The hot water is back. It seems that the “immersion” heater was wired improperly and lacked a rather essential fuse. The effing thing never ever worked before!!! And nobody – not the landlord, not his agent, certainly not the repair guys – knew about it.
Anyway, the slightly harassed repairmen made their third visit to our house in as many days – this time with a clear directive not to leave until they are sure that there is hot water in the house. They spend a good hour re-wiring the immersion heater, but they accomplished the objective splendidly.
Now we are waiting for the official date and time of the main heater repairs.