Ecomony 7 hot water immersion not working

[ShazDorm]

Hi, I have a big old water tank that is heated by electric immersion. I am also on ecomony 7 (cheaper electric at night rate). So a few days ago hot tap water started running cold and not heating tank at night. There is a day switch in im bedroom (marked day immersion) which i've turned to on and have had hot water since but I have a few questions:
Guessing the probelm is the thermostat or element for the night heating, or maybe the electrics to that thermostat but any advice would be great thank you
If I cant afford to get someone to fix it is it ok just to just use the day switch to heat the water from now on? will this harm the tank? cost me loads more money? if so could I just switch it on an hour before hot water needed to save money?

 

[jam1979]

i take it your day 1 is at the top of ur tank and ur night 1 is at the bottom if it ur bottom 1 that has gone the 1 at the top will only heat that top part of ur cylinder so u wont get that much hot water u will need to get a plumber in to change it unless ur confident to do it ur self it might well just be ur thermostat to that 1 that is nackered u need to check with a multi meter that there is power to it if not theres ur problem

 

[Crinkmeister]

Could be your Economy 7 timeswitch at fault - I have had these fail before. You could check by looking at your electric meter after 11pm or whenever your cheap rate starts.