hi.ive just started servicing. newcomer to gas scene. could anyway one tell whats the purpose of flue baffles, and what causes the yellow deposits on iron heat exchangers?
The flue baffles increase the efficiency of the heat exchanger ie they increase the transfer of heat from combustion products to the heat exchanger surface. Google "boundary layer".
The baffles help create a more turbulant flow of flue gas to prevent a slow moving gas layer (that prevents high heat transfer) near the surface of the heat exchanger. With tubular heat exchangers (typical copper tube designs) it is also common to have baffles inside the tube (again for the same reason but usually known as turbulators).
The downside of baffles is that the narrowed flueways can clog and if servicing is infrequent can be a bug*er to remove.
The yellow deposits may be due to small amounts of sulphur in the gas but I may be completely wrong.
I think that this fellow is more likely to be refering to the "fins" on c.i. heat exchangers, Geoff.
If so their purpose is primarily to increase the surface area of HE in contact with the combustion gases.
Whilst I cannot confirm the chemical content, I dont think its anything do do with sulphur which would be quickly vapourised/burnt. I suspect its is something else.
This posting should ideally be in the CC where we can give unfettered advice on gas matters.
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