# Outdoor Wood Boiler Users. And Everyone Else.



## Biglurr54 (Jan 7, 2014)

I have been playing with my owb settings. I've noticed I have huge efficiency gains when I drop the shut off temp to 165 vs 185. When the weather is bitter cold like right now (upstate ny) I bring my temp up to get the heat in the house faster. During mild temps I I turn it down to 165 to gain the efficiency. Anyone else notice or try this? Also i messed with the temp diff. (Point that fan turns on). Again I have found d better efficiency's at 15 degree diff compared to 10 degree diff. My worry with this is could the larger temp swings put stress on the metal and joints due to expansion and contraction. I have heard the reason oil boilers are set with such small diff.s is because the varying heat contractions can fatigue the cast iron boilers. Any thoughts on this?


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## phantomblack (Jan 7, 2014)

I run my central boiler at 185 shut off temp with a 174 turn on temp. Cental boiler recommends 185. I'm guessing it is to keep any condensation under control in the fire box to reduce chances or corrosion. When I have ran my boiler at a lower temp I did not see any change in wood use, just more smoke. 

Just watch your return water temp when running that low. I think that the rule of thumb is to keep the return water temp over 150 to reduce condensation in the firebox. For me, wood is free and boilers are expensive. I run the set points that the owners guide tells me to.


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## Cheesecutter (Jan 7, 2014)

I tried running 165/155 and found the house furnace blower fan ran twice as long as it does when it's set at 180/170. It also struggled to hold temp as well. I didn't seem to burn much more wood at the higher temps so I leave it there. I do bump it up to 185/175 when it is below zero to help with recovery times from heating 2 houses.


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## Biglurr54 (Jan 7, 2014)

How do you check line temps? I wrapped an outdoor wireless thermometer sending unit with insulation on the line in and only get a temp of 130 when the boiler is at 185.


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## Cheesecutter (Jan 7, 2014)

I use an infra-red thermometer. It's a handy little gadget for $25.


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## Biglurr54 (Jan 7, 2014)

Yea. I've been meaning to pic one up. The pex doesn't offer any insulation? I feel like the pex won't be the same temp as the water passing through it.


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## Poston5 (Jan 7, 2014)

I notice a savings in wood when I turn my temp down. But with it being this cold I cranked it up some. I run a five degree differential.


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## StihlFroling (Jan 10, 2014)

Look up outdoor reset control, it adjust boiler temp according to outside temp, and can save up to 40% in fuel! but usually around 15%.


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## Butch(OH) (Jan 10, 2014)

Same here with the Woodmaster. We run ours at 160-170 most of the time but turn it up to 170-180 when it gets below zero and down to 155-165 when we dont need much heat. There is a nice savings in wood, guessing 10% by running 10 degrees lower. Central Boiler wont let you run cooler than 180 with that automatic valve you have to install now, I dont like them!


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## Speed (Jan 11, 2014)

Keep an eye on your water quality running these lower temps. There was a guy on another site that kept preaching that low temps were fine(150-160) and no need to run 180. Well, the other day he posted that he was noticing green slime build up even though his water tests showed proper readings. He contacted Central Boiler about this, and tech told him this is just another reason they recommend the higher temps. He said after bumping to 180 the slime is going away. 

Just sayin. And per the Whitespider precedent, nobody can argue, its my birthday.


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## wrh51 (Jan 11, 2014)

I have noticed I save a significant amount of wood during milder weather by keeping the water temp at 150. My OWB is home made and not a factory unit which may make some difference. I also set my water temp differential at 2 degrees. When I had it set at 15, the fire would rage and the temp would overshoot my high set point. My OWB is probably not insulated as well as factory units. So I was basically heating up water that I didn't need to keep up with the house's heat demand. So alot of that energy was being lost outside at the unit. At a 2 degree differential my blower runs for shorter times. My thinking is that the more or longer the blower runs the more heat you are pushing out of the firebox. I live in an older poorly insulated house. When it is very cold, like earlier this week. I turn the water temp up to 185 but still keep the diffential at 2 degree. Again, less blower run time, less heat being pushed out of the firebox.


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## legg28 (Jan 11, 2014)

Butch(OH) said:


> Same here with the Woodmaster. We run ours at 160-170 most of the time but turn it up to 170-180 when it gets below zero and down to 155-165 when we dont need much heat. There is a nice savings in wood, guessing 10% by running 10 degrees lower. Central Boiler wont let you run cooler than 180 with that automatic valve you have to install now, I dont like them!


 My CB has the thermostatic valve and as long as the water temp is above 150 or 155 ( its one or the other ) water will flow to the hot water tank and heat exchanger. Unless they changed it in the last couple years .


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## gunny100 (Jan 11, 2014)

whats the best out side bolier firewood burner to buy
how many time per week do you fill up your bolier with wood

do you burn any kind of wood


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## cantoo (Jan 11, 2014)

It's been warmer here the last 2 days but I decided to bump up my owb setting to 170 from the 150 to 160 I was running it at before. I'm using a Pacofic Western stainless model. I cleaned my ashes out for the 1st time and really didn't need to but I burned a ton of wood with nails in it and wanted to clean it out. I just pulled out 5 cherry rounds about 10"x 3' long, they were about 3/4 burnt and had embers on them so I set them beside the stove while I emptied it out. I took a look inside and it is full of crap on the sides and the top was black and sticky. Last fall when I had it running at 180 for a month the inside was spotless and smooth then I turned it down to 150. We really don't have the heat draw so I expect it won't be firing much I hope it stays lit between calls for heat.


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## Cheesecutter (Jan 12, 2014)

gunny100 said:


> whats the best out side bolier firewood burner to buy
> how many time per week do you fill up your bolier with wood
> 
> do you burn any kind of wood


Welcome to AS Gunny. There are a lot of threads about which is the best boiler (OWB)Central Boiler, Portage and Main, Heatmor, etc... Generally the best answer comes down to the brands that have been around for decades and a quality local dealer. Most guys load them twice per day (8-24 hour burn times depending on temp). Yes, you can burn pretty much any kind of wood in them, but seasoned and dry wood is best. Some guys would burn "anything that will fit, wet or dry", so now a lot of communities are regulating and banning OWBs because of the smoke. They do eat a lot of wood, depending on what you're heating...6-20 cords or more per year.


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## NSMaple1 (Jan 12, 2014)

Temps are a balancing act.

Hotter works better for cleaner burning & getting enough heat in the house, but it also sends more heat into the atmosphere via increased heat loss.


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## [email protected] (Jan 12, 2014)

Guys, todays boilers for the most part are far different than the old conventional boilers, you can see this clearly in stack temps, a conventional boiler at 185 can run stack temps as high as 1200 degrees where for example our 250 gasser at water temp of 195 will run stack temps of between 260 and 320 depending on how dirty the heat exchanger is and how much air it is given, in the off cycle the stove goes dormant with no air coming into the burn chamber and very little heat loss up the stack. If you have one of the gassers, you will find very little difference in wood consumption with hotter temps and the stove will perform much better at temps over 190 degrees.


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## cantoo (Jan 12, 2014)

So I turned up the temp to about 175. I was just over at my other house and the pump is so hot you can hardly touch it and it's making a whining sound once in awhile. It's a Grundfos 3 speed and was new in October and runs continuous. I have the same pump in this house and it's also too hot to touch but not making much noise. I realize the pump will be as hot as the water but man that has to be hard on the thing. I'll likely pick up another and replace the noisy one and keep it as back up. Both pumps are inside the house so changing is no problem. It's still relatively warm here so not much heat draw to either house.


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## Marklambert61 (Jan 13, 2014)

My heatmor runs best at 165 to170 in winter best wood saving idea I found was to reduce chimney outlett to 3" dia. rather than mess with water temp.
If you run cooler than 165 to170 you will have buildup issues with most boilers.

Mark


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## CBwoodheat (Feb 24, 2014)

cantoo said:


> So I turned up the temp to about 175. I was just over at my other house and the pump is so hot you can hardly touch it and it's making a whining sound once in awhile. It's a Grundfos 3 speed and was new in October and runs continuous. I have the same pump in this house and it's also too hot to touch but not making much noise. I realize the pump will be as hot as the water but man that has to be hard on the thing. I'll likely pick up another and replace the noisy one and keep it as back up. Both pumps are inside the house so changing is no problem. It's still relatively warm here so not much heat draw to either house.


whining pump is usually an indication of air trapped around the shaft
try turning the pump to med and bumping it with a closed fist (meaty side of the hand) 

that may dislodge the air.... then turn it back to high if you need to
where are the pumps in relation to the water level in the stove (if you sight level from the water level in the stove to the level of the pump is the pump lower by 1 foot or 10 ft or is it possibly higher.

these pumps like to push not pull and should be low when compared to water level in the stove


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