OWB Water temps

[Cbird14]

Hey fellers. The wife and I put in a OWB this September and am just curious what temp u all have set on your aquastat? I have mine set at 175°. I'm heating our 2700sqft house, the hot water and our 28'x52' shop/garage. Just wondering if anyone has found a "sweet spot". My ma n dad have had a OWB since 1990 and always had it set at 180°. That old heat-mor is/was a wood eating pig.

 

[deutzman]

I vary the water temp. setpoint with the weather. I also burn year round. Summer 170, fall 175, temps 25-30/180 and below 20/185.

 

[motoman3b]

I played around a little bit but found 145 works best for me, 24 hour burns since I've been running on that temp with half way seasoned hardwood. I'm heated dhw and forced air funace 1600 sq ft and sometimes have the 1200 sq ft garage heated when im working out there

 

[rev_2004]

I also burn year round except for July & August. Summer I heat the pool & normally run @165, 175 -180 in normal heating conditions, below 15-20 I normally take it to 185. As far as a sweet spot I think it differs with outside temp.

 

[idahohay]

Hey fellers. The wife and I put in a OWB this September and am just curious what temp u all have set on your aquastat? I have mine set at 175°. I'm heating our 2700sqft house, the hot water and our 28'x52' shop/garage. Just wondering if anyone has found a "sweet spot". My ma n dad have had a OWB since 1990 and always had it set at 180°. That old heat-mor is/was a wood eating pig.

Cbird, I would just set it at what the manufacturer recommends. If your return temps get below 140-150 the increased amounts of condensation in the boiler and increased oxygen in the water lead to shorter boiler life.

The most common reasons for lowering the cutoff temp. would be to prevent overshooting in times of low heat demand, return temps considerably above 150(if heat demand is being met-no need to maintain a higher temp).

Sounds like you have a large demand on your boiler so expect you burn a lot of wood. Your mom n dads "wood pig" is burning lots of wood for a reason. Lots of square footage, poor insulation and windows, a poorly insulated line between boiler and house, are the usual reasons for excessive wood consumption.

 

[John R]

I run mine 145° on --165° off, works well.
I heat a 2000 sq foot house, DHW, and my barn when I'm out there working.
I always keep my barn around 40°

 

[Cbird14]

Cbird, I would just set it at what the manufacturer recommends. If your return temps get below 140-150 the increased amounts of condensation in the boiler and increased oxygen in the water lead to shorter boiler life.

The most common reasons for lowering the cutoff temp. would be to prevent overshooting in times of low heat demand, return temps considerably above 150(if heat demand is being met-no need to maintain a higher temp).

Sounds like you have a large demand on your boiler so expect you burn a lot of wood. Your mom n dads "wood pig" is burning lots of wood for a reason. Lots of square footage, poor insulation and windows, a poorly insulated line between boiler and house, are the usual reasons for excessive wood consumption.

Old heat-mors are known for burning alotta wood. They have a 2500 or so sqft house. And heated dhw. Shortly after the installed the OWB they reinsulated the attic. And put in new windows around the same time. Everyone I've talked to that has had a heat mor and switched to a diff brand has said they were wood pigs

 

[Cbird14]

Cbird, I would just set it at what the manufacturer recommends. If your return temps get below 140-150 the increased amounts of condensation in the boiler and increased oxygen in the water lead to shorter boiler life.

The most common reasons for lowering the cutoff temp. would be to prevent overshooting in times of low heat demand, return temps considerably above 150(if heat demand is being met-no need to maintain a higher temp).

Sounds like you have a large demand on your boiler so expect you burn a lot of wood. Your mom n dads "wood pig" is burning lots of wood for a reason. Lots of square footage, poor insulation and windows, a poorly insulated line between boiler and house, are the usual reasons for excessive wood consumption.

thanks for the return temp Info. I'll have to put a temp gauge on one of the return lines. I keep the shop around 55° and unless it gets below zero the blower in the shop rarely kicks on. Just the heat from the lines running across the ceiling and running thru the heat exchanger keeps it warm.

 

[idahohay]

Old heat-mors are known for burning alotta wood. They have a 2500 or so sqft house. And heated dhw. Shortly after the installed the OWB they reinsulated the attic. And put in new windows around the same time. Everyone I've talked to that has had a heat mor and switched to a diff brand has said they were wood pigs

I know somebody that has a heatmor and it is a wood pig because he made the the pipe from boiler to building himself and it loses typically 5 degrees from the boiler to inside the building. You can tell exactly where his pipe runs when there is snow on the ground( no snow where his pipe run is) When I originally talked to him about it he thought it was a free snow melt system and it was cool but I'm guessing he burns an extra 6 cords of wood a year.

Poorly insulated underground pipe is the most common mistake made installing OWB's.

 

[ash man]

I keep mine on 175 and kicks back on at 168. I made my own lines and buried them at 3'. I always figured i was losing alot of heat on the 125' run to the house, but the snow isnt melted over the lines. Do you guys think im ok?

 

[Speed]

Cbird, I would just set it at what the manufacturer recommends. If your return temps get below 140-150 the increased amounts of condensation in the boiler and increased oxygen in the water lead to shorter boiler life.

The most common reasons for lowering the cutoff temp. would be to prevent overshooting in times of low heat demand, return temps considerably above 150(if heat demand is being met-no need to maintain a higher temp).

Sounds like you have a large demand on your boiler so expect you burn a lot of wood. Your mom n dads "wood pig" is burning lots of wood for a reason. Lots of square footage, poor insulation and windows, a poorly insulated line between boiler and house, are the usual reasons for excessive wood consumption.

+1 on this. You don't want your return coming back below 140° or the condensation will bring an early death to your owb. Just because you are running at hotter temp doesn't mean you'll burn more wood. The fire is only going to burn to bring temp back up to set point, to reheat water the 10-15° between differentials. Myself, I prefer 180° with a 165° low for a little safety net on the bottom in case it gets hit with a load right at the kick on point so the fire can get going in time.

 

[Speed]

I keep mine on 175 and kicks back on at 168. I made my own lines and buried them at 3'. I always figured i was losing alot of heat on the 125' run to the house, but the snow isnt melted over the lines. Do you guys think im ok?

Yeah, you seem ok.

Wait did you mean your stove?

If you aren't seeing snow melt i would guess you're lines are alright. Can you get your hands on a thermometer? Like one of those laser/infrared point and shoot ones? That will take the guessing out of it.

 

[Cbird14]

I will be turning up the aquastat tomorrow morning to 180-182° definitely don't wanna send the stove to its death early in life

 

[Cbird14]

I'm thinking of putting a temp gauge on the return line next to the stove on the house run this spring.

 

[ash man]

Speed ive been meaning to get one of those infrared thermo, for peace of mind but havnt yet

 

[Speed]

When using one, use on the metal. The plastic won't read true, due to its insulating properties.

 

[ash man]

K thanks speed

 

[showrguy]

+1 on this. You don't want your return coming back below 140° or the condensation will bring an early death to your owb. Just because you are running at hotter temp doesn't mean you'll burn more wood. The fire is only going to burn to bring temp back up to set point, to reheat water the 10-15° between differentials. Myself, I prefer 180° with a 165° low for a little safety net on the bottom in case it gets hit with a load right at the kick on point so the fire can get going in time.

sorry, but i really don't agree with you on this..
my mahoning 400 only burns in the heating season, but, it is set @ 185-190 when temps are/average below 30 F.(now)... it supplies a 125 gal. nurse tank in the basement that is set at 140 this time of year...
so my return temp has NEVER been above 140 deg, i'm heating about a 5600 sq. ft. house, and another 1800 sq. ft. garage (when i turn it on)..
the house was built with radiant heat in mind, so it's all radiant floor heat, including garage slab, and basement slab (basement has'nt been on since i built the house)..
i'm now on my 12th heating season with no major issues........ i figure the owb paid for itself by the second season..

i dunno what your talking about when you say "condensation" will bring an early death to my owb ???
mine is an open system btw..

 

[Cbird14]

Speed ive been meaning to get one of those infrared thermo, for peace of mind but havnt yet

The wife bought me one for a early Christmas gift. Very handy to have around the shop

 

[NSMaple1]

sorry, but i really don't agree with you on this..
my mahoning 400 only burns in the heating season, but, it is set @ 185-190 when temps are/average below 30 F.(now)... it supplies a 125 gal. nurse tank in the basement that is set at 140 this time of year...
so my return temp has NEVER been above 140 deg, i'm heating about a 5600 sq. ft. house, and another 1800 sq. ft. garage (when i turn it on)..
the house was built with radiant heat in mind, so it's all radiant floor heat, including garage slab, and basement slab (basement has'nt been on since i built the house)..
i'm now on my 12th heating season with no major issues........ i figure the owb paid for itself by the second season..

i dunno what your talking about when you say "condensation" will bring an early death to my owb ???
mine is an open system btw..

I don't know anything about a Mahoning first-hand, but chances are it has some return protection built-in? Somehow mixes some hot supply water into the cold return water just before the return water enters the bottom of the boiler?

If not, it's a poor design & you've been lucky. It's pretty well known that water below 140° entering into the bottom of a wood boiler will cause increased creosote condensation inside the boiler & lead to premature corrosion. Even my old inefficient indoor boiler I got 18 years ago had a recirc pump on it that kept the return-in warm by mixing via a bypass.