Plumbing Questions? Ask a Plumber and Get Answers ASAP.
How old is the heater? Have you ever had it descaled? This unit should be descaled every year or two. It is also possible that there is a problem with the wire to the controller. You can easily open the panel and check the wire harness and / or connection. This could be an issue with a bad connection. I would recommend a descale with cleaning the intake and exhaust vents. Also, have the plumber check the burner area for debris and clean the ignitor. Good Luck!