water running down walls in wood burning furnace

my employer has a wood cozeburn wood burner water runs down walls continually no matter how hot it is burning.the furnace is not loosing any water so we ruled out a leak. we did have a leak last year but that was fixed.any one have a reason for this

What's the temperature set point for the water? If it's not hot enough that can cause the problem. Also on the return side if it's to cool can do the same in some wood boilers. I normally run 170-on and 180-off. This past cold snap I went up to 180-on and 190-off.

the water temp is 125 this is the temp we have had it set on since I been there 8yrs.that is part of problem we are not doing anything different wood is well season

You're right on the borderline of condensing, which is whats happening. your return water is too cold, you do need to turn the temp up some.

If you have no leaks then your water temps are too cold. Central Boiler now requires the installation of a thermostatic valve in the lines that cuts off flow to the the heat exchanging units at (I think?) 180 degrees and returns the flow back to the boiler. For reasons unknown to me some designs are worse than others. I have operated a 4400 Woodmaster for 7 years and have never seen water condense in it when warming up, cooling down or operating BUT we also never burn green wood and our wood is stored under cover. I helped a neighbor install a Central Boiler last fall and was AMAZED at the water that pooled up in it when we fired it up. He hates that stupid valve, and so do I but if you by pass it your warranty is voided.

140F is the condensation point in wood boilers. You are running it WAY too cool.
Read earlier post on tool talk and TT
Loren, the Acg.

I run a Heatmaster SS and have played with the temp setting quite a bit trying to find a happy medium where it does not cycle my blower as much, yet does not burn a ton of wood maintaining a high water temp, and boil or steam off water. I have found that on mine approx 150 on, and 160 off seems to work well, although I do drop that by 10 degrees in warmer weather. I also learned the hard way to never burn green wood (although I do toss a few small sticks in one at a time if they get in the way, but normall I only cut dead wood. Other than that, this thing burns anything I toss into it including full bags of trash. When I bought my furnace I heard the stories of only filling it once a day, even one even less. I think those tales are just that, as I have never been able to only fill once a day unless it is a low temp around 45 or 50 degrees. Then again, I heat my residential water as well via two heat exchangers in series with the heat exchanger mounted inside my furnace (one side arm and one plate "pre heating" the incoming water to the gas water heater which is turned off. I am likely gettting off topic, but I'd turn the temp up to 150 or 160. I think it will eliminate the condensation, and be more efficient as well.

Yep to what all the others have said. Good advice.

If it's not colder than 20 degrees overnight, I have no problem firing mine once a day. Heating a large 2 story home, domestic hot water and my shop which is 40x30.
Yes his temp is too low, I change my temp settings according to the temp swings.

When I was researching which outdoor wood furnace to purchase I saw a lot of discussion on forums surrounding rust and corrosion issues due to condensation on Central Boiler (may just be certain models?). Rather than take a chance, I avoided and had a difficult time deciding between a Hardy, and the Heatmaster SS I purchased. So far I have not really regretted my decision, other than the guy I purchased from and his shoddy installation. Wish I would have known a little more on how simple they are to install, and I could have avoided about $1500 in cost - some of which was to hire my furnace/sheet metal guy to fix the mess and do it right where they heat exchanger was in my furnace ducting. I also had to end up adding a plate heat exchanger as his side arm exchanger would not do the job - he said I would have to leave my hot water heater running. Now I have all the hot water I need without running out, and can turn gas off while furnace is running.

I run my thermo-control wood boiler at 170f on 180f off seems to work well so I leave it alone....I messed with dif temps till I was happy and does not burn a ton of wood either...
Kelly

thanks to everyone for the information this info will help

thanks to everyone for the information this will be helpful

An OWB is in our future, I hope!, so a big thanks to all the participants in the discussion. Very interesting for those of us unfamiliar with the operation of OWBs.