Washing Machine washing cold.

[Slooow_Jo]

My zanussi FJ1093 has started washing with cold water,I've tried to find infomation on the internet about what could be wrong as it is working fine otherwise, but I've been drawning blanks...any ideas?
This morning I noticed that the system pressure gauge on my central heating boiler is at 3 instead of 2.5, could this be causing the problem?

[tomtech]

where the hot pipe goes into the back of the machine should be a filter. turn off hot supply to machine, unscrew hot pipe, pull out filter and clean it. they often get clogged with limescale. if its not blocked then it must be an internal fault.