Rinnai Heater clicking sound

[akh44]

I moved into a condo earlier this year that has a gas direct vent Rinnai heater (Model RHFE-1001FA). Something doesn't seem quite right to me, but considering I've never had a Rinnai before, I wanted to see if I even have a problem before calling someone out to look at it.

It's working - the ignition light comes on and then the fan starts blowing out hot air. But after 6 seconds, I hear a loud click, and the fan stops. This happens every cycle, which will begin again anywhere from 30 seconds to 10 minutes later.

Is this clicking normal?

[HayZee518]

check the flamerod detector. it may have soot on it or is touching the flame ring or combustion pot