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[dirtdigger]

I've been looking at a new OWB and the subject of pressurized vs non pressurized boilers has been a discussion, I've been told many things about each, first off, I understand the whole concept of pressurized boiler being a pressure vessel, which doesn't really bother me any, I've been around pressurized boilers all my life, all the houses I've lived in the last 25 years have been hot water heat with cast iron radiators.     

My main question is this, how come the pressurized boilers I've been around most of my life, have had no rust out issues and were anywhere from new to over 30 years old, the older one's were fuel oil, and the newer one's were switched to LP gas and my wood doctor OWB has had rust issues in the first 5 years, is this a freak accident, poor quality steel, water issues, which is the same water as in my previous pressurized gas boilers or is there something to the idea of pressurized systems less oxidation issues.    My gas boiler people are telling me one thing, and the OWB sales people are telling something else.     

There are a couple pressurized OWB's on the market, I've talked to several who own each brand, and from what I can tell, the stainless steel construction has had issues with leaks.     

 

[slimjim]

WoW, that's a lot to chime in on, first it sounds like you have been talking to the same guys who used to build the unit you currently have, I sent you a PM with the blower model number you need and would prefer to have a conversation offline as to how I personally feel regarding Silver Winds, your issue could very well have been self induced but I doubt it

[dirtdigger]

No I haven't been talking to any of that bunch, I've been talking with legitimate business's and products they sell and hopefully stand behind, as they say Ive made a mistake the first time around, I'm trying to not repeat it.   

[slimjim]

The reason that I ask is that they have gone back into business with a pressurized unit and blame all their misfortune on a non pressurized unit, I for one do not like a pressurized outdoor wood boiler for the safety aspect alone!

[LittleJohn]

Pressurized units generally have less rust issues, becasue of a lack of oxygen in system.  I mean there is only so much oxygen in the system then you close it off; a little rust forms and most if not all the oxygen is gone or used up. 

With an open system, there is no lack of oxygen and that is where water treatments come into play.

...now there are other issues that may arrise with a pressurized unit, mostly related to safety issues/concerns since the unit is a pressure vessel; the inclusion of expansion tanks and pressure relief valves are the primary difference.

[dirtdigger]

The rust issues are my main concern and the reason I'd go pressurized in the first place, but do the claims of buying a pressurized unit, which are higher priced in most cases, stand up to that reason alone, they won't rust as fast or have as many issues.    The logic behind it is sound, those units have to have a pressure rating and fall into a whole different classification of furnace, meaning they have to undergo far stricter guide lines to build in the first place.     

That right there makes me wonder how those with the supposed certification can now sell pressurized boilers, from basically the same furnace they had before...............or did they get all the necessary paperwork and certification needed to legally sell anything....................hummmmmmmmmmmmm, I know, that's harsh to wonder how such upstanding individuals could do anything underhanded or illegal or what might fall into that grey area.     

Well anyhow back on topic of legitimate business's who do make a pressurized boiler and have the certification behind it along with decades of sales and many thousands of units.   Anyone want to venture a guess or have data to back up the life expectancy of a pressurized boiler verses a non pressurized one?    I've listened to the sales people, along with those that sell lp gas pressurized boilers and they all claim the same thing no matter who's unit it is, pressurized translates into higher quality and longer life built with better quality materials ....................or the nuts and bolts of the question, is it true?

[slimjim]

I'm not sure about higher quality, if you choose to go pressurized, be safe, period.

[MattyNH]

Pressurized outdoor boiler owner here.. Owning a pressurized boiler I don't have the worries as if i was to own a open outdoor boiler.. Pm me for questions..I have answers, experience...I don't need to hear the crap on this that may drive u away from owning a sealed boiler..

[slimjim]

What crap is that Matty?

[LittleJohn]

Another nice thing about pressurized systems, you can have radiant heat on a 2nd or 3rd floor (above your boiler)

...I once saw an install on a commercial level; at an Enviromental Learn Center, where they had a central "boiler house" that they swapped out 4 old open system wood boilers for 2 high efficiency pressurized pellet burners.  We are talking MILLIONS of BTUs/hr, across something like 8 or 9 structures, the pressure vessel for the system was ridiculous, I do not know how many gallons it was but it was something likw 8 ro 10 feet tall and just as wide.  **NOTE** They had multiple runs of what looked like 4" or maybe larger pipe, and pumps the size of small European cars

[slimjim]

I wonder how much of my tax dollar was pissed away on that project to promote pellets

[LittleJohn]

...oh don't worry SLIM; Will Steger was there saying how good it was for the environment to use pellets and what not. 

  Wait so I have to pay a guy to bring me wood pellets, and I can't cut down the dead tree along my driveway and burn it     Thats what I was trying to get away from was paying someone to heat my house