21 Hour Burn out of a Portage & Main 250

[J1m]

So, I loaded the P&M 250 last night at 7:00 p.m. pretty much full. There's space in front and in back of the logs, but I filled it pretty much to the top.

This morning at 8:00 a.m. I went out to check it and to my surprise it was still half full! Today was my day off, so I tried to see exactly how long I could go on one fill. I pushed everything to the middle to maximize the use of the secondary burn chamber...And then throughout the day I checked it...and checked it...and checked it again. I made it all the way to 4:00 p.m. on that one load of wood!

The average temperature from Weather Forecast & Reports - Long Range & Local | Wunderground : Weather Underground was 26.4* so it wasn't what you would consider a very cold night/day. But we're heating an 1880's 2,200 square foot farm house plus keeping a 24x30 shop @ 50*.

For those of you looking to install an OWB, P&M gets two thumbs up from me!

 

[karlk]

Wow thats a long time with one load! I never tried that ,but I always wanted to. Do you burn rounds or splits?

 

[J1m]

That's probably the most surprising thing, Karl. I'm burning splits that I cut and split in August. The wood is still fairly heavy and green - but it's doing the trick.

Yesterday while I was conducting my experiment, I finished cutting, splitting and stacking my 8 cord for 2013-2014. That's probably more significant than the 21 hour burn, but I forgot to take pics...So, didn't happen. :biggrin:

 

[Circle B MN]

Congratulations on your experiment.. I think if you refine your experiment a bit more you will get even better results. My CB5036 gets tended once a day, right after I get home from work, and always has wood left over. I fill only the front half of the box, usually with end cuts and junk wood from my firewood business. If we get in a real cold spell, sub zero multi day, I will use split rounds so they stack better in the box. I do believe the design and dry seasoned wood are due the credit. I would not own an OWB if I had to tend it more than once a day.

 

[owbguy]

Nice. Is that uncommon with that unit? I'm curious.

I have a Central Boiler 6048. Its a basic owb. My burn time exceeds 24 hours loading the front 75%-80% full with 28" wood. If I stuff it I can get 36 hours in cold Michigan weather, heating 2600 sq.ft main level, same size basement and 2 water heaters.

The owb idea is brilliant.

 

[Blazin]

:agree2: :msp_thumbup:

 

[J1m]

Nice. Is that uncommon with that unit? I'm curious.

I have a Central Boiler 6048. Its a basic owb. My burn time exceeds 24 hours loading the front 75%-80% full with 28" wood. If I stuff it I can get 36 hours in cold Michigan weather, heating 2600 sq.ft main level, same size basement and 2 water heaters.

The owb idea is brilliant.

36 hours is impressive indeed! I think we're comparing apples and oranges though. According to Central Boiler's website, your firebox is 60x48x36 or 60 cu ft. Almost a half cord of wood'll fit in your boiler! Compare that with my firebox which is 28x30x30 or 14 cu ft. That's about 1/4 the size! Using simple math, you should be getting 80 hour burns!

All joking aside, yes 21 hours is a really long time for my boiler/green wood combo. Sometimes (like last night when it was -8*) I struggle to get a full 12 hours. Hopefully as time goes by and my wood stockpile has ample time to dry my burn times will improve - but I thought 21 hours on less than 14 cubic feet of wood was pretty impressive.

 

[karlk]

Your right about the apple orange thing j1m I always get a kick out of car commercials that say they can go 500 miles on a tank of gas but dont say how big the tank is. I just finished my 2012-2013 wood also.

 

[MattNH]

Nice work Jim. I haven't tried that yet but may have to. I am still trying to fine tune the time of my burns so I have only a bed of coals when its time to refill.

Great minds must think alike. I was in the process of finishing up my wood for next season & beyond when my old maul handle broke (2nd time in the last 15 years). So, long story short, I just picked up a Fiskars x25 to speed things up. It should speed things up compared with my heavy old friend.

 

[owbguy]

36 hours is impressive indeed! I think we're comparing apples and oranges though. According to Central Boiler's website, your firebox is 60x48x36 or 60 cu ft. Almost a half cord of wood'll fit in your boiler! Compare that with my firebox which is 28x30x30 or 14 cu ft. That's about 1/4 the size! Using simple math, you should be getting 80 hour burns!

All joking aside, yes 21 hours is a really long time for my boiler/green wood combo. Sometimes (like last night when it was -8*) I struggle to get a full 12 hours. Hopefully as time goes by and my wood stockpile has ample time to dry my burn times will improve - but I thought 21 hours on less than 14 cubic feet of wood was pretty impressive.

ok. I was curious. That's why I asked.

I realize we are not comparing apples to apples. I can put in a lot more wood, but your boiler is way more efficient. Too bad we don't have the best of both worlds.

I only put wood in the front of my fire box and my logs are 32" and shorter, but mostly in the 24"-28" range. And I only load it about 24" high. So, its probably 28"x48"x24". When I stuff it, I mean I load the full height to where I cannot fit in any more due to the door opening.

 

[J1m]

Hey - someone check my math on the P&M firebox capacity. My math worked out to a little over 14 cu ft (14.375 to be exact) - but the P&M website says the firebox is 11 cu ft. Maybe they're taking the air tubes in to account or the rounded top? But this hardly looks like it would reduce the capacity by 3 cu ft.