new owb!!

[owbpro]

heiss heaters

i have just went to the location of these heiss heaters and didnt think i would be impressed, but suprisingly i am. They have apparently upgraded almost everything about the units. I have a friend that has gotten a heiss heater and he loves it. i was not too impressed with the exterior but like tex said they are small things that can be changed. but i guess they now have new doors, they offer an exterior on the units [and my friend actually does get snow built up on the top] but the insulated unit is the route i would go. The now have 1" coming out of the units, and they now have steel lining the door. It appears as though almost all of their faults are now perfected. The water jacket on the inside does have about 200 ft or more in them. i seen the insides and it is just genius the way mr. heiss has come up with the manifold system on the inside. He also informed me that there is a check valve on the pumps he uses so there would be no back flow if your power turned off. He happily answered all the questions i have. I had to sign a waiver saying that i wouldnt tell of anything i seen while i was in there and i thought that was pretty professional. They now are patent pending. He informed me that they had just recieved their notification in the mail from the US patent agency. I for one am hard to impress especially when it comes to the outdoor wood boiler industry and i think it is just genius. The only thing i would change about it is the aquastat like tex.

 

[owbpro]

Generally speaking concrete is very alkili. It's why rebar in concrete doesn't corrode, the high pH allows for passivation.

Also copper would not corrode in this situation because it is not being oxidized. There is no water directly touching the copper and concrete at the same time. It is just like in-floor heating but backwards. My great grandfather's father built his house that he passed through the generations and he has copper in the in-floor heating. that house was built back over 100 yrs ago. Theres no problems with copper corroding in concrete.

 

[Biker Dude]

Why not use 1" pex instead of any kind of metal tubing? If you made the boiler cylindrical then you could wrap 1 continuous piece around it and be good to go, right? Even better would be a concrete cylinder wrapped with pex and then sprayed with flexible expanding foam. That would solve any unequal expansion issues and insulate the firebox at the same time. It would still be cheaper than traditional construction and transfer heat as well as if the tube was in the concrete. Hell, you could use small concrete culvert for the firebox and build one in your backyard without any special forms or pouring at all. I may have to try this...

 

[tex]

Why not use 1" pex instead of any kind of metal tubing? If you made the boiler cylindrical then you could wrap 1 continuous piece around it and be good to go, right? Even better would be a concrete cylinder wrapped with pex and then sprayed with flexible expanding foam. That would solve any unequal expansion issues and insulate the firebox at the same time. It would still be cheaper than traditional construction and transfer heat as well as if the tube was in the concrete. Hell, you could use small concrete culvert for the firebox and build one in your backyard without any special forms or pouring at all. I may have to try this...

Have you ever seen how much pex espands/contracts with heat?

 

[Pulp Friction]

......This is all very good info from everyone. If I was going to build a similar unit, what do you guys think about wrapping the copper first before the concrete is poured. Something like heat shrink tube would add a layer of protection between the copper and "crete", and allow for expansion/contraction. Just a thought.

I think that wrapping the pipes would insert a thermal barrier that would decrease the effectiveness of the heat transfer. Also, after several expansion/contraction cycles of the copper pipes, the copper/cement bond may be broken, however minutely, thus decreasing the thermal conductivity.

Does the Mfgr. spec out the weight of the unit? With that much mass I am inclined to think that quite a long fire-time is required to start getting the water up to temperature. 1 Btu can be stored in water for every degree F that each pound of water is raised, but what about the thermal mass of that much concrete? If I were to put that many Btu's into heating up that much concrete, I'd make certain it was captured with exterior insulation. I have my reservations about a unit like this, but it may be better served if it's cement structure was used more as storage mass and protruded the building somehow, not requiring water passages for transfer.

 

[tex]

Does the Mfgr. spec out the weight of the unit? With that much mass I am inclined to think that quite a long fire-time is required to start getting the water up to temperature. 1 Btu can be stored in water for every degree F that each pound of water is raised, but what about the thermal mass of that much concrete?

That is kinda the point of the unit. Just like a water jacket unit, the first burn will take a long time to heat everything up. After that though the concrete will retain all that heat, and only small fires will keep it hot.

 

[Biker Dude]

Have you ever seen how much pex espands/contracts with heat?

yeah, I use pex in my in-floor system and out to my OWB. That is why I suggested flexible expanding foam be sprayed over the pex, so it can be free to move around a bit.

 

[dahmower]

COuld you use a pipe inside of a pipe method with pex tubing inbetween the 2 pipes and the area filled with sand?? You would have to make sure the pex tubing isn't near the small pipe (burn chamber ) to prevent melting!!

 

[Biker Dude]

Yeah, that might work as long as you can pack the sand in enough so it doesn't all settle to the bottom. If you made little pex holders that fit between the 2 tubes you could just hang the pex in the dead air space with nothing surrounding it. Then it could move all it wants to but the heat transfer might not be as efficient. I suppose you could fill the cavity with oil and seal it off. That would help the heat transfer and the oil would be fine as long as air didn't get to it.

 

[mbeardsley]

heissheaters

BUMP!

I would be interested in hearing some of the experienced OWB users thoughts on these.

Thanks!

I bought one of these outdoor units several years ago and i cant tell you how happy i am with the unit. For the price and how young the company was i can see why the units were made a bit cheap. I have been keeping track of the company as it grows and now im a bit jealous of the units that they are producing. They are making the units now out of refractory cement which is a 3000 degree firebrick cement. They are now brazing the copper heatsink inside the refractory also. They now have insulated doors and they come with a digital aquastat and flow switch. The new units also are insulated with a hard extiorior. I love my unit and its done good for years now, I only go through around seven cord a year but may trade my old unit in for a new one. The company service has been fair and its been fun watching them grow. I guess they are offering gasifiers now which wont smoke.

 

[Elim]

I bought one of these outdoor units several years ago and i cant tell you how happy i am with the unit. For the price and how young the company was i can see why the units were made a bit cheap. I have been keeping track of the company as it grows and now im a bit jealous of the units that they are producing. They are making the units now out of refractory cement which is a 3000 degree firebrick cement. They are now brazing the copper heatsink inside the refractory also. They now have insulated doors and they come with a digital aquastat and flow switch. The new units also are insulated with a hard extiorior. I love my unit and its done good for years now, I only go through around seven cord a year but may trade my old unit in for a new one. The company service has been fair and its been fun watching them grow. I guess they are offering gasifiers now which wont smoke.

Thanks a bunch for the info. I will have to go check them out now that they have more experience under their belts. It sounds like they are learning from past experiences, and improving on the initial design. Glad to hear they are constantly developing their product. Thanks again! Rep sent!

 

[roger m]

interesting,i bought my owb 3 years ago and it has paid for itself this past winter,i couldn't imagine not having one now,mine heats my house and shop and i couldn't be happier with it:msp_smile:

 

[tex]

I've been kinda keeping an eye on them also, and I've heard some bad stuff about their "after sale" customer service. That's not to bash them, but just an FYI. Their prices keep going up too. They are getting in the ballpark of a good steel unit last I saw. I'll have to check out their site again. Its been awile.

 

[hawleybk]

lol where do i start ......................... I would never buy one again !!!!!!!!!! just my 2 cents