Goodman Furnace - 3 Blinking lights, solid light w/suction on hose to pressure switch
Hello,
I have 3 blinking lights on a Goodman GMNT080-4B gas furnace. An online manual says this is caused by "PRESSURE SWITCH FAILURE TO CLOSE" and to check: "VENTER, PRESSURE SWITCH, VENT BLOCKAGE".
One potentially useful bit of diagnostic information is that if I suck on the hose going into the pressure switch, the status light turns solid red: "NORMAL OPERATION". It returns to three blinking light immediately after I quit applying suction.
My assumption is that the blower assembly is not producing enough suction to pull the switch closed. Is there an easy way to determine of the problem is the switch or the blower motor?
Any other advice greatly appreciated and nothing is too basic. This is my first foray into the working of the furnace.
Thank you.
Lewis