Is A Timer Needed Or Is Immersion Heator Not Configured Correctly With Off Peak Rate?

Hi

This is following on from the last question with regards to whether or not i need a timer installed. I purchased a flat 9 months ago and it has a Gledhill Pulsa Coil Class A Immersion heator. On the wall above the heator is two switches, one labelled "water heator" with a red light that is always one, i'm assuming this is the normal peak switch. The other switch is labelled "Off Peak" and i also have this switched on at all times though i've never seen the light come on for this.

I've checked with EON and they have confirmed that i'm on Economy 10. What i'm finding after taking a shower in the morning though is that when i check the immerssion heator afterwards, the red light is flashing rapidily so i'm assuming that the heator is heating up water straight away rather than waiting until the off peak hours kick in.

I tend to find that if the water runs cold during a shower of a morning or during the day, the heator normally takes two hours to heat up the water during the day before i can get hot water again so i'm wondering how i can get the immersion heator to only heat up water during the off peak hours and reduce my electricity bill.

I wondered whether i would need a timer installed or if its a case of one not being needed as i already have an off peak switch installed already but perhaps the immersion heator isn't configured to heat up during off peak hours only.

Sorry if this seems a stupid question to ask, i'm pretty clueless when it comes to things like this. Any advice given would be much appreciated.

If you are on E10
7 hours at night and 3 during the day
Leave the off peak on and should work all on its own.
The peak one although on should not work until the boost ( black button ) is pressed.
You could have other troubles.

Thanks a lot for the info mike.