I am working on a Carrier furnace. The code blinks 13. I changed out the parts pressure switch, reset switchs, main board. But it still will not get the HSI to click on. The vent fan goes thru it's 90 seconds and pauses and the blower fan will come on. But there is no signal to the HSI.
What else can it be.
Which model # is it? Mid or high efficiency? There should be a spill switch on the box where the smokepipe/venting attaches on a mid with a manual reset button located on the right side underneath it. On a high efficiency they should be on the sides of the burner box. Look carefully for them. Code 13 is open limit.
"Cut it twice and it is still too short".