white and brownish mess

HP80

I'm not sure but could it be over-sized venting causing condensing of flue gases in turn reacting with the galvinized coating on the metal?

Paul Mitchell

That mess

you see coming down the flue pipe on oil systems mostly when they are attached to metal vent chimneys,at least most of the ones i see. sometimes it is white sometimes it is brown. big discussion today with the boys on what the problem is....what do u guys think?

paul

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Al Letellier

chimney mess

Paul, it's most likely residue from the condenstion of flue gasses in the vent....most likely sulfur based unburned by-product of fuel combustion. If you're getting heavy accumulations of this deposit, make sure and check the boiler carefully for corrosion and make sure you keep the boiler temp at or above the manufacturer's recommended low limit to protect warranty and boiler life span.

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Paul Mitchell

thanks Al

this happened to be on furnaces. did combustion tests. furnace was fine and bock hwh was just a little lean. also two lennox oil furnaces had the same debris. this i think was water coming down the chimney and mixing with the galvanized. you think its just products of combustion? what can be done about it.

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Paul Mitchell

HP80

one of my thoughts also. but it seems not possible. today the stack temps were at 500 or so. two units in one chimney also

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HP80

I still say your chimney is oversized. Try a power venter from Field and downsize your venting. (I think it is Field that has the oil approved unit). But as far as 500F stack temperature what size and temperature is your chimney/flue?