MAxim 255 pe under performing

[Rsopha]

I have 5 maxims, 4 250s and one 255 pe. The 255 is giving me issues. ITs clean, as in you can eat off of it clean from the chimney to the back of the auger. it has 25 ft of insulated chimney on it, it sits in an insulated shed. It is heating a 550 gallon heat storage tank that my house, green house, and shop pull from. I took out a 250k btu coal boiler because I get seed corn for free. the coal boiler kept up easily and this thing took 5 days to get the water tank up to 140 degrees. the coal unit did 180 degrees in 24 hours. I am curious if this unit is over rated on btu output? I am also getting smoke in to the hopper. With that much draft on the chimney I didnt think I should have that problem. I am running the same fuel in the other 4 boilers with no issues in 4 years. any thoughts?
Thank you

 

[Mic]

I have 5 maxims, 4 250s and one 255 pe. The 255 is giving me issues. ITs clean, as in you can eat off of it clean from the chimney to the back of the auger. it has 25 ft of insulated chimney on it, it sits in an insulated shed. It is heating a 550 gallon heat storage tank that my house, green house, and shop pull from. I took out a 250k btu coal boiler because I get seed corn for free. the coal boiler kept up easily and this thing took 5 days to get the water tank up to 140 degrees. the coal unit did 180 degrees in 24 hours. I am curious if this unit is over rated on btu output? I am also getting smoke in to the hopper. With that much draft on the chimney I didnt think I should have that problem. I am running the same fuel in the other 4 boilers with no issues in 4 years. any thoughts?
Thank you

Good day and sorry to hear your issues. I have a 2020 255 and have issues as well. The boiler show temp of 190 degrees but only getting 155-160 to the home. Used the thermopex insulated 1 1/4 supply and return buried 24" down so no issues their and they claim only a 1 degree drop per 100 feet and Im 100 feet away. After 2 long winter of dealing with contractor and central boiler I got some answers that explain some temp concerns. I did the dealer change as to -10 degrees so if boiler shows 190 its actually 200 and seen the 10 degree gain immediately. Also changed the differential temps so boiler kicks into medium and high after 2 degree differential not the 10-20 degree that it comes from factory and this helps a bit. Hear is the bad issues - I noticed the temp sensor is around the mid/higher portion of the water jacket then I noticed the supply line was lower than the return line but contractor and central boiler said their is a pick up tube for the supply so its not coming off the bottom but this is incorrect, the supply line is actually at the bottom of the water jacket and the return line is about 5 inch above that so this would be very poor stratification and you would be getting the coldest water in the water jacket.....this is major and explains such as difference in what getting to the home. How does this boiler put out 165K but if its not supplying the temp? This seems to be a design flaw and costing customers frustration, money and time. Should I be wrong im certainly open to education too. I hope Central Boiler can do something about this such as installing a pick up tube so were taking off the top of water jacket or position the temp sensor near the supply line so if if show 190 on the boiler your getting 190 supplied to the building, not something 25-30++ degrees lower that what showing on boiler. Contractor and Central boiler have no solution or answers to correct this matter. We also took a thermometer and placed it in the water jacket and the temp difference of what boiler indicates is significant.
The oler 175 or 250 show 180 degrees and that's what you get coming out.....something was missed on the 255

 

[salecker]

Sounds like another happy CB customer...
Their reputation was so bad around here that a CB never was a consideration when i started my hydronics journey.

 

[BansheeTwin350]

I have 5 maxims, 4 250s and one 255 pe. The 255 is giving me issues. ITs clean, as in you can eat off of it clean from the chimney to the back of the auger. it has 25 ft of insulated chimney on it, it sits in an insulated shed. It is heating a 550 gallon heat storage tank that my house, green house, and shop pull from. I took out a 250k btu coal boiler because I get seed corn for free. the coal boiler kept up easily and this thing took 5 days to get the water tank up to 140 degrees. the coal unit did 180 degrees in 24 hours. I am curious if this unit is over rated on btu output? I am also getting smoke in to the hopper. With that much draft on the chimney I didnt think I should have that problem. I am running the same fuel in the other 4 boilers with no issues in 4 years. any thoughts?
Thank you

What's your fuel source? It sounds like 100% corn? Also what kind of burn chamber temperatures are you getting when running in medium and high? What are your fuel and air settings at for medium and high? Are you burning through fuel quickly? Is the fuel completely burn to ash by the time it falls off the burn chamber or is it will kinda whole?

A btu is raising 1lb of water 1 degree F. So you have 550gal * 8lb (per gallon) = 4,400. I'm assuming you're heating you tank from around 80 degrees to 140 degrees. So 4400 * 60 = 264,000 btu's needed to heat 550gal from 80 degrees to 140 degrees. So yes, massively underperforming and something is definitely not working correctly. That should only take ~2hrs. Which brings up additional questions. Is the boiler loop connected to the storage tank directly? Or are you using a heat exchanger to transfer heat to the storage tank?

I have a 255 pe and I do get the stated 190k btu/h that CB specs them at. So you should definitely be getting better performance from it. I've only seen smoke in the hopper when I start it up the first time of the season. I could be wrong, but it seemed that the burn chamber needed to get hot enough for the draft to work properly. Once it warmed up the smoke started going the correct direction.

 

[BansheeTwin350]

Good day and sorry to hear your issues. I have a 2020 255 and have issues as well. The boiler show temp of 190 degrees but only getting 155-160 to the home. Used the thermopex insulated 1 1/4 supply and return buried 24" down so no issues their and they claim only a 1 degree drop per 100 feet and Im 100 feet away. After 2 long winter of dealing with contractor and central boiler I got some answers that explain some temp concerns. I did the dealer change as to -10 degrees so if boiler shows 190 its actually 200 and seen the 10 degree gain immediately. Also changed the differential temps so boiler kicks into medium and high after 2 degree differential not the 10-20 degree that it comes from factory and this helps a bit. Hear is the bad issues - I noticed the temp sensor is around the mid/higher portion of the water jacket then I noticed the supply line was lower than the return line but contractor and central boiler said their is a pick up tube for the supply so its not coming off the bottom but this is incorrect, the supply line is actually at the bottom of the water jacket and the return line is about 5 inch above that so this would be very poor stratification and you would be getting the coldest water in the water jacket.....this is major and explains such as difference in what getting to the home. How does this boiler put out 165K but if its not supplying the temp? This seems to be a design flaw and costing customers frustration, money and time. Should I be wrong im certainly open to education too. I hope Central Boiler can do something about this such as installing a pick up tube so were taking off the top of water jacket or position the temp sensor near the supply line so if if show 190 on the boiler your getting 190 supplied to the building, not something 25-30++ degrees lower that what showing on boiler. Contractor and Central boiler have no solution or answers to correct this matter. We also took a thermometer and placed it in the water jacket and the temp difference of what boiler indicates is significant.
The oler 175 or 250 show 180 degrees and that's what you get coming out.....something was missed on the 255

I need to get some inline temp gauges installed. Currently I can only test the indoor pex with a laser temp gun. And I don't trust those guns because when I test different things with it, the readings seem flaky and inconsistent at best. But... If I test the temp of my indoor pex (after ~100ft of thermopex), I get a temp of 150 at the same time my maxim says 170. I've never trusted that it is actually a 20 degree temp drop as I'm not sure if I will get the same reading on the outside of pex as I would from the fluid inside and I don't trust my measuring device. But after reading your post I really want to get some temp gauges installed so that I can verify it.

 

[Mic]

I have 5 maxims, 4 250s and one 255 pe. The 255 is giving me issues. ITs clean, as in you can eat off of it clean from the chimney to the back of the auger. it has 25 ft of insulated chimney on it, it sits in an insulated shed. It is heating a 550 gallon heat storage tank that my house, green house, and shop pull from. I took out a 250k btu coal boiler because I get seed corn for free. the coal boiler kept up easily and this thing took 5 days to get the water tank up to 140 degrees. the coal unit did 180 degrees in 24 hours. I am curious if this unit is over rated on btu output? I am also getting smoke in to the hopper. With that much draft on the chimney I didnt think I should have that problem. I am running the same fuel in the other 4 boilers with no issues in 4 years. any thoughts?
Thank you

Good day. I have a 2020 M255PE and issues with big temp difference between boiler temp gage and actual water/glycol temp leaving supply line to home. Boiler Temp gage reads 190F and only getting 165 leaving the supply line. After 2+ years of trying to figure out the problem Central Boiler finally told me their is no pick up tube (their older m175 use to have) for the supply line so the supply line is on the bottom of the water jacket and return line is only about 2'' above that. Temp gage about midpoint on water jacket so of course it is hotter their then at the bottom. Painful and believe this is a design flaw, no help from central boiler. I cant see this unit even hitting its advertised and acclaimed 190000BTU out put. If central boiler can add a pick up tube or do something with the temp gage so your supply is same as water temp gage they could rectify the temp difference which is huge when your -25, -30, -40 C. Seems to go on def ears their though.

 

[Mic]

I have 5 maxims, 4 250s and one 255 pe. The 255 is giving me issues. ITs clean, as in you can eat off of it clean from the chimney to the back of the auger. it has 25 ft of insulated chimney on it, it sits in an insulated shed. It is heating a 550 gallon heat storage tank that my house, green house, and shop pull from. I took out a 250k btu coal boiler because I get seed corn for free. the coal boiler kept up easily and this thing took 5 days to get the water tank up to 140 degrees. the coal unit did 180 degrees in 24 hours. I am curious if this unit is over rated on btu output? I am also getting smoke in to the hopper. With that much draft on the chimney I didnt think I should have that problem. I am running the same fuel in the other 4 boilers with no issues in 4 years. any thoughts?
Thank you

With the supply line located on the bottom of the water jacket and their temp gage located mid point in water jacket their is a 20++C difference. Tested with cooking gage and it confirms water on bottom of water jacket is much lower temp then what the m255 gage reads. If more people speak up about this maybe central boiler will come up with a solution? I to did the dealer setting change as to -10C so when it shows 190 its actually at 200C but still doesn't get even 170C to home. I do have the thermoplex insulated 1 1/4'' lines and further insulation around it so the lines and flow are not an issue, its the design. Central boiler also said they have seen a slight increase in temp if one changes the return / supply lines around as return line is higher in water jacket than the supply line but they could not provide any information as to how much of a difference........so much for help.

 

[salecker]

CB help at it's finest
I am surprised that they can still sell stuff from all the customer support stories i heard before joining this site.
Then the stories from the rest of North America are on display here and other sites. CB doesn't care who speaks out obviously.
They just make stuff and sell it.