my furnace's light sequence is on and off it says no problem then switches to check polarity?

Question

when the furnace is making combustion with natural gas, the light is constantly on, and when it stops it it blinks continuously, until combustion. How do I check polarity? It's a Jantriol

Answer 1

Who ever installed it should have had the correct polarity. One way to check the polarity would be to get into the junction box, locate the black wire comeing into it, take a meter set above the incoming line voltage and set to AC voltage. Touch one lead to the black wire the other to a paint free surface on the furnace if it read 110 or there abouts then you are connected properly and the polarity would be fine. Also make sure the black is connected to the black and the white to the white.