Can anyone help me identify this?

Stemmer_2

Would love your comments. After almost 40 years in the heating business, this is a first for me. What is the yellow stuff?

bob young

old yallar

looks like boiler water treatment chemical. they used it in apt. house boilers . pacific tube steam

loose cannon

Heat -ex

It looks like a heat exchanger for a Lochinvar Powerfin or perhaps a RBI Futera II. Either way it's been condensing badly, and the build-up is from the by-products of flue gas condensation and possibly some system water to boot. There is so much build-up on it now that it may also indicate a leak in one of the copper tubes. The acidic products of flue gas condensation can eat through the tubes of a copper fin boiler pretty fast, so I guess the real question is did the heat-x leak because it condensed, or did it condense because it leaked?
Does the boiler have a bypass? Is it geting return water below 135F? Does the system reset on outdoor temp? Most copper fin boiler manufactures require bypasses. this may indicate a system problem. Hope this helps.

loose cannon

Heat -ex

It looks like a heat exchanger for a Lochinvar Powerfin or perhaps a RBI Futera II. Either way it's been condensing badly, and the build-up is from the by-products of flue gas condensation and possibly some system water to boot. There is so much build-up on it now that it may also indicate a leak in one of the copper tubes. The acidic products of flue gas condensation can eat through the tubes of a copper fin boiler pretty fast, so I guess the real question is did the heat-x leak because it condensed, or did it condense because it leaked?
Does the boiler have a bypass? Is it geting return water below 135F? Does the system reset on outdoor temp? Most copper fin boiler manufactures require bypasses. this may indicate a system problem. Hope this helps.

Stemmer_2

Thanks for the suggestions. I wondered if was chemical treatment. Your close on the product but pick a third.
I assume that for whatever reason, the heat exchanger leaked and that this goo is from the heating medium mixing with the flue gases. You would think someone stuck an oil burner in it.

loose cannon

At one time I worked with quite a few copper boilers but I've never really seen anything quite like that. A chemical additive would be my best guess also on what is causing the big deposits in the tubes. If it was just condensing it would be green and rusty. Unless the unit was getting some contaminated combustion air. It isn't heating a pool is it? Any chance it's getting a whiff of chlorine?
Changing out that mess must have made for a long day!
So what is that unit... a Thermefic?

John_86

Old Yallar

This is a heat exchanger that appears to have operated at water temperatures below the dew point. The bright green is a copper oxide where the condensing products of combustion attacked the copper tubes. The reddish orange is iron oxide where the iron of the V baffles is being oxidized from gas condensate. The yellow residue appears to be residue from the evaporated water as it is colored by the minerals present in the flue gas and condensate residue.

I would recommend a through cleaning with an acid coil cleaner as used in an air conditioning condensing coil. Remove the V baffles, spray the cleaner on the heat exchanger and allow it to set. Flush with a high pressure cleaner to remove the residue and fully dilute any acid present. Repeat as needed to fully clean the heat exchanger. Inspect the inner chamber and flue collector for breeching. Any holes must be repaired. Carefully inspect the red insulex coating on all the interior jacket surfaces. Any peeling or bracks in the coating should be repaired. Install new V baffles.

When a unit has reached this point in operation repair costs must be weighted in comparison to the cost of a new unit.

Kal Row

sulfer: yellow as solid, vry-dk-blu as lquid, brn as gas