We just bought a home. I bought a new 55 gallon, 240V water heater because the old one was disgusting as far as rust in the bottom and making the water nasty. I also re-wired the new one to the breaker with new 10 gauge wiring and replaced the 30 amp breaker as well. The top element tests at 249V (by touching the probes to the points on the element), but the bottom tests at only 120V (not sure if this is the source of my problem). I’m not sure how to run any further tests. The problem is it takes the tank like 15+ hrs to heat up once it’s used. Any suggestions?