Propane tank pitting

[huffdawg]

Went and picked up two 500 gallon tanks and one 150 gal. tank. One of the 500 gal. tanks had a fair amount of pitting on the exterior . I was there last week and it was full of gas and had over 100 psi in it. Can the pitting be filled up by welding or would it be best to just leave it alone.

Also anyone know how big is too big for a buffer tank? I was thinking of using the 150 gal. tank as a buffer or primary loop .

Cheers

Huff

 

[ewdudley]

Went and picked up two 500 gallon tanks and one 150 gal. tank. One of the 500 gal. tanks had a fair amount of pitting on the exterior . I was there last week and it was full of gas and had over 100 psi in it. Can the pitting be filled up by welding or would it be best to just leave it alone.

Also anyone know how big is too big for a buffer tank? I was thinking of using the 150 gal. tank as a buffer or primary loop .

Cheers

Huff

Mine had some pits that I would wish they didn't have. But their depth is pretty easy to measure with a $20 digital caliper from HF or wherever. I couldn't find any deeper than 0.040" or so, and with over a quarter inch of steel to work with I felt a lot better about it. I filled the tanks completely with water and pumped up the pressure with old 90W axle grease in a grease gun to up over 120psi and tapped the worst looking spots with a ball peen and they felt quite sound.

My buffer tank has a tankless coil suspended in the top for DHW so I can pump water to the buffer tank in batches and have the heat located close to the heating loads and the DHW piping. This way I don't pump hot water from storage over for heat and/or DHW in dribs and drabs and lose heat keeping the pipes between storage and load hot all the time, especially in summer. Also the buffer lets you insure that the heating water is fully depleted of heat before returning to storage.

I used a 30 gallon tank but would have used a 100 gallon tank or larger if I had had room for it, bigger the better I would think, at least until it takes up too much space or is too difficult to insulate or whatever. If you could swing it, it would be slick to have a short fat buffer tank that could feed a DHW tank sitting above it by gravity through a heat exchanger.

--ewd

 

[in hot water]

The old gravity heating systems worked by using generously sized pipes to leverage the buoyancy of hot water rising. I'm not sure how well gravity would work with long coils of copper. I know some DHW re systems, but not all, work with gravity/ thermosiphon. It seems to be a hard concept to predict HX exchange in.
Nothing wrong with trying, a small circ could always be added.

hr

 

[woodsmaster]

One of my tanks had some pitting but I didn't do any thing with It. My exp tank had the worst pitting of all my tanks, so I'm not going to worry unless it starts leaking. You could weld a patch
over the pitting ,but I wouldn't try to fill the pits with weld.

 

[DaveBP]

If any areas seem thinner than the rest you can always drill a small hole through there and see how thick the metal is there.

Don't forget to weld it shut before filling.