Had a painter in earlier in summer. He took thermostat off wall, painted wall, and replaced thermostat. Now want some heating but found the batteries exhausted. Replaced them. Painter lost the small screw underneath. Now seems the weight of the 2 AA batteries is causing intermittant connection. Have actually tried turning unit upside down so the weight of batteries leans on connection, but still intermittant. Think the design is very poor, as batteries are heavy conpared to flimsy plastic holder. Do I need to buy a new RF603? If so, will the new model automatically connect the RF frequency?

Juliette, October 2015

It's a pretty standard machine screw which you should be able to get from any ironmonger or DIY store.
But the problem is probably a film over the contacts. When mine died, I scraped the bar on the battery-holder, and made sure the contacts in the unit itself were clean and sprung out. My dead thermostat then came back to life.

EricB, June 2020