Customer not getting heat when calling for it at thermostat, getting fan motor coming on in response to a tripped safety in system. After looking at system I found that the pressure switch was stuck open, after knocking it and shaking it loose the system began firing up and heating normally. System was not calling for heating when I called for it at the thermostat, i rewired thermostat to fit conventional furnace and changed setting in thermostat to conform to conventional furnace settings. System now heating and operational at 110 degrees, tested a couple times to ensure. Serviced customer on Magnolia Rd in Marysville, CA