troy

I have an older hot springs classic. The hi-limit switch keeps tripping out the heater and the red light keeps blinking. There are 2 pumps in the access panel. The large pump and a smaller one that looks like it is for the heater. When the main jet pump is running everything is fine. Once i shut it off, it seems only minutes until the hi limit trips out. Is there a way to check the smaller pump to see if it is running? Would that be the cause of this problem? Thanks Troy