I have a MUA ENG A unit that has JMC-2 Heat Controller, when the unit calls for heat the heat controller goes in PP Problem. The red LED light blinks constantly on PP Problem but the burner blower is running. (Goes in Prepurge cycle) the blower has a sensor speed control burner close to the shaft. I adjusted close to the magnetic ring but it doesn't do anything. Does anyone know how to test the sensor or the controller to fix this problem? Where can I find the diagrams and information about this controller, I went to different websites with no luck. PLEASE HELP ME OUT!!!!!