What temps do you run your OWB?

[Butch(OH)]

Just a poll here I guess. Mine was factory set at 160 on/170 off. I raised it to 165-175 to see if it would heat my dometic water a little faster which it did. Is there any reason to play with the temps? Would it help with keeping the firebox cleaner or corrosion?

 

[Corley5]

My draft blower goes off at 180 and comes on at 170 this time of year. In the spring and fall I turn it down to 150/140.

 

[Husky137]

Heating season, 175-185, hot water season,165-175.

 

[MS-310]

185 to 175.... works well I have turned it up to 200 and 190 for the hot tube use.... fast recovery, I have a small exchanger on it and dont want to change it cuz it fits well.

 

[ghitch75]

we run ours at 180 off 160 on and yes a higher setting will help keep the fire box cleaner...Butch how do you have you water heater piped?...

 

[Powerlineman]

My aquastat is set to open the draft door at 170 and close at 180.

 

[windthrown]

185 factory setting...

Central Boiler uses a factory setting of 185 F. Supposedly the higher the setting, the more efficient the system. CB will allow for setting from 165 to 195. Above 195 gets pretty close to boiling if the damper closes at 195 and it overshoots in temp.

I set our OWB at 165 F. It will open the damper at 155 F and maybe drop to 150 before going back up. It will go off at 165 F and usually overshoot to about 170 F before leveling off. We have a hydronic floor heating system and hardwood and tile floors in the house. With hard surface flooring you do not want to go much above 100 F for heating, and so I set the mixing valve to 100 on the floor heating loop. Most HXs will drop the temp about 20 degrees in use, so at 165 we get between 130-150 F in the hot water convection loop. More than enough to heat the hot water here. The floor loop HX has pleanty of heat after that and is mixed down to 100 F anyway, so no need for higher boiler temp that I have found here with this sytem that I installed.

If you have a hydronic system with carpets you may need to set the mixing valve as high as 140 in the floor loop. In that case the boiler temp would need to be set higher. Also if the boiler loop temp is higher the recovery time is faster for hot water heating, and you have more heat stored or heating the house when the fire dies out.

 

[Puumies]

Off topic

From what words OWB is shortened? I have a clue, but it would be nice to know exactly. Easier to understand your writings.

Thanks, Pauli

 

[Butch(OH)]

From what words OWB is shortened? I have a clue, but it would be nice to know exactly. Easier to understand your writings.

Thanks, Pauli

OWB= Outdoor wood boiler, sorry

 

[MS-310]

I've read that higher temperatures are better because at low temperatures condensation can form on the cold walls inside the fire box and it is very corrosive.

Condensation will form but not set there long enough to make it a big deal.(steams off) but if you run your boiler hotter you will have less cleaning of the box it self. I do like to some times put some newspaper in it and let the stove fire hot and clean its self. Its like an self cleaning cooking stove...kinda LOL.

Of the topic. tree CO. the worst is to let your stove set with the rain cap of the stove when it is not running. ASH+H2O=corrosive as heck. stainless mild steel boiler plate any thing (problee not) it will eat it up. there are some wood ash that is worse then others not for sure what but I think white oak is pretty bad with water.

Plus the black goo is very bad for the fire box also, it does "soak" in the steel of the box and makes it harder to absorbe the heat as well...

As for you you have a indoor stove what kinda stuff do you worrie about? what temps do you run it at?

is this off the topic?

 

[IndyIan]

As for you you have a indoor stove what kinda stuff do you worrie about? what temps do you run it at?

I find my stove burns well at 600-700F measured on the stove top. I assume it would be even more efficient if I ran it hotter but at some point it must take life out of the stove. At that temperature most of the actual flames are at the top of the fire box at the secondary air input tubes. Its pretty neat to watchopcorn:

 

[windthrown]

Don't cry for the Outdoor Wood Boilers...

Man oh man. If you have stainless OWB, rust in the firebox is not an issue at all. Even with a mild steel OWB like ours (Central Boiler), rust has not been an issue. On the water side there is corrosion inhibitor. No rust there. On the inside of the firebox there is no rust in our unit. I do not even use Ashtrol, which is supposed to keep the firebox ashes from rusting the steel out. Central Boiler uses really thick steel and even if it did rust some, it would take a long time to eat through the firebox. We have been up and running for over a year now, in a VERY wet climate (3 of the past 12 months have set records for rainfall, in an otherwise very wet climate). We do not have a stack cap and rain falls in there. I also burn a lot of damp and wet wood. I get pools of water on the door sill sometimes, and gooey creosote glommed on the inside of the firebox after burning some types of logs in it. But still no rust. I have looked up the corrosion factors on mild steel for creosote and it is very very mild. Even when wet it is below the threshold of being a problem.

I get more creosote from burning doug fir than anything else. I scrape it off with a garden hoe. I also stir the ash pan with a hoe every few days to keep any water or wet ash from collecting or sticking on the bottom of the pan. If the creosote builds up too much I burn a few cardboard boxes in there with some alder hardwood when the boiler is cool (say about 120 F). I let the fire jet right out of the stack. Cardboard burns hot. The creosote pillows up and burns off by itself. At the end of the year I clean out the firebox and burn the creosote off with a propane field burner. That dries it out and fluffs up any remaining creosote. Then I scrape that off and mist it with a thin coat of used motor oil and wipe it down. Then I cap the stack with a 5 gallon bucket flipped over, and spray the door hinges and latch with WD40. Then that's it for the summer.

If the power goes out, I would just crack the door open and let the unit burn off all the coals and wood in there. Then as soon as it cooled down I'd pop the bucket on the cap and leve it until the power came back on. Power failures are rare here though, and we have not had an outage for more than a few hours at a time. Rust is really not an issue for OWBs if you manage it. I know people with CBs that are 10 years older than ours and have no rust at all.

 

[MS-310]

The top of our F600 usually runs about 450F. I worry about people with OWB's when the power goes down for a week and the huge replacement cost OWB users face as their boilers turns to rust.

Condensate is very corrosive and tends to form in the corners in an OWB.

never seen a OWB rust from the inside out.... Im sure it has happened. but its from the water jacket to the fire box.

Hay if you lose power for that long drain the water and drain your pipes in the house.

 

[windthrown]

Corrosion inhibited

Why drain the water in the boiler? Most CB OWB owners drain and refill them only once every 3 years. Actually, if they are drained they would just corrode more. CB uses a corrosion inhibitor in the water to keep the pH and acid demand of the water such that ions flow from the water to the metal, and not from the metal to the water (causing it to rust through). No pump activity? Not a problem. So when the power is out, it does not matter. At least with a Central Boiler like ours.

We can also heat the house with the EPA fireplace while the power is out, but that takes a lot more firewood and the heat is not very distributed in the house that way. We would move into the living room and snuggle more I guess. Hmmm... now there is an idea... maybe I will have to run over the buried electric cable to the house with the tractor bucket accidentally jammed into the ground? :biggrinbounce2: