Have 2 high efficiency furnaces purchased from Service experts 5 years ago. One furnace was not heating, pilot light out and had and error code, and it turned out that it was a faulty pressure switch. Evaristo, the technician, did a fabulous job trouble shooting the problem, and found faulty humidifier valve issues, explaining why no humidity was reaching the one fuctioning furnace, obviously the one not working wouldn't have been able to gain humidity. I have had this techinican a few times and have requested him from now on. He's smart, thorough, not afraid to take the time to look into the problem and was diligent enough to take the time to look at my service agreement to see how to make this cost effective. Excellent work!