Buying a used OWB

[PurdueJoe]

I'm getting ready to look at a used (3-4 year old) OWB made by Central Boiler. Before I buy what should I look for as possible deal breakers? What's considered normal wear and tear vs. a POS.

 

[oneoldbanjo]

I have a Woodmaster 4400 that has just gone through it's 3rd burning season and I take care of it by washing it at the end of the burning season, cleaning out the ashes and scraping out the stuff clinging to the inside, hosing down the inside with some motor oil thinned with diesel fuel out of a pump sprayer, then I wipe down all the exposed metal door parts with a light coat of motor oil. Before I do all this work I drain the system and add new water and conditioner and run it through one more heat cycle and let the pumps run for a few days to curculate the new fluid and disperse the treatment.

After 3 years my furnace does not have any rust or pitting in the firebox, the outside has just a bit of staining from the smoke that exits while loading wood, and there is no rusting of the exterior door, legs or metal siding. The metal screws that hold the siding on are corroded and a bit rusty. On my furnace you can see the inside of the water jacket by using a ladder and looking down the vent, and the metal on mine has a somewhat yellow/orange appearance - but there is no visible rust or scale.

My neighbor is not nearly as good at maintenance and last year when I helped them get their furnace going I saw that their firebox is pitted. They burn much later in the spring than I do and I believe they sometimes let the fire go out and don't cap the stack......so the spring rains dump water into the OWB occasionally.

I would say you should look to see if there is any corrosion or pitting in the firebox and/or water jacket if you can look down a vent. I might also suggest that you open the drain and see what comes out with the water. You don't want to see rusty water or scale coming out of the drain. If you decide to buy it I would suggest that you get it fired up and make sure it operates, then shovel out the coals and ashes and drain the water out of the system while it is still hot and open up the vents and uncap any of the openings to the water jacket. This will allow the water inside to evaporate as quickly as possible and help eliminate any additional rusting. It would be great if you could get some air flow using a small fan, blow drier, etc. to help get the moisture out.....if the unit is stainless......never mind on drying out the water jacket.

 

[i'mstihlaguy]

Maybe I missed it by why dry the inside of the water jacket? Are you assuming he won't be installing it till fall?

 

[gwiley]

As a rule the inside of the water jacket should stay submerged, this limits the exposure of the metal to oxygen and reduces rust. Central Boiler recommends leaving the water IN the furnace between seasons (had a discussion with my dealer about this very thing).

 

[oneoldbanjo]

Maybe I missed it by why dry the inside of the water jacket? Are you assuming he won't be installing it till fall?

I was assuming that he would have to take the time to dismantle the connections, load it, haul it home, get his place set up for a the furnace, bury lines, etc. It could be days, weeks or months before it had water and treatment put back in. If the inside is not dried out I suspect rust would start to form pretty quickly.

 

[mtfallsmikey]

If they used CB water treatment, any water coming out of it will be yellowish in color, unless there's iron in the makeup water