Outdoor Wood Furnace Info

All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: Scott7m on March 23, 2013, 11:42:35 AM

Title: More about operating temps
Post by: Scott7m on March 23, 2013, 11:42:35 AM
Natures Comfort just added a new part to there warranty, which shows they to are seeing the importance of keeping firebox temps up.  They likely haven't gotten to the part of return temps being as important, but I suspect they'll be looking at some type of thermostatic valve soon as well

This is from the mew warranty.

The Nature's Comfort 20 Year Limited Warranty

Nature's Comfort LLC, of Shipshewana, IN 46565 warrants material and labor on any defects in workmanship on the fire drum for a period of 20 years from the purchase date to the original owner only (see proration below). The water jacket is warranted for a period of 10 years from the purchase date to the original owner only (see proration below). If there is a leak in your properly delivered, installed and maintained Nature's Comfort boiler, we will cover repair costs for the first 5 years and prorated after that (see below).  Repair can be denied if the unit's water jacket has exceeded 220 degrees. The aquastat must be set so the water jacket temperature never falls below 150F otherwise condensation will be created on the inside of the firebox and will cause corrosion that is not covered under warranty.
Title: Re: More about operating temps
Post by: WoodMOJoe on March 23, 2013, 02:46:40 PM
Interesting.  Is there a positive way of knowing...or proving what temps an aquastat has been set to?
Title: Re: More about operating temps
Post by: Scott7m on March 23, 2013, 07:09:35 PM
Nope.... 

I also wanna see someone get a stove 220 degrees, water won't get that hot unless its under pressure. 

The thing is though how would anyone know where they had kept the aquastat set at?  Loopholes loopholes

That's why I say it's important to have a good install and hopefully a dealer that has some leverage if a problem should arise
Title: Re: More about operating temps
Post by: yoderheating on March 23, 2013, 07:51:48 PM
I guess the furnace could easily hit 220 if you ran it without water in it?
Title: Re: More about operating temps
Post by: Scott7m on March 23, 2013, 09:05:57 PM
I guess the furnace could easily hit 220 if you ran it without water in it?

Oh yea no doubt... 

It says if the water jacket has exceeded 220 degrees..  Who would know how hot the water jacket had gotten?  I mean that's as clear as muddy water. 

Same way with the aquastat settings?  You could simply say, you operated the stove to cold and the discussion be over.  Only way to ensure they couldn't adjust things to dangerous levels is to have them pre set with pass codes, then there is still the factor of folks adding more things and killing return temps, that's where the thermo valves will come into play
Title: Re: More about operating temps
Post by: victor6deep on March 24, 2013, 02:41:55 PM
So a setting of 150-160 can be used.
Title: Re: More about operating temps
Post by: Scott7m on March 24, 2013, 03:18:05 PM
No

If your at 150 with a delta t of 20-30 degrees your return temps are going to be to cold

I was just showing that all companies are starting to notice the importance of it, it won't be long until you see that line in the warranty change to "boiler protection required" or "thermostatic valve required"

It takes the industry a while to catch up, cb has been doing this a while, empyre started last year requiring it, p and m, and several others have been offering them to customers and are in process of requiring these
Title: Re: More about operating temps
Post by: Scott7m on March 24, 2013, 03:23:06 PM
It wasn't long ago we had a discussion on here about a failed p and m, we found out at the farm show that customer had return temps of 105-115 degrees

Victor, if you set it at 150-160 and knew ur delta t could get no larger than 10, which is hard to do, I guess u could run it at those temps.  But why?  You have said yourself the firebox stayed cleaner and seemed to be more efficient at higher temps, another factor is the dissolved oxygen content in the water itself, the higher the temp up to like 175 is the lower the o2 content. 

I just don't see why it's wanted to run that 150 temp vs 180 when there is virtually nothing positive to come out of it. 
Title: Re: More about operating temps
Post by: MattyNH on March 24, 2013, 04:48:52 PM
Its like your gonna save any wood..The boiler is gonna work just as hard if was set at 150F vs 180F..Why not keep the temps up..
Title: Re: More about operating temps
Post by: yoderheating on March 24, 2013, 05:00:03 PM
Matt, when you have long underground pipe runs you save energy when you run lower temps.  Even when using quality insulated pipe it makes a difference. I did a service call on a furnace today that has over 400ft of pipe in the ground going to multiple buildings, on runs like that you see a difference. If you are running 50ft to a house its not that big a deal.
Title: Re: More about operating temps
Post by: Scott7m on March 24, 2013, 05:02:01 PM
Its like your gonna save any wood..The boiler is gonna work just as hard if was set at 150F vs 180F..Why not keep the temps up..

It beats me...  I've ran them both ways in the past and I can't say for certain if 180 uses more than 150, if it does it's not noticeable to me.  It sure doesn't change the btu demands of your home, that's for sure
Title: Re: More about operating temps
Post by: willieG on March 24, 2013, 05:07:14 PM
Its like your gonna save any wood..The boiler is gonna work just as hard if was set at 150F vs 180F..Why not keep the temps up..

It beats me...  I've ran them both ways in the past and I can't say for certain if 180 uses more than 150, if it does it's not noticeable to me.  It sure doesn't change the btu demands of your home, that's for sure

the savings of lower temps in the underground pipes will be a lower delta (the difference of the ground temp to the pipes temp.) if your water in the pipes is 180 and the ground is 50 there will more heat loss to the ground than if the water in the pipes was 160 and the ground temp was still 50, the difference in a short run as stated will not be much..in longer runs it would be more. but also as scott says you need to keep those return temps up too
Title: Re: More about operating temps
Post by: MattyNH on March 24, 2013, 05:54:11 PM
Matt, when you have long underground pipe runs you save energy when you run lower temps.  Even when using quality insulated pipe it makes a difference. I did a service call on a furnace today that has over 400ft of pipe in the ground going to multiple buildings, on runs like that you see a difference. If you are running 50ft to a house its not that big a deal.
How could you heat mulit building's with lower temps?? Esp in the dead of winter with wind chill factors ect..  I would think the wood boiler would never shut off..
Title: Re: More about operating temps
Post by: willieG on March 24, 2013, 06:13:45 PM
depending on insulation value  lets say you have  2000 square foot home that has 6 ich bats in your walls and cieling and good windows..you may need 40,000 btu per hour to heat that home on teh worst night of the year (just a number)  that would be 4 gpm at 180 degrees or you might say that 10 gpm at 160 degrees. (again just a number) could deliver the same amount of btu per hour

it is a largely accepted number(in the heating world) that 1 gpm of 180 degree water can deliver 10,000 btu of heat..so if you lowered the  temp of the water you would need to increase the flow to get the same amount of btu to the home.
Title: Re: More about operating temps
Post by: yoderheating on March 24, 2013, 06:25:41 PM
Many of my customers change the setting depending on the weather. Most would not be running a furnace at 150 when its really cold out. I normally drop mine down to 150 when it gets above 40 and you only need a little heat. I normally run mine at 180 during the coldest part of winter. Like I said before, I'm sure there is a huge difference between furnaces made of mild steel or furnaces without ash pans and stainless furnaces with ash pans. I can't speak for the former because Heat Master only makes stainless furnaces including the gassifiers. 
Title: Re: More about operating temps
Post by: MattyNH on March 24, 2013, 08:17:58 PM
Many of my customers change the setting depending on the weather. Most would not be running a furnace at 150 when its really cold out. I normally drop mine down to 150 when it gets above 40 and you only need a little heat. I normally run mine at 180 during the coldest part of winter. Like I said before, I'm sure there is a huge difference between furnaces made of mild steel or furnaces without ash pans and stainless furnaces with ash pans. I can't speak for the former because Heat Master only makes stainless furnaces including the gassifiers.
How much wood do you think your saving by dropping it down to 150? So you boiler fires back up at 140-145 to bring it back up to 150-155..Im only assuming what u have these set temps when its set at 150..Wouldn't you burn the same amount of wood  at set temp of 180F..(boiler on 170-175..off 180-185)..To me its the same burn time..Same wood consumption..
Title: Re: More about operating temps
Post by: victor6deep on March 24, 2013, 08:46:38 PM
Its like keeping a ice cube out in 80 degree weather or 60 degree weather, the colder outside the more times a stove will cycle to keep the temp up which in turn uses more wood.
Title: Re: More about operating temps
Post by: willieG on March 24, 2013, 08:58:45 PM
heat loss from your underground pipes is controlled by the delta and that is it.

if you have the pipes insulated there is still heat loss (agreed?)

if your water is 180 degrees and the ground tmeps are 180 degrees there would be no heat loss (fact..you should agree)

if your water was 180 degrees and the ground temp was 200 your water would actually warm up a bit(agreed?)

if your water was 180 and the ground was 50 there would be heat loss

if your water was 160 and the ground was 50 there would be less heat loss

if your water was 50 and the ground was 50 there would be no heat loss

this is based on teh water always moving the same gpm
Title: Re: More about operating temps
Post by: yoderheating on March 24, 2013, 09:20:50 PM
Willie, you are correct. Most insulated pipe companies have claims on heat loss. I know its not a lot when you use good pipe but every little bit adds up.
Title: Re: More about operating temps
Post by: willieG on March 24, 2013, 09:54:24 PM
Willie, you are correct. Most insulated pipe companies have claims on heat loss. I know its not a lot when you use good pipe but every little bit adds up.
take one pipe makers clain of a loss of just 1 degree in 100 feet of pipe at 5 gpm and a temp of 180 with a ground tmep of 32 degrees
that 1 degree comes from  about 40 pounds of water (5 gpm x 8 pounds a gallon) that is 40 btu loss to the ground per minute...60 min x 40 btu = 2400 btu per hour x 24 hours =57,600 btu per day x 150 (average days you run your OWB) = 8,640,000 btu lost to the ground for a heating season. that would work out to somewhere between (on a non gasser stove) 1/2 and 1 full cord of mixed hardwood

you are 100 percent right when you say "every little bit adds up"
Title: Re: More about operating temps
Post by: yoderheating on March 25, 2013, 06:23:07 AM
I run 180ft of pipe to my house, many people run a lot more than that. Like I said, it may not be huge but by the end of the year I'm ready to save all the firewood I can.
Title: Re: More about operating temps
Post by: chillyhiker on April 05, 2013, 09:32:57 AM
Saw this on a woodmaster in wv.....132 degrees ! 

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Title: Re: More about operating temps
Post by: victor6deep on April 05, 2013, 09:49:27 AM
I would say the majority of people around me are running 150-160. I know of a guy that runs his house and outbuilding at 120, I can only wonder when that thing is gonna start leaking. The coolest I will run is 160-170.
Title: Re: More about operating temps
Post by: Scott7m on April 05, 2013, 12:56:52 PM
Saw this on a woodmaster in wv.....132 degrees !

 Was he low on wood or what?
Title: Re: More about operating temps
Post by: chillyhiker on April 06, 2013, 08:13:17 AM
not sure.... it was at a road side stop ...they sell furniture,,,and i was just poking around while wife was inside. i didnt want to open the door. it was smoking a bit.
Title: Re: More about operating temps
Post by: victor6deep on April 06, 2013, 08:15:27 AM
Probably burning green wood which that's what those stoves are suppose to burn :bash:
Title: Re: More about operating temps
Post by: CRJR on April 06, 2013, 09:41:13 AM
i would guess somthing like this is how they would know if your stove got to hot
Title: Re: More about operating temps
Post by: CRJR on April 06, 2013, 09:45:08 AM
link didnt work but google this irreversible thermal temperature indicator
Title: Re: More about operating temps
Post by: victor6deep on October 08, 2014, 07:10:11 PM
Well, another heating season and the aquastat is locked at 150-165. I will let everyone know when it springs a leak, plan on buying a Ridgewood and doing the same thing. I know way to many people past 10yrs of use running 150-160 with zippo issues.
Title: Re: More about operating temps
Post by: LittleJohn on October 09, 2014, 06:26:25 AM
Currently running a CB eClassic 2400 @ 180f, with 10-15 delta T (forgot to look again, before posting)

This is how the water goes thru the system, after leaving boiler

4th year, no problems yet, other than a STUPID CHECK VALVE when installing Mechanical room in house
Title: Re: More about operating temps
Post by: slimjim on October 09, 2014, 07:13:52 AM
Well Victor you obviously know more about how they work than the guys building them, best of luck to you!
Title: Re: More about operating temps
Post by: fryedaddy on October 09, 2014, 01:27:02 PM
Doesn't this same topic keep popping up every year and end the same every year?