DUNBAR
Have to use a electrical tester. Both thermostats will not burn at the same time, but in sequence.
On a cold tank, the upper will fire first, check that one first, then the lower will kick on.
After the tank has been operating after one cycle, the lower will always kick on first, then the upper to maintain the ready to use hot water.
“Your best interest is secured by making the right decisions the first time.”
