The TimeGuard Economy 7 Programmer (located in the store cupboard) controls the heating of the stored water in the PulsaCoil Hotwater Cylinder using off peak electricity. 

For it to operate the fused switch on the wall has to be on.  Do not get this switch confused with the Ventilation switch.  If it has been switched off, then all the settings will have to be checked. 

The Economy 7 off-peak electricity period for E.ON Next is –

Winter (GMT) 00:30am – 07:30am

Summer (BST) 01:30am – 08:30am