Thanks for the info Robert. Everything checked out fine. However I still get intermittent use out of the furnace. This morning I noticed that the circuit board had a burnt spot below the white thermostat wire connection. It appears that a resistor failed. So I ordered a new circuit board. I hope thi...

Hi Robert, It is happening again! The three flashes are back! Robert, how do I hook up my voltage meter to check for the voltage on the pressure switch? If I remove the cables the furnace won't run. Also how much voltage is there suppose to be at the gas valve? I am getting 15 volts ac. Is this corr...

A few weeks ago my furnace was operating intermittently. I check it and found the pressure switch was causing the problem(three flashes). So I ordered a replacement from your company. It arrived promptly(thanks). Today I decided to replace the switch. After the installation the problem remains, thre...