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[SkeeterMark]

Hello everyone. Newb here, but have been using an OWB for 4 years. It's some type of old brand, and came with the property and I've learned about it's use along the way.

I don't know what brand it is, and I have not found any markings that indicate what it is. I've searched the internet and here trying to find a description or image with no luck. It is not homemade. It is cylindrical, with white insulation almost like plaster on the exterior surfaces, except the front. The heat chamber is round, and the stack goes out the rear, and through the water jacket, exiting back out the front before turning upward. Fan box is on the front as well. Anyone know what kind it is?

Also, and the real reason I came on here, is I'm getting very little heat out of the system this year. It has worked great for 3 previous winters but is barely keep the house above 60 this year.
I've purged the system of air several times, as this is sometimes an issue in Fall when I first start it up. I don't believe air in the loop is the issue.

I had to replace the pump this fall as the previous one (only 1 season old - Taco) had quit. It had quite a bit of rust stain on the impeller. I have no problem with keeping the water at temp at the boiler, and it's hot (reading with temp gauge on outside of fittings, and using touch) through the heat exchanger for the hot water heater, and up to the water to air heat exchanger in the furnace. Coming out of the furnace, not so much. In fact it's pretty much air temperature if the furnace fan is running, which is nearly constant at this point. If I turn the furnace fan off, everything heats up for the full loop, so some water is circulating through. My gut feel is that the heat exchanger with its restrictive size is clogged or obstructed with scale or other debris.

This Fall was the first year I treated the water, or used softened water as I was ignorant to this previously. I think there may be quite a lot of corrosion in the system.

I am thinking to clean it all out this spring. So....

What is the best way to drain/flush the boiler?
Is the heat exchanger cleanable? I assume it would need to be removed. Do you concur that this is the issue based on the above symptoms?

Thanks in advance, and sorry if these questions are answered here already. I tried to search but did not come up with anything to match this scenario.

Edit: Got a chance to take a picture.

[cantoo]

Tough to ID unit without at least a picture?
 If possible I would pull your supply line off before the exchanger and see if you are getting flow. You might be able to check the exchanger then too.

[allis48]

Is your pump the same size as you took off? Either your exchanger is clogged or your flow is to low from pump. Is what it sounds like to me

[Scott7m]

Pump sounds possibly to small

If you wanna flush ur stove pouring 20 gallons of vinegar in it and circulating it for a day or two should help remove scale and build up in the system

Kinda redneck I know,  but it seems to work

[Sprinter]

Actually not redneck at all, vinegar works pretty darn good. It just doesn't work as fast as off the shelf brand chemicals. It's much safer too.

I'm guessing the flat plate needs cleaning, since he said it worked before, unless he replaced with a smaller circ.

[mlappin]

Check here, they seem to have a solution available for about anything.

http://www.woodboilersolutions.com/plan_open.cfm

[AirForcePOL]

I have thought about cleaning my current system out with vinegar before I hook up my new boiler this summer.  I don't really know if the system is dirty or not but I have a feeling there is some build up in the heat exchangers and such.  I am not worried about the pex because I will be replacing that but I would like to make sure that the HX's are free of debris before I hook them up to my new system.  Does anyone know if vinegar is corrosive to stainless steel?  And at what ratio should it be added?  How long do you leave it in the stove before you drain the water? 

[SkeeterMark]

Added the pic to help ID the unit. Also, yes, the pump was replaced with the same model as the previous one. I'll give the vinegar a shot. Thanks for the replies.

[fryedaddy]

Your sure that's not a homemade unit?

Nothing wrong with it if it is but I've never seen anything like that.

Th only thing I've seen close would be an aquathem without the jacket but don't think it's that at all.

[AirForcePOL]

Your sure that's not a homemade unit?

That's what I was wondering too. 

[cantoo]

I'm also thinking homemade unit or maybe a commercial one that has been modified? Maybe they started with a factory built indoor unit and added some "refinements" to make it an outdoor one?

[SkeeterMark]

It's not homemade, or at least not a one-off. I've seen another one (though not operational) in a field not too far from me. Also, I stopped at an OWB retailer to get a new rope seal for the door a couple years back, and he knew what it was. I can't remember what he said, though. He referred to it as an "old white elephant" and knew how the stack came back through the water jacket and stuff, so he seemed familiar with it. Maybe it's a local builder who made a few or something back in the day. I may have to go see him again or give him a call. Except for my circulation problem I have now, the thing works great. It services my hot water, garage and 3k sq/ft home, and I load it every 24-48 hrs, depending on how cold it is.

[SkeeterMark]

Ok, I am going to tackle the heat exchanger cleaning this weekend. Since I have to disconnect the plumbing, would it be wise to section the HX off for future use while I'm at it?
Everything is hard plumbed right now, but I'm thinking of putting in some valves for a bypass and some disconnects so I could do this in the future if needed, or replace the HX if needed more easily.
Is it common practice to make the components such as HX's more easily removed? Or are they usually not an issue so the extra parts are just seen as extra expense?

[slimjim]

Yes, valves and purge ports on all 4 ports will enable you to clean it by pumping acid through it without contaminating the rest of the system.

[AirForcePOL]

hey Slim, what is the best method of cleaning a HX with acid?  What type of acid should be used?