Dick,
I cannot think of any, there are a couple of 120V temperature sensing button type contactor devices in series with the heating element that are run straight from the 120V breaker. The burner is all a 12V system. One button thermostat kicks the element on and off at temperature and the other opens if the unit reaches an over-temp condition. There are some small plates near the burner on the boiler face where you get access by removing the plates. There is probably an equal chance this is a button thermostat or wire fail as there is that it is a bad heating element. The manual that can be downloaded shows these part locations and some trouble shooting in the breakdown.
The button thermostats are not hard to change, the element could be difficult plus you have to drain the boiler down to below the element. You could see if you have 120V across the heating element with the boiler at less than roughly 170 degrees. If no voltage it is one of the button devices or a wire. If voltage is present and there is no current change, of about 10 amps, on one of the legs of your monitor panel with the breaker being switched on and off then it is an open heating element. You can confirm that with a resistance measurement when you remove the wires from the element. Hope this helps.
Later Ed
