Can anyone help with this please?

I have the above, all has been working ok but it has started to not heat the water properly, it goes warm a few seconds after you put the tap on, but the it goes cool again.
Ive vacc'ed it out and checked all the connections etc but cannot see anything obvious.
Need to fix it ourselves if possible as don't really have the money for a professional to do.

Many thanks for any advice.

Mark, January 2009

For anyone else with similar issues, it turned out to be our gas supply. The regulator on top of the gas meter had stuck and was only allowing 7millibars instead of 19-23 which is normal. Called Transco off our gas bill (emergency) and they came out after 2 hours and fixed it for free :)

Mark, January 2009

Bit more info for you, when the hot water tap is turned on, then the flames start to kick in, they seem just as fierce as when the heaer worked, hope this helps.

mark, January 2009