blower off around 100°F (and 50% speed) if I recall correctly.
I will order and switch to a probe type thermistor, like @3fordasho used.
Dave, I'm not sure how the Totaline P251-0086 thermistor worked for you, is there a chance that that was a typo or a bad cross reference? Maybe the ICM controller is looking for a different resistance range. That's all I can think of, but I don't see any way it would work right with my Totaline controller.
sloeffle
Minister of Fire
I'm using the thermistor from my 326 with my new Totaline P251-0086 and it works good IMHO. From a visual reference they both look identical so that is why I didn't change out the one from the 326. It is possible though that they are set to measure different temps though.
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I'm happy with the probe type I detailed in a earlier post, or maybe the sticky thread. It's working well on two different furnace installs. Don't just hang the probe in the air flow above the heat exchanger - I put mine in a aluminum block screwed to the sheet metal right above the front center outlet that I didn't use to connect a duct run. The block tempers the temp changes and results in less swings in fan speed. Oh and get the 5k pot, it allows you to set the speed right where you want it with the twist of a knob. As far as the motor tap, I use a higher speed tap on the house unit with lots of duct work and long runs, and a lower speed in the shop with almost no duct work and much lower return air temps because shop temps are lower.
trx250r87
Burning Hunk
Hmm, I'm not sure. I wonder if something didn't cross reference right, or it was a typo. The P251-0085 from Totaline looks to be much closer in resistance to the original one.
Thanks, I have searched your posts to see that. I may try to check the temp/res curve on the probe like yours, and the aluminum block is a great idea to help steady the temp swings - like when the damper opens and closes frequently.. I definitely will still get a 5k pot, but wanted to get the blower mod running today.
Possibly my dad. Details? I can't see the facebook picture.
trx250r87
Burning Hunk
I don't know any more that what the post says. Looks a little dirty!
Eric
![[Hearth.com] Everything Drolet Tundra - Heatmax...](https://www.hearth.com/talk/attachments/cc0b66c2e42abd3666cd9948ec811d06-webp.239690/ "[Hearth.com] Everything Drolet Tundra - Heatmax...")
Eric
trx250r87
Burning Hunk
I found the ad and saw more pictures as well. Looks neglected. I'd buy it but not for anywhere near his asking price,
That's actually a T1 I do believe. A T2 would have a plenum.
Yeah, could've been...been a while now, I'd have to go back and look things up.
I ended up using the standard temp sensor that came with the controller. Just added a 1.2k resistor...worked perfect. Also, the aluminum block for the sensor is a real good idea...I kinda did the same thing by taping the sensor to the outside of the ductpipe right above the furnace...used that high temp aluminum tape. Then taped a bunch of high temp insulation over top of that area too. Had much the same effect as mounting to a block would.
On my current setup I also used a standard sensor, but with a 5k pot, and that is definitely the way to go, its so easy to change the target operating range if you want.
