Problem with SUNVIC control

Hi
we have a SUNVIC SELECT XL control untit for out hot water
[broken link removed]

the +1hr and ADV buttons are no longer doing anything, nor can we get it to work by programming it to come on. But the display is still working and it allows us to reset and change the timing etc.

Trying to work out if the unit is Kaput and needs replacing or if it could be a simple issue like a loose wire etc. The last time it did work it took a few prods of the +1 hr button to get to work.

Money is mega tight at the moment so want to exhaust the DIY option first. (we have replaced one of these units previously as we had two one HW second Heat). Unit is just over 2 years old.

Thanks

Had a similar problem with the same model, called an electrician and he told me over the phone I would need to have it replaced, went out and bought one and replaced it myself. Cost me 48euro

have you tried simply changing the backup battery?

Thanks for responses. With respect to the backup battery I was assuming that the purpose of it is to hold the programme settings in case of loss of power supply to the unit, I have a spare battery anyway so will check that out. Was just about to take it all apart when I realised I have a wash on so can't touch it until that is done and I can turn off the main power switch. At least the sun is shining today so the solar panels will supply some hot water!
Stephen - what model controller did you replace it with? Just in case my DIY proves to be a disaster!

Yes, but if the battery has gone and you have a momentary power cut the unit will fault and not work until everything is reset

The 207 model, easy to replace

http://www.heatingsupport.co.uk/gallery/albums/products/sunvic-new207.jpg

Thanks for that DGOBS, will check the backup battery. Between solar /geothermal and underfloor it is like the starship enterprise in our hot press! And to add to it the washing machine decided that it will assume all washes are 100 degree washes and should go on for 4 hours at least !! So all in all a technology nightmare day!
Stephen - thanks for web link, much appreciated.