Cold Weather Test of Greenwood 100 in Fairbanks Alaska

[lancegillette]

I started using a Greenwood 100 about October 1, 2008 here in Fairbanks Alaska. It is located in a detached garage. It has a heat exchanger and I have 1.25" pex linking it to my Weil McClain oil boiler with a total loop length of about 180 feet.

Greenwood instructs you to operate the boiler at 165-180 Fahrenheit. We've had -30 to -41 weather for more than a week now. I was finding that I couldn't get the house temperature higher than about 66 or 67 F. So I adjusted the aquastat to burn from 180-190 F. and now I'm able to enjoy 72 temperatures in the house. I'm getting burn times of about 6.5 hours and using a combination of Aspen, spruce, birch, poplar--mostly Aspen/Poplar. When the weather is around 0 F. I easily get 8 hour burns or more. At this higher setting my Weil McClain is usually in the 160-170 degree range. When I run the Greenwood at the standard setting of 165-180 my Weil McClain is usually in the 150-160 degree range.

I don't have a heat storage tank, but it sounds like a good idea for warm weather operation (i.e. 15 F. or above).

 

[sdrobertson]

Sounds like you have the boiler pretty well figured out and I'm glad its working well for you. Were supposed to get the cold from your neck of the woods coming down next week starting on Tuesday. This sounds like you are having a good test of the system you have.

 

[Hydronics]

Fairbanks,
You refer to 0*F as warm, I refer to it as cold! Curious: what are you're typical outdoor temps.?
Unless you have uninsulated piping between the boilers & considerable heatloss, I'd bet one of the boiler temp. guages are inaccurate.

 

[lancegillette]

In January the temperature may never get above 0. Lows can be down to -55 in low areas. I'm at about 700 feet and our temperatures are a little milder. Last weekend we only got down to -41, but lower elevations were in the -50s. In winter we have temperature inversions so that the higher you get the warmer. Fortunately the colder it gets, the stiller the air. So wind chill is not a factor. When it is extremely cold, it often ends with a dramatic warming as breezy warm air moves into the region. The most extreme example is from about 20 years ago when it was -50 in the morning and by the end of the day it was 50 above. So it warmed up by 100 degrees in a single day. We prefer it to stay well below freezing so that the roads do not get icey. Schools never close because of cold weather, but a couple years ago they closed after the roads were glazed over after it rained in January and then froze. The roads were just too dangerous for the buses.

My pex between the boilers is insulated to R30, except for 20 feet where it runs inside the garage and helps keep the garage warm. I have two temperature guages on my oil boiler. I trust the digital readout from my Tekmar control more than the mechanical one that is on the boiler.

I frequently compare the temperature at the Greenwood after the heat exchanger with the digital readout at the oil boiler and they agree. So it looks like I lose little heat from the Greenwood to the to the Oil Boiler. I run the pex through an above ground utilidor and the snow on top shows no signs of melting whatsoever. So I don't think I have a problem with my gauges.

 

[lancegillette]

Last night the outdoor temperature had risen about 5-6 degrees to about -28 so I decided to change the aquastat from 180-190 F. to 175-185. The house temperature was maintained at 72 overnight and when I checked the boiler temperature after a 6.25 hour burn, the temperature was still in the 175-180 range and there was still significant fuel left for another hour of burning. I had put in more birch rounds in than usual, so the higher btu wood obviously is one factor in the longer burn. Warmer weather is forecast to arrive in about 3-4 days. We've now had 12 days now of cold weather (colder than -20). Back in 1917 they had 37 consecutive days of -20 or colder.

 

[henfruit]

i run mine in thehigh end also. i find it burns a lot cleaner and lasts longer. is this your first year with it? i have been burning all beech about 10 inch rounds, burns nice.

 

[lancegillette]

I started using mine about October 1 of last year. So what temperature do you like to run your's at? We don't have beech here. Birch is the best we have but I like to get my wood for free and you usually have to pay for birch. So I have lots of spruce, aspen, poplar. When you say it lasts longer, are you talking about the wood burning longer? Do you keep the 15 degree differential or do you make it narrower? I would think that having a narrower differential than 15 degrees would make for cleaner burns.

 

[ISeeDeadBTUs]

Cold in my corner of Upstate NY is single digits and below. Rare to go below -20 here, and when we do it's usually only one day/night.

When it gets cold, I set the aquastat to 190. Normally I run 180. During the summer I have run as low as 160.

Quality hardwood, load it and leave it, and momentum seem to be the keys to success with the GreenWood.

But I swear if I ever run into Barber's wife . . .

 

[henfruit]

i have mine set to close the damper at 195 to 200 i am not sure of the diff. i think it at 15d. big round seem to last a lot longer.but as you know how warm to do want to keep your house and how cold it is out and how large your house is ect. i owm 285 ac here so wood is not a problem to get just work. i have not tried any soft wood such as pine, but i have spoken to some one who does burn it. this is my 2nd year .last year was not good as i put it in side and had mostly split wood . i have it out side ina 10 x12 room with attached wood storage 12 x20. it is about 100 feet from the main house. on average i have to fill it every ten hours.it is nice and simple to use put in wood remove ashes thats it.

 

[henfruit]

leave barber alone he has a big title at green wood.ever read there board of director list reads like general motors.

 

[2.beans]

Last night the outdoor temperature had risen about 5-6 degrees to about -28 so I decided to change the aquastat from 180-190 F. to 175-185. The house temperature was maintained at 72 overnight and when I checked the boiler temperature after a 6.25 hour burn, the temperature was still in the 175-180 range and there was still significant fuel left for another hour of burning. I had put in more birch rounds in than usual, so the higher btu wood obviously is one factor in the longer burn. Warmer weather is forecast to arrive in about 3-4 days. We've now had 12 days now of cold weather (colder than -20). Back in 1917 they had 37 consecutive days of -20 or colder.

i run a seton which is the same thing ,kind of , with storage i run at 205 with a 10 degree diff.

 

[ISeeDeadBTUs]

leave barber alone he has a big title at green wood.ever read there board of director list reads like general motors.

So will wood-fired hydronics manufacturers be the next bail-out recipients?

I know Barber {thinks hes a big shot because he} has a fancy title, but he don't know Jack about customer service. Wives of highly paid executive types make for the best scratch . . . they've been under appreciated so long, plus they like to spend the man's money :lol:

 

[lancegillette]

Last night it was -30 again. I set my thermostats to 70 instead of 72. I loaded it with my regular mixed load of wood types--not much birch this time. I got 8 hours sleep before I heard my oil boiler come on signalling to me the Greenwood was low on fuel. I'm still running the Greenwood at 175-185. First time this week I got a good 8 hours sleep.

 

[henfruit]

good to hear you got some sleep. i think you are getting a handle on things.

 

[lancegillette]

Got another 8 hours sleep again as I set the thermostat to 69. Wood was still burning when I checked on the boiler. I set the Greenwood temp back up to 180-190 to help speed up heating the house back to 72. It takes hours for the house to get back up to 72 from 69 in this weather. Looks like by Tuesday (in three days) weather will be near zero again.

 

[Steaming Pile]

Fairbanks, Just wondering if you have the heat retention kit on your GW? If not it may help you get through the night. I'm not using one but plan to upgrade when I have a couple extra bucks laying around.

 

[djblech]

The temps here have been below 0 and are supposed to continue even colder this week. I slept in this am, got 8hrs, water temp down to 120. I have my aquastat set at 185 with a 15 degree differential. Below 0 degrees I am only getting about 6.5-7 hrs burn. I have the heat retention kit, if aquastat is set at 175 my water temp has dropped below 140 and then the unit shuts down to save heat. I seem to have better luck with aquastat set at 182.5. Are you using a draft assist? Do you get alot of smoke when you open the door and or are stoking fire. My garage smells really smokey, Its hard to load the firebox without lots of smoke.

djblech
Bruno MN (20 miles s of Duluth)
greenwood 100 no storage

 

[henfruit]

i would raise your aquastat up 195. what do you mean by draft assist?how full are you filling the fire box when you losd it for the night.

 

[Steaming Pile]

[quote author="djblech" date="1231730261"]The temps here have been below 0 and are supposed to continue even colder this week. I slept in this am, got 8hrs, water temp down to 120. I have my aquastat set at 185 with a 15 degree differential. Below 0 degrees I am only getting about 6.5-7 hrs burn. I have the heat retention kit, if aquastat is set at 175 my water temp has dropped below 140 and then the unit shuts down to save heat. I seem to have better luck with aquastat set at 182.5. Are you using a draft assist? Do you get alot of smoke when you open the door and or are stoking fire. My garage smells really smokey, Its hard to load the firebox without lots of smoke.

I have a tjurnland auto draft. It helps but does not eliminate smoke while loading. Stage your wood in front of the load door , load it fast and slam the door shut. Don't open again until it's time to reload. Works well for me. Don't really slam the door :lol:

 

[djblech]

henfruit,
Greenwood sent a picture of a draft assist, it looks like a squirrel cage blower that mounts right on the stove pipe. It is meant to be turned on before you open the door. I don"t jamb the firebox full, but it is about 1/2 up the door. If I turn the stat up won't it burn wood faster?
djblech
greenwood 100

 

[henfruit]

i have a draft inducer but dont use it much it works ok but my boiler is an out building so a little smoke is ok. i load at 800pm 4 to 5 good size rounds about the same up the door. hotter may burn faster but you are getting more heat from from the system i think. 8 to 10 hours with your temps seems to be what you are going get ? i got 10 hours last night.