[CAUSA]

Is this a ECO tripping?

Chances are the dip tube is cracked or broken and cold water is bypassed and the units is over heating where the limit is.

if the unit was over pressure or temperature in a unsafe condition the TPSV will open.

If a old tank scale build up can cause this as well but rarely. Usually the efficiency is noticeably reduced.

 

[CAUSA]

by ECO do you mean brand?
he said newly installed new tank was doing the same as the old tank
then the ho changed tstat
then called him
i suspect he solved the fuse blowing when he replaced the disconnect

ECO=energy cut off switch, always the very top one on tanks. 190F is the set point. on electric or gas models.

the lower hi limit is a little lower but that depends on manufacture and size of tank.