Hi sifus.

My tenanted unit meru 45l tank heater on switch totally no hot water. A year ago hose leaking spent 350 repaired now heating element failed need 380+100 to replace.

Decided to move to instant heater instead.
Noob questions:

1.Should water be let out from the tank since no longer in use in future?
2.How to empty an erected Meru tank with outlet hose on top and inlet hose at bottom? If you know any expert plumber in this please ask to DM me price.

The current switch is 2-way meaning 1 heater shared between 2 bathrooms. Developer cheap design. Managed to install 1 instant heater using the original heater wiring.

In 2nd bathroom, it is renovated with a 3 pin socket for shaver, hairdryer etc. The current heater switch is outside bathroom.

3.Can this socket be converted to instant heater switch? If it is not safe, does it means need to add wiring and drill a hole to reach the current switch outside bathroom? Tenant doesn't want too many holes n wiring casings, need fast job that do not inconvenience them. However, safety must come first.

Hope all great sifus can enlighten me. Thanks.

Definitely engaging professionals. Just trying to understand the problems as few plumbers and electricians gave different solutions so I get confused.