Boiler problems - hot water!

[lovestogarden]

We have a boiler (water and heating) and its having a bit of a strop at the moment. Sometimes we have no hot water - it can either be cold from when you turn the hot tap on (sometimes it gets hot) or go freezing in the middle of a shower!

You can get the hot to come on however by tapping/pressing on the front panel of the boiler on the bottom left hand side. There is no button or switch there - you are literally just pressing down the plastic!

Please tell me its something small, simple, east and cheap to fix!

Oh come on, there must be a tinkerer out there!

You should not tinker with the boiler.

Sounds like either a problem with the wiring to the thermostat or the temperature sensor. Shouldn't cost too much to fix.

Parts shouldn't be much more than £30, but no idea what you'll get charged in labour. Where are you? DH is a plumber

I never tinker with electricity (my dad told me never to tinker with electricity and I have never had reason to douibt him!). We are in central London.