I have a Goodman Janitrol gas FHA furnace which has been shutting down due to the pressure control switch line fills with condensate. The furnace is vented to the outside and is about 15-20 yrs. Old. Any ideas as to what the problem may be and how to correct it?

The condensate drain hoses and/or trap may be clogged, preventing proper drainage and flooding the switch. Additionally, the pressure switch may need to be moved from the factory-installed location to "higher ground" to eliminate condensate migration.