My Central Boiler Maxim M255 PE journey

[thenrich]

After 13 years of owning a Central Boiler Classic 6048 we finally traded it in for the Maxim pellet/corn boiler. The 6048 did a great job of heating our 3200 sq/ft in north-central Wisconsin and has certainly paid for itself a few times over. The nice thing about those things is they burn anything and everything. Zero problems mechanically but she was a hungry beast and I was always chasing down firewood (12 - 15 full cords annually). For pellets or corn someone just delivers them and places pallets neatly in any location you'd like in about 30 min vs. weeks and weeks of harvesting, splitting and stacking. Easily worth the extra expense of pellets. Because we liked the idea of alternative fuels we decided on the pellet boiler. Our indoor gas furnace has always been our backup.

With all that stated I noted there really isn't much online about these things so I thought I start a journal of sorts. Here are some facts to add context to the journal as I make logs

1. The first big obvious difference is the size of the M255 is less then 1/2 the size of the 6048 and only holds 90 gal of water.
2. The boiler sits next to our exterior garage about 90ft away.
3. Our house was built in 2006 and is modern construction. It is 2x6 construction and very well insulated. We have 3 levels.
4. We heat the entire house, domestic water and a 28x28 external 2x6 construction insulated garage.
5. I'm starting out with 8.4 ton of softwood pellets. I really don't know where we'll end up but that's all the extra room I had in my detached garage.

After the initial installation we started it right up with no issue. It's electric ignition. I have not alternated the standard air settings that were pre-set from the factory. I feel like that will be a learning process. I will keep the post undated with bags of fuel used, temps, problems, etc

 

[JRemington]

Did they recommend thermal storage?

 

[Mr._Graybeard]

I've heated our old southern Wisconsin farmhouse with a Harman PB 105 pellet boiler for seven seasons. We have a hydronic heating system, so the boiler is my choice; if I had a forced air system I would have opted for a furnace like a Harman PF 100 or Fahrenheit Endurance. My boiler is in the basement and direct-vented. It radiates heat that I would have wasted if I had an outdoor boiler. My system transfers heat to my backup cast-iron oil boiler, but since the burn is 100% controlled, I have never seen a need for any kind of storage.

Last winter we burned about 5 tons of pellets. We're usually in the 5-6 ton range. The house is 100-plus years old and poorly insulated in spots.

 

[Former Farmer]

Did they recommend thermal storage?

I think that with a pellet boiler, storage is not a concern. The boiler can modulate to whatever feed rate is required for the set temperature. With a firewood boiler, I think the storage was to be able to burn the wood efficiently and store the extra heat generated. I don't know if a pellet boiler running at 50% capacity is that much less efficient than running at 100%.

I know that talking with "Sting" on the old Iburncorn forum, he highly recommended leaving the energy in the pellets rather than losing some energy in storage.

 

[thenrich]

Did they recommend thermal storage?

No, the water jacket is insulated and meant to be outside. With this weekends snow I noted the show did not melt on top of the boiler.

 

[thenrich]

I seem to be going through 1.25 - 1.5 bags a day. Temp has been between 25 - 45 degrees. Very little ash or smoke. It smokes a little between cycles.

I also found Superior pellets at Fleet Farm for $3.99 I mixed the fuel in the hopper 1:1 and really haven't noticed a difference yet. Superior is a hardwood and is a darker pellet.

 

[Mr._Graybeard]

I'm probably burning a bag a day at this point with temps in the 30s-40s. I burn Superior/ Marth pellets all the time, in fact I just picked up a ton for $199.50 at Fleet Farm. I do prefer Menards because they keep the pellets under cover.

 

[thenrich]

I'm probably burning a bag a day at this point with temps in the 30s-40s. I burn Superior/ Marth pellets all the time, in fact I just picked up a ton for $199.50 at Fleet Farm. I do prefer Menards because they keep the pellets under cover.

haha....I actually just did the same at Menards and I'll just mix as I go.

I did try some Marth as it was a local gas station. I think it was like $5.50 a bag? Really dark pellets.

 

[thenrich]

I've heated our old southern Wisconsin farmhouse with a Harman PB 105 pellet boiler for seven seasons. We have a hydronic heating system, so the boiler is my choice; if I had a forced air system I would have opted for a furnace like a Harman PF 100 or Fahrenheit Endurance. My boiler is in the basement and direct-vented. It radiates heat that I would have wasted if I had an outdoor boiler. My system transfers heat to my backup cast-iron oil boiler, but since the burn is 100% controlled, I have never seen a need for any kind of storage.

Last winter we burned about 5 tons of pellets. We're usually in the 5-6 ton range. The house is 100-plus years old and poorly insulated in spots.

We have hydronic in our finished basement, forced-air everywhere else.

 

[Mr._Graybeard]

haha....I actually just did the same at Menards and I'll just mix as I go.

I did try some Marth as it was a local gas station. I think it was like $5.50 a bag? Really dark pellets.

Superior is a Marth brand. I think the pellets are all pretty much the same, at least the hardwoods are. They have also sold hardwood pellets under the Pennywise brand -- I used to see them all the time at Menards.

I wonder if you see Rib Mountain pellets in your area. They have had a great reputation, but limited distribution. They also were in some financial trouble awhile back and may no longer be in business. I don't see much recent mention of them online.

Otherwise, I like Dejno's pellets, which come as either softwoods or a hardwood/softwood blend. The blends are usually pretty competitive with hardwood brands price-wise. Indeck was big into pellet production up in Ladysmith, Wis., but I haven't seen them in the big-box stores in quite some time.

If you have a Tractor Supply in your area, they sell Ozark Hardwood pellets under a house brand. I don't recommend them -- If you think Marth pellets are dark, you should see Ozarks. They burn OK but don't produce a lot of heat. They also are very ashy.

 

[thenrich]

Just a brief update: I'm getting about 7 days right out of about 400lbs (10 bags) mixed Superior (Hardwood) and Western Elite (Softwood)

I really dunno if that's good or bad but I'm sure demand will increase as it turns colder. Next week is high in the 30's and I'll be bow hunting the next 2 weeks so I should be able to keep tabs on usage.

 

[Mr._Graybeard]

I found a copy of the owner's manual for your heater. It looks like a bottom-feed design. It should be able to handle hardwood pellets without any worries about ash buildup -- in fact, you might want to consider blending hardwoods and corn instead of the softwoods.

 

[thenrich]

I found a copy of the owner's manual for your heater. It looks like a bottom-feed design. It should be able to handle hardwood pellets without any worries about ash buildup -- in fact, you might want to consider blending hardwoods and corn instead of the softwoods.

Corn is so expensive compared to pellets right now. I might dump a bag in there just to see what happens though.

 

[thenrich]

Update: Been using the boiler for over a month now. In the house and domestic water really no difference then the 6048. Few items to mention:

1. It appears I have a leak somewhere as every day when I look under the chimney box in the back of the unit I see a small puddle of water. At first I thought it was nothing, maybe condensation. After further inspection though I've noticed I've been having to add additional water to the reservoir. I do it right from the house and takes less then a minute. Although, not hard to do, I called the dealer for an appointment. They are coming Friday. I also called CB and was able to talk to a very knowledgeable employee. He suspected back-burns in which the boiler extinguishes the burn with water from the reservoir vs something really bad like the water-jacket. So I'll update this post when I learn more. (update - 12/3/2019: It turned out there was no leak. The system just was not entirely full of water and took time through multiple cycles of pumping water through the in-floor heating)
2. It appears Marth's brand Superior hardwood pellets suck. I normally burn the Western Elite Ponderosa Pine but have been experimenting with the cheaper Marth Pellets. To my surprise they really burn like crap. I'm left with a big pile of pellets not completely burned. They seem to be ok if I mix, and mix really will, with the softwood pellets. The softwood pellets leave a nice little pile of ash and that's it. (update - 12/3/2019: The Superior pellets indeed DO NOT suck. I had my fuel rate set too high and the air rate too low. They are good pellets and burn very well with little ash.)
3. It's getting cold here, highs in the teens and lows in the single digits. I really haven't messed with the stock airflow settings higher or lower yet and I haven't seen where the unit struggles a lot to keep up. The only time we really saw it kick into high was on the initial startup and it was bringing the in-floor heating up to temperature.
4. To date, the big buck I've been bow hunting has eluded me. With that said my 12 y/o got his first with a compound by himself in a stand this season. I dunno why I posted that but it's a major part of my fall life (update - 12/3/2019: I am still chasing him into late season.)

 

[thenrich]

In regards to the Superior wood pellets I adjusted to the medium air adjust a bit higher and now everything burns to a fine powder. On the Maxim when you adjust the air higher the feed rate is also increased. So I'l see how that effects consumption with it burning a bit hotter.

As a side note: With the last couple of days with mornings below zero I did notice the unit kicking into high-fan mode (there are 3 on the maxim - high/medium/low. Each with their own individual air adjust). This happens when water temp drops below 20 degrees above set water temp. For this to happen it needs to be really cold and the in-floor heating in calling for demand. In high-mode even at medium setting it's like a blast furnace in there.

 

[thenrich]

Brief update: All of winter is here with cold and snow. No issues to report. I did however stumble on a pretty good mix of fuel. I use 1 bag hardwood, i bag softwood and 1 bag corn. This seems to bring the best bang for the buck - burns really good. Kinda weird looking in the firebox and seeing clumps of pellets attached to a kernel of corn. Its like the kernel melts and the pellets stick too it. They remind me of little burning stars. After awhile the agitator breaks the clumps down it dust.

I've found the best setting for this mix is to adjust the air a bit higher then the feed rate. Super happy with everything so far. I know I can go a few days without doing anything to it but I still check it daily. I usually level off the bin with fuel. I also remove any ash at the end f the firebox agitator.

 

[thenrich]

Just checking in with an update. Still super happy with everything. If I had to make a guess on fuel total I'd guess between 11-12 tons. Thats a mix of softwood, hardwood and corn. So much nicer then the wood boiler.

I usually check it once a day and top it off but could easily go a few days without putting fuel in the hopper. I also take 10-15 min each week to clean as well.

 

[terramedi]

Just checking in with an update. Still super happy with everything. If I had to make a guess on fuel total I'd guess between 11-12 tons. Thats a mix of softwood, hardwood and corn. So much nicer then the wood boiler.

I usually check it once a day and top it off but could easily go a few days without putting fuel in the hopper. I also take 10-15 min each week to clean as well.

Nice! I go through around 14 ton of pellets per year.

 

[GreenDave]

Hi. My Father-In-Law just purchased and installed a new Maxim M255PE wanting to burn corn. The furnace does not heat the water up enough to generate any heat. He has tried using wood pellets as well as corn and the water temperature always ends up going back down to around 100 to 120 degrees. The auger does not seem to put out enough pellets. The fire itself is only at the one end of the auger. The dealer is not helping. Keeps saying it's our corn or pellets are no good. We have the code to change factory settings, but if we increase the auger time, then the pause time between the auger running seems to also increase. You can hold the auger button manually every so often and get the temperature goes up to around 150 easy, so we're thinking has to be something with the settings? Would like to burn 1/2 corn and 1/2 pellets. I keep thinking, has to be something wrong if fire is only at the very end of auger where pellets come in? The auger just doesn't seem to turn long enough, soon enough. Any help would be more than appreciated. This furnace so far is completely useless. Father in Law has a different corn stove in the house and the corn burns excellent in it, so the dealer blaming the fuel is crazy. I'm going there soon to check the settings on HIGH mode, I think feed rate and air are set to the highest.

 

[thenrich]

Hi. My Father-In-Law just purchased and installed a new Maxim M255PE wanting to burn corn. The furnace does not heat the water up enough to generate any heat. He has tried using wood pellets as well as corn and the water temperature always ends up going back down to around 100 to 120 degrees. The auger does not seem to put out enough pellets. The fire itself is only at the one end of the auger. The dealer is not helping. Keeps saying it's our corn or pellets are no good. We have the code to change factory settings, but if we increase the auger time, then the pause time between the auger running seems to also increase. You can hold the auger button manually every so often and get the temperature goes up to around 150 easy, so we're thinking has to be something with the settings? Would like to burn 1/2 corn and 1/2 pellets. I keep thinking, has to be something wrong if fire is only at the very end of auger where pellets come in? The auger just doesn't seem to turn long enough, soon enough. Any help would be more than appreciated. This furnace so far is completely useless. Father in Law has a different corn stove in the house and the corn burns excellent in it, so the dealer blaming the fuel is crazy. I'm going there soon to check the settings on HIGH mode, I think feed rate and air are set to the highest.

Welcome, you've come to the right spot.

First off I'd say I actually struggled with a similar issue and called CB directly and and talked to a very knowledge person on the adjustments of the Fire Star control panel. I'm not certain which code your referring to? The dealer code maybe? Either way you don't wanna mess with that. I think messing with anything outside of the factory specs using the dealer code would be bad and would indeed lead to poor results. Go back to factory if possible.

Here are instructions for adjusting air and feed-rate independently - which is all you should need:

1. To modify the feed rate simply press the up/down arrows in High or Medium (I never touch Low).
2. To modify the air-flow hold down the 'Air Adjust' button while pressing the same up/down arrows.
3. Note: The unit will kick into high once the water temp drops below 20 degrees from the pre-set (I set my water temp at 180). Mine seems to go in High mode when it's below zero and my in-floor heating has demand. In high mode It'll be like a blast furnace.
4. Note: For my situation and demand, I have both my medium and high modes, for both air and feed rates, set one notch above medium in the led. Really once notch above factory setting.

Based on what your saying in your post you need to adjust the feed rate (item #1 above) to accommodate the volume of air coming into the burn chamber. Sounds like you have plenty of air and not enough fuel.

I would also suspect you should be seeing a bunch of water/ice from condensation at the bottom of your chimney stack due to insufficient heat. That will go away once you adjust the unit.

A combination of corn and pellets should burn very well.

I hope this helps.
-Tom

 

[GreenDave]

Welcome, you've come to the right spot.

First off I'd say I actually struggled with a similar issue and called CB directly and and talked to a very knowledge person on the adjustments of the Fire Star control panel. I'm not certain which code your referring to? The dealer code maybe? Either way you don't wanna mess with that. I think messing with anything outside of the factory specs using the dealer code would be bad and would indeed lead to poor results. Go back to factory if possible.

A combination of corn and pellets should burn very well.

I hope this helps.
-Tom

Thanks Tom. I went to my In-law's house last night and I think we have it figured out better. The furnace now runs around 150 degrees heating the shop and house. We think the issue was a jam between the two augers. We now know to watch the flow of material through the little window at the back of furnace. Before you could not see any "space" or air gaps, corn looked solid in the window. Now you can see some space between the corn and pellets, and everything is flowing better. The High air setting is around half. We have the feed rate cranked to one notch shy of the highest led. We mixed in more wood pellets in the corn / wood pellet mix also.

- Dave

 

[thenrich]

Thanks Tom. I went to my In-law's house last night and I think we have it figured out better. The furnace now runs around 150 degrees heating the shop and house. We think the issue was a jam between the two augers. We now know to watch the flow of material through the little window at the back of furnace. Before you could not see any "space" or air gaps, corn looked solid in the window. Now you can see some space between the corn and pellets, and everything is flowing better. The High air setting is around half. We have the feed rate cranked to one notch shy of the highest led. We mixed in more wood pellets in the corn / wood pellet mix also.

- Dave

I'm glad you have things figured out. According to that pic above the feed rate is one notch above medium - you still have a lot more adjustment? The only way to see the air is to press the 'air-flow' button. Do you recall what water temp your in-laws set the water temp at? 150 is really low. If I recall recommended is around 175.

 

[thenrich]

Update: Pellet boiler running fine. Going away for a weekend and not having to worry about the fire going out is very nice.

I'm really just getting sick of winter though :-(

 

[Mic]

Thanks Tom. I went to my In-law's house last night and I think we have it figured out better. The furnace now runs around 150 degrees heating the shop and house. We think the issue was a jam between the two augers. We now know to watch the flow of material through the little window at the back of furnace. Before you could not see any "space" or air gaps, corn looked solid in the window. Now you can see some space between the corn and pellets, and everything is flowing better. The High air setting is around half. We have the feed rate cranked to one notch shy of the highest led. We mixed in more wood pellets in the corn / wood pellet mix also.

- Dave

Good day. FYI - The maxim M255PE has supply line on bottom of water jacket and return line is only 2'' or so above the supply. Hardly if any time for stratification. Temp gage on M255PE indicated 190 but only 168 coming from the supply line on bottom of water jacket. I been dealing with CB for past 2 inters now as they just let me know their is no pick up tube for supply line which is why water leaving supply is 20 degrees below gage