economy 7 innersion heater

[mredhead]

Hello My boiler has decided to not heat water I think the ignition spark has gone as boiler sounds as if its working but flame is not there now.
I have an immersion heater in airing cupboard and never used it can any one advice what I need to do I do not have any information on setting it.
It is called Horstmann Maxistore ecconomy 7 heater it was put in house in dec 1991

Thanks from

Melody

 

[mredhead]

I have found a leaflet for installation but it doesn't tell me how to set it

It is a Horstmann model 425 tome control

Melody