Outdoor Wood Furnace Info

All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: arkgac5 on October 27, 2009, 06:02:38 PM

Title: Suggested Water Temperature on Boiler
Post by: arkgac5 on October 27, 2009, 06:02:38 PM
I have a Shaver 165 purchased in 2007.  Last season I added a damper / solenoid on the fan to get better burn, and to close up the fan opening when the boiler thermostat is not calling for more heat.

My question is what is the optimum water temperature for the boiler to get a good burn. The factory owner suggested 140 was best. The shutter style damper required a low setting as the draft would cause the boiler water to steam off if little heat demand was required, such as in warmer weather.

Will a setting of 160-180 deg. provide for a better burn / less smoke than the 140 deg? I believe that the Hardy Heaters state that 180 deg. will provide a better fire restart when more heat is required.

I just replaced the factory RTV upper door gasket with a fiberglass rope gasket. The ash door gasket was replaced with RTV material. I also applied RTV sealant to the flange on the draft fan. This has almost eliminated any drafts, which cause the water temp to rise when the draft fan is off.

On the Hardys Heaters, I have noticed they have very little or no draft when they are at idle. I have not been able to replicate this on my Shaver. Maybe I am geting some draft through the motor windings on the draft fan.


Thanks
Jerry






Title: Re: Suggested Water Temperature on Boiler
Post by: ckbetz on October 27, 2009, 06:36:42 PM
Hey Jerry,

Welcome to the forum.  I have a Central Boiler that shuts down similarly to a Hardy I would say.  CB recommends that you don't set your water temp below 165 in order for the boiler steel to keep from coollng too much and then heating way up from the fire.  Since I don't have a forced induction fan this also helps get the fire burning a little quicker since the heat creates a bit more draft.  I'm sure they've done some tests on it, Central Boiler seems to pride themselves on the amount of testing they have done.  I also know that a lot of thermal expansion (and contraction) can be very hard on steel, especially stainless.  That said, I tend to run mine at a little lower temp. because I have the large surface area radiators so I simply don't need a high heat like baseboard.  When the temperature outside gets down to where the highs during the day are in the 20's then I'll bump mine up to 185 or so.  Hope that gives you something to chew on...good luck.
Title: Re: Suggested Water Temperature on Boiler
Post by: arkgac5 on October 27, 2009, 07:29:11 PM
ckbetz,

Thanks for the reply. Have not considered the expansion / contraction cycles of the metal. Going to up my setting to 165 and see if boiler water starts to steam out the overflow tube.

Jerry
Title: Re: Suggested Water Temperature on Boiler
Post by: willieG on October 27, 2009, 07:48:25 PM


On the Hardys Heaters, I have noticed they have very little or no draft when they are at idle. I have not been able to replicate this on my Shaver. Maybe I am geting some draft through the motor windings on the draft fan.


Thanks
Jerry

jerrymy OWB is home made i had the same problem first try ..there was enough air getting through the windings to cause a boil over on a windy day.. i fixed this by putting my draft hole in a box with a rod going through it so the solenoie would lift the cover  when called for, and the blower outside the box blowing in..this way when the solenoid opened and dropped the lid on the draft hole the motor is outside and can not deliver air through the windings

if this explanation is not clear i can find a photo and put up on the photo site h ere





Title: Re: Suggested Water Temperature on Boiler
Post by: arkgac5 on October 28, 2009, 11:01:38 AM
willieg,
Thanks for the feedback. Good idea on the fan box. This should take care of my draft. I saw a similiar set-up on a door fan in the Home Made furnace forum.

I read some of the posts in the Shaver forum. Sounds like a few had bad experiences with Shaver. I ordered my furnace in early September 2007 and received it the last week in November 2007. I traveled to the factory on a Saturday morning and met with Billy Shaver. The factory looked like a welding shop. No better or worse than most other metal working shops I have been in. Their customer / technical service needs improvement. No excuse for not returning phone calls.

Overall my experience has been ok with the Shaver 165. It does need some improvements like the draft fan. As long as the welds hold up and gets proper care, this furnace should last me a long time.

Jerry
Title: Re: Suggested Water Temperature on Boiler
Post by: mikenc on October 29, 2009, 06:43:03 AM
Jerry I have a NCB-175. Temp is set at 150 during warmer weather. My fan has gasket over intake  opening to stop air flow during fan off cycle. Seems to work, have no problem with temp rising during off time.
Will probably go up when weather turns colder to 160-165. higher if needed. I have hot water boiler in basement oil fired. Ran it at 180 before I installed OWB. As long as water is hot enough to keep house warm, domestic water heated I think it is ok.
Just play with it some and see where you get the best burn for your OWB. I have read that every OWB is a little different.
One thing I have noticed to much air, heat goes right up chimney.
Title: Re: Suggested Water Temperature on Boiler
Post by: anightd on November 26, 2009, 07:12:38 PM
I don't understand the impact on the outside temperature on how hot the water is. Does the until tend to bring the water temperature up more effeciently when it gets colder outside? Why and how does that happen?
Title: Re: Suggested Water Temperature on Boiler
Post by: MarkP on November 27, 2009, 08:07:39 AM
We are having nighttime temps. in the mid 30s to mid 40s here in WV most nights, and I'm still running my water temp at 135 max with no issues.  The water temp goes down to 115 before the draft fan kicks on.  I'm heating my house and garage, and loading the stove "light" twice a day, or fill it and not have to worry with it for a day or so.  If I have a little smoke,,, I don't have to worry about it.  I think keeping the water temp low should save some wood. 
Title: Re: Suggested Water Temperature on Boiler
Post by: boyland on December 14, 2009, 10:41:02 PM
The reason the temp is recommended at 160 is because at below 153 boilers tend condensate causing rust.

Has nothing to do with cooling steel bs.

Blaine
Title: Re: Suggested Water Temperature on Boiler
Post by: pdboilermaker on December 16, 2009, 01:44:26 PM
I have a woodmaster 4400 and I adjust my temps to the weather.  It helps me save a lot of wood.  My big problem is high winds, low temps not so much.  So if it is in the 30-40 deg range outside and no wind, I run water temp at 130low - 140high, if it is in the same temp range but really windy, I run in the 150low - 160high range.  If below 0-30 but no wind I run in the 150low - 160high range and when temps are 0-30 with wind I pull out all the stops and run in the 170low - 180 high range
Title: Re: Suggested Water Temperature on Boiler
Post by: woodywoodchucker on December 20, 2009, 06:26:35 AM
I set my cb5036 at 190 and seems to like it. Recovery time is reduced and it has a muck more complete burn.
Title: Re: Suggested Water Temperature on Boiler
Post by: jon d on December 24, 2009, 07:09:21 PM
Woody, how many cords do you use up in Maine?? And do u lower your boiler temp. when outdoor temps are in their 40-50s.
Title: Re: Suggested Water Temperature on Boiler
Post by: woodywoodchucker on December 25, 2009, 03:28:41 AM
I have burnt about 4 cords from Oct. to now.I can totaly fill the CB once a day during the warmer times, 30 to 50 degs.However yesterday was the first day above 32 degs. in 8 days.At 0 to 20 I fill 3 times a day.Im burning wet wood thow. Not having time to buck up wood last year is hurting the performance of the boiler.Tomorrow Im falling some trees and getting a start on next years wood pile.Oh,hey, Merry xmas to all
Title: Re: Suggested Water Temperature on Boiler
Post by: maine owb on December 28, 2009, 06:49:10 PM
I have played with my water temp and I have decided when it is cold, 20 degrees and under i keep it at 185, by the time it gets in my house 75' away it loses 10 degrees and then when all my zones use it i need all of it, especially the dom hot water. When it is above 20 degrees i keep it at 180. At any given point the temp could be 10 degrees below that(boiler temp) until the fan turns on. I did not notice much of a difference keeping it at 160 or 165 except it caused a bit more smoke at start up. I only use this in the winter.
Title: Re: Suggested Water Temperature on Boiler
Post by: R W Ohio on December 29, 2009, 05:37:26 AM
The last three years I had the on temp. set at 170°F and the off at 185°F. But this year I changed the settings to 160°F on and 170°F off. So far it seems to be working well with these settings and may be using a little less wood.
Title: Wood Usage in Maine
Post by: maine owb on December 30, 2009, 05:13:48 PM
I noticed a response about wood usage in maine, I have an ASPEN 175 now called an empyre by pro fab and I use
1 and 1/3 cord per month during Dec, Jan,Feb, and March. I burn wood until mid May, the total I use is between 6 and 7 cords.
My house is 3300 sqaure feet including the garage that i keep at 60 degrees, this also includes my Hot water. I keep a daily journal
on temp/loading times and wood types used and it is pretty predictable.

I load my wood twice per day, once at about 8:00 AM and then again at about 7:30 PM no matter how cold it is outside.

My wood boiler is connected to my maine heating system via a heat exchanger. I have a 30% glycol mix with the total system
being about 80 gallons. My circulator will shut down at 120 degrees(fire dies) and come back on at 40 degrees as an added protection against
freezing. It would take a small amount of heat from my oil backup. I also have a dump zone inside my basement incase of overheating but this has only come on a couple times since last year. The glycol helps with freezing but also makes the boiling point higher as well. My boiler is 75' from the house and is connected to the house using 1 and 1/4" pex, 3' deep. I insulated it with standard pipe insulation, then wrapped it in reflex bubble insulation and the feed that into 4" solid drainage pvc, one for the supply and one for the return(very little heat lose). You cant tell where the lines are when it snows like some peoples indicating heat lose.

I burn well seasoned and dry wood only, this also creates little smoke most of the time.

love to talk shop with anyone interested, always looking to make things better.