[Tom White]

I've chucked the bit of paper that came with my immersion heater away, and I'm not great with electrics.

I'm using a heavy duty extension cable and I'm looking at the timer I bought and it says suitable 13 Amps Resistive load and 2Amps inductive.  

Is this okay?

It also says min temp 0 Celsius, which is a pain, but I'll use it anyway; actually I could put it in the main supply in the shed; which hopefully won't go much below 0 Celsius.

[Lee GLS]

13 amps will be ok, because that is what the will be in the plug, but you need a timer that is rated at over 3kw, I had 2 at home, one rated at 2.2 and the other rated at 3.1.

[Tom White]

Yes, the timers are both rated 3 Kw, but the Amps thing confuddled me?