Harman XXV, combustion fan suddenly stops, then restarts

[millerpc99]

I have a Harman XXV that is nearly 3 years old. We recently have been having issues where the combustion fan suddenly stops and causes the flame to fade. It will almost always kick back on in a matter of seconds. It goes from doing this once every hour to every 30 seconds or so.

The technician said that he thought it was the circuit board. After spending $160 for the part and replacing it myself, the problem continues. The tech also mentioned that it could be the ESP Probe. My fear is that I spend the $ to replace the probe only to have the problem persist again.

Has anyone seen this before?

Any help is greatly appreciated.

Thanks

 

[Delta-T]

there aren't any good reasons for the combustion blower to shut down when there is a fire....should be the very last thing to shut off. Could be an ESP issue...but does the Distribution blower continue to run when the combustion blower shuts down? Does the light on the control board for the combustion blower stay illuminated when this happens? The only way to assure that its the ESP is to have a tech hook up the DDM (diagnostic thingy) and see what the ESP is telling the control board. Any chance the wires for the 2 blowers got switched? Odd line voltage can cause weird things to happen, but if you've had it for several years without issue that might be a stretch.