I'm installing a new draft inducer (exhaust blower) that came with four limit switches that have four different colored dots (white, yellow, red & blue) on them. I have only two limit switches on my furnace, the upper limit switch is blue dotted and the lower is yellow dotted. Am I correct to use the new yellow dotted limit switch since I am only replacing my current yellow dotted lower limit switch?


It sounds like you got a "kit" that can be used on various units so I would say yes you should be fine in doing that though I'd probably do both limits but at least keep the ones that go w your unit as spares.

Updated on February 14, 2018

Original Article:

How to Figure Out What is Wrong With Your Furnace
By Dan Robbins