Outdoor Wood Furnace Info

All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: Allboutboost on October 30, 2012, 07:12:21 PM

Title: temp drop
Post by: Allboutboost on October 30, 2012, 07:12:21 PM
just out of curiosity what does everyone have there temp drop set at on there aquistat?
Title: Re: temp drop
Post by: sw18x on October 30, 2012, 07:35:05 PM
As low as possible based on my set up, and even set at 5 degree drop on the aquastat, I've found it's closer to 10 - 12 degrees drop before the blower actually kicks on. When I bought the house the burner was already there, and I inherited a set up that loses a solid 12 - 15 degrees by the time the water reaches the house. So if I run at 180, that's closer to 165 coming into the house, drop 10 degrees off that before the blower kicks trips and I'm at 155 degrees on the low end. We run baseboard heat with a gas boiler to supplement the wood burner, and I've got the gas boiler set to kick in when the water drops below 140. 155 is just enough to hold the water above 140 in moderately cold temps, if I could do it I'd run an actual 5 degree drop so the water coming into the house never drops below 160.
Title: Re: temp drop
Post by: willieG on October 30, 2012, 08:01:50 PM
you may have your aquastat set where ever you feel, except..(this is based on the cb valve that wont let water return to the boiler under 150 degrees)  you should make sure your return water is never less than 150

also you must take into account on how well your system can heat your home now. (and how fast your OWB can recover if your home is still using water when the OWB hits its' cut in temp) As you decrease the water temp you also drastically reduce the amount of btu's you are sending to your home.

some fin tube rads (base board heaters) give numbers like 650 btu per linear foot at 180 degrees and as low as 340 per linear foot 140 degrees
Title: Re: temp drop
Post by: jerkash on October 31, 2012, 04:21:57 AM
170 - 180
Title: Re: temp drop
Post by: Trint on October 31, 2012, 07:35:49 AM
170-185,  I have baseboard heat need to keep it high in colder weather, 160-175 in warmer weather. I have used anywhere from a 8-15 degree differential/temp drop, trying 15 now to try and get cleaner burns/longer burns
Title: Re: temp drop
Post by: husky 555 on October 31, 2012, 09:27:21 AM
Good lessons learned from Hurricane Sandy.  First and foremost I will no longer think of having my house and owb wired for a generator I will put that plan in action this evening after work.  I was without power for only 1 day but not having heat cannot be an option with 3 small kids.   My house only dropped to 62 degrees but had this been January of February could have been much worse.  Although not terrible cold in the house I was surprised at how long it took to heat back up. 

My owb temp is set to come on at 164 and off at 173 and this morning when I woke up the temp reading was 158.  My blower was on but when I opened the furnace I was surprised to see little wood actually burning.  I think the low temp reading was because my fuel had burned up quicker than I thought it would overnight. I was burning all dried Hemlock.  Second lesson learned.  Mix in some good harwoods.

Finally, as I search for a good generator does anyone have any recommendations.

Title: Re: temp drop
Post by: Allboutboost on October 31, 2012, 09:30:17 AM
I don't think you understand do you have it set to 5 10 15 degree temp drop before it fires up again.
Title: Re: temp drop
Post by: Scott7m on October 31, 2012, 09:33:55 AM
10 is a good number as a rule of thumb.  I advise customers to set them at 175-180 with 10 degree differentials
Title: Re: temp drop
Post by: woodman on October 31, 2012, 09:40:41 AM
Good lessons learned from Hurricane Sandy.  First and foremost I will no longer think of having my house and owb wired for a generator I will put that plan in action this evening after work.  I was without power for only 1 day but not having heat cannot be an option with 3 small kids.   My house only dropped to 62 degrees but had this been January of February could have been much worse.  Although not terrible cold in the house I was surprised at how long it took to heat back up. 

My owb temp is set to come on at 164 and off at 173 and this morning when I woke up the temp reading was 158.  My blower was on but when I opened the furnace I was surprised to see little wood actually burning.  I think the low temp reading was because my fuel had burned up quicker than I thought it would overnight. I was burning all dried Hemlock.  Second lesson learned.  Mix in some good harwoods.

Finally, as I search for a good generator does anyone have any recommendations.

I can run my entire house, including boiler off a 5500 watt troybuilt, I think it is rated at 8500 start up. Pretty simple setup as I backfeed it through a 220 volt outlet in my garage. Just make sure you turn off the main service or you send current down the line and would really screw things up if the power comes back on with the gen running. Oh and I keep a 30 degree swing for my setpoints.   
Title: Re: temp drop
Post by: AirForcePOL on October 31, 2012, 10:15:16 AM
Good lessons learned from Hurricane Sandy.  First and foremost I will no longer think of having my house and owb wired for a generator I will put that plan in action this evening after work.  I was without power for only 1 day but not having heat cannot be an option with 3 small kids.   My house only dropped to 62 degrees but had this been January of February could have been much worse.  Although not terrible cold in the house I was surprised at how long it took to heat back up. 

My owb temp is set to come on at 164 and off at 173 and this morning when I woke up the temp reading was 158.  My blower was on but when I opened the furnace I was surprised to see little wood actually burning.  I think the low temp reading was because my fuel had burned up quicker than I thought it would overnight. I was burning all dried Hemlock.  Second lesson learned.  Mix in some good harwoods.

Finally, as I search for a good generator does anyone have any recommendations.

I can run my entire house, including boiler off a 5500 watt troybuilt, I think it is rated at 8500 start up. Pretty simple setup as I backfeed it through a 220 volt outlet in my garage. Just make sure you turn off the main service or you send current down the line and would really screw things up if the power comes back on with the gen running. Oh and I keep a 30 degree swing for my setpoints.

Not only that but you would be sending power back through the lines that someone could be trying to hook back up, and thinking that they aren't energized!
Title: Re: temp drop
Post by: woodman on October 31, 2012, 10:29:26 AM
Good lessons learned from Hurricane Sandy.  First and foremost I will no longer think of having my house and owb wired for a generator I will put that plan in action this evening after work.  I was without power for only 1 day but not having heat cannot be an option with 3 small kids.   My house only dropped to 62 degrees but had this been January of February could have been much worse.  Although not terrible cold in the house I was surprised at how long it took to heat back up. 

My owb temp is set to come on at 164 and off at 173 and this morning when I woke up the temp reading was 158.  My blower was on but when I opened the furnace I was surprised to see little wood actually burning.  I think the low temp reading was because my fuel had burned up quicker than I thought it would overnight. I was burning all dried Hemlock.  Second lesson learned.  Mix in some good harwoods.

Finally, as I search for a good generator does anyone have any recommendations.

I can run my entire house, including boiler off a 5500 watt troybuilt, I think it is rated at 8500 start up. Pretty simple setup as I backfeed it through a 220 volt outlet in my garage. Just make sure you turn off the main service or you send current down the line and would really screw things up if the power comes back on with the gen running. Oh and I keep a 30 degree swing for my setpoints.

Not only that but you would be sending power back through the lines that someone could be trying to hook back up, and thinking that they aren't energized!

Thats what I meant when I said "you could send power down the line". Definatly not a setup if you don't have a basic understanding of electricity but works well for me and is safe.
Title: Re: temp drop
Post by: husky 555 on October 31, 2012, 11:10:11 AM
I will have a qualified electrician do the install to be safe
Title: Re: temp drop
Post by: AirForcePOL on October 31, 2012, 12:17:00 PM
Good lessons learned from Hurricane Sandy.  First and foremost I will no longer think of having my house and owb wired for a generator I will put that plan in action this evening after work.  I was without power for only 1 day but not having heat cannot be an option with 3 small kids.   My house only dropped to 62 degrees but had this been January of February could have been much worse.  Although not terrible cold in the house I was surprised at how long it took to heat back up. 

My owb temp is set to come on at 164 and off at 173 and this morning when I woke up the temp reading was 158.  My blower was on but when I opened the furnace I was surprised to see little wood actually burning.  I think the low temp reading was because my fuel had burned up quicker than I thought it would overnight. I was burning all dried Hemlock.  Second lesson learned.  Mix in some good harwoods.

Finally, as I search for a good generator does anyone have any recommendations.

I can run my entire house, including boiler off a 5500 watt troybuilt, I think it is rated at 8500 start up. Pretty simple setup as I backfeed it through a 220 volt outlet in my garage. Just make sure you turn off the main service or you send current down the line and would really screw things up if the power comes back on with the gen running. Oh and I keep a 30 degree swing for my setpoints.

Not only that but you would be sending power back through the lines that someone could be trying to hook back up, and thinking that they aren't energized!

Thats what I meant when I said "you could send power down the line". Definatly not a setup if you don't have a basic understanding of electricity but works well for me and is safe.

Yea I figured that's what you meant.  I've got a transfer switch at my house so that when I get a generator there is no way to send power back through the power lines because you have to have the main breaker off in order to turn the service on from the generator. 
Title: Re: temp drop
Post by: woodman on October 31, 2012, 12:58:19 PM
Good lessons learned from Hurricane Sandy.  First and foremost I will no longer think of having my house and owb wired for a generator I will put that plan in action this evening after work.  I was without power for only 1 day but not having heat cannot be an option with 3 small kids.   My house only dropped to 62 degrees but had this been January of February could have been much worse.  Although not terrible cold in the house I was surprised at how long it took to heat back up. 

My owb temp is set to come on at 164 and off at 173 and this morning when I woke up the temp reading was 158.  My blower was on but when I opened the furnace I was surprised to see little wood actually burning.  I think the low temp reading was because my fuel had burned up quicker than I thought it would overnight. I was burning all dried Hemlock.  Second lesson learned.  Mix in some good harwoods.

Finally, as I search for a good generator does anyone have any recommendations.

I can run my entire house, including boiler off a 5500 watt troybuilt, I think it is rated at 8500 start up. Pretty simple setup as I backfeed it through a 220 volt outlet in my garage. Just make sure you turn off the main service or you send current down the line and would really screw things up if the power comes back on with the gen running. Oh and I keep a 30 degree swing for my setpoints.

Not only that but you would be sending power back through the lines that someone could be trying to hook back up, and thinking that they aren't energized!

Thats what I meant when I said "you could send power down the line". Definatly not a setup if you don't have a basic understanding of electricity but works well for me and is safe.

Yea I figured that's what you meant.  I've got a transfer switch at my house so that when I get a generator there is no way to send power back through the power lines because you have to have the main breaker off in order to turn the service on from the generator.

Yep, that is the right way to do it. Whenever I hook mine up I always double and triple check that the main is off before I start the generator up. Oh and I guess I should also note that when I built my house I wired a seperate 8 gauge wire just for this and if I ever wanted a welder in the garage. Wouldn't want to sent all that juice through a 12 or 10 gauge. 
Title: Re: temp drop
Post by: victor6deep on January 20, 2014, 07:37:07 PM
10 is a good number as a rule of thumb.  I advise customers to set them at 175-180 with 10 degree differentials

Buddy Scott, you still advise 10 degree diffs over 15 on conventional stoves?