I have a faulty immersion heater in a new apartment. The 'top up / sink' option heats water for an hour or two but when I use the 'bath' option for several hours over night there is no hot water in the mornings. Would you think this points to a thermostat or element problem?
Assuming it is an element problem, are these expensive? I have little plumbing experience, would it be best to get a plumber to replace this?