paul asked ... Hook timing Janome QC 6260?    |    David asked ... Beeper bust?    |    Tom asked ... Service manual for Lawnflite 908LA?    |    John asked ... Scantronics 9450 box stuck shut?    |    Pekaye asked ... Clutch Cable change?    |    Click here to ask your question

How can I isolate air pressure switch?

I have an Economy 50F boiler which will not fire. I think it may be the air pressure switch but in order to isolate the switch I need to know which two wires to pair. There are three wires red, yellow and black which come from the switch to the board.
Dave, January 2009
Don't, use a multimeter to determine if the switch is switching or not. You should have 240v at the normally open connector when the fan runs.

Iain, January 2009
link Click here to see other fixes for Economy 50F.