I have a weatherking furnace. The furnace intermittantly will not start at night when it's very cold. The control board is flashing four lights which is saying the pressure switch is stuck closed. I recently installed a new pressure switch and hoses so I know they are not clogged. I checked and the switch is actually open but the control board still says it's closed. I also have a new control board so I don't think it's bad. I know the pressure switch is wired through a control transformer and a little black box (pressure switch delay timer). If I wiggle the wires on these it will usually fire up after I reset it and run for a week or two. Is it possible one of these are bad and how can I test them to know for sure? Why would this only happen when it is very cold at night? I know they don't cost much to replace but I don't want to be throwing money away.