PRESSURE SWITCH INQUIRY

Modine unit heater. Burner short cycling. I check my pressure switch that closes at .91", and get an approx. .60 reading. Check flue, sure enough it is plugged up with a birds nest. Clean it out, and re-check pressure, I get above a 1" reading. But when burner fires, the pressure drops to about .80. The pressure switch is definately bad, because even after cleaning the flue with a 1" reading, the switch wouldn't close. I have one on order, but I am concerned about the drop in pressure after the burner fires. Is this normal? Or may I have heat exchanger problems. I didn't see any visible cracks, but it was bright as hell in this room when I was checking it. It is a hot house for flowers. Thanks in advance.
Rich
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hey I'm guessin here but when the furnace fires, the exhaust is warmer than the disch. from the inducer. being warmer, the exhaust is lighter, causing less static? you said a flower shop, that translates into higher humidity than normal. humid heavy air thru the inducer vs furnace exhausted air thru the inducer.
you can still sell them a heat exchanger inspection ! http://www.visibledefects.com/online-store/scstore/index.html
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Anyone know if this stuff works on plumbers too?
Patent Pending Contractors Crack Finder. Price per case, four one-gallon jugs to the case. (Shipping not included)
Price: $ 284.00

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"Oscar_Lives" wrote:

dunno about plumbers but it is AWESOME when it comes to finding two legged cracks at the beach.

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This stuff works nicely on plumbers too. http://media.putfile.com/crack-spacklel
Bob
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