Agree with above, confirm with a VOM before ordering or swapping out a heating element as they rarely fail.
I worked on one a few years back that was tripping the 110VAC circuit breaker repeatedly for the guy and upon investigation I found that the hose going to the surge tank was leaking and dripping directly on the connection at the electric element causing an external short. Turned out to be a quick and easy repair. After I had it repaired and gave him the news he said "oh yeah, I have been having to add glycol about once a week".
It would have been nice to know that when he dropped it off.
Mike