Ducane package unit with gas furnace. Led flashes 3 times which indicates pressure switch stuck closed or open. I unhooked tubing and blew air into it, seems to be working OK, also I disconnected wiring and re-attached. This is the honeywell switch mounted on left side wall of compartment. I cycled unit several times but it kicks out after running about 1 minute. Led flashes immediately 3 times which leads me to believe there is a manual reset button somewhere but I'm not sure where it is. Please help ! Gas co. Service man was here on Sunday had it running several hours after he left but it tripped again. I think the pressure switch is defective and I have another service call in but I would sure like to be able to troubleshoot things myself like the old days. Thanks

Service tech was just here (thur 12/17). Turns out the pressure switch is OK despite the led 3 flashes code, but the limit switch was tripped. Service tech reset limit switch as that has a manual reset button (little red button between the 2 wire terminals on the switch which is located in upper right corner of service compartment. The limit switch had tripped due to improper air flow in vent duct causing back-up in heat chamber and subsequent overheat condition. Primary cause of air restriction in flex duct was water getting into duct from flooding condition in crawl space. The package unit was installed in January 2006 but contractor was limited to where he could run the air return flex duct. Flooding problem was initially noticed this time last year. A sump pump was installed in crawl space and worked fine up to 2 weeks ago. We had substantial rainfall which flooded crawl space and sump discharge line got clogged with sand. Heating contractor cleaned out sump pump and he's working on trying to raise the ductwork a few inches so it does not sit in water every time it rains. We are located at the jersey shore (cape may county) and the water table is quite high. Flooding is a continual problem. Thanks for this web-site. Reading similar threads and other's related problems helped me immensely. Look forward to any feedback you can provide. Paulee5

Could you please put the picture up for the manual reset button!
Irina