Yes the circulating pump is prime suspect... You should hear a "hummm" from the pump or unscrew the large "plastic/brass " screw cap on the front of the pump motor. (you might get a few drops of water) Insert a screwdriver to the slot and if the pump is running you will feel the vibration/noise. If not, switch off and try turning this screw. If/when it turns freely try switching on again if not then it is perhaps a faulty pump motor or circuit.
(often the circulating pump will stick if old or residu in the water)
jon, June 2008
