Central heating programmer not communicating with boiler

[Corrag]

We had a new boiler installed last year, it has a wireless programmer and has been working fine until today. Now it doesn't seem to be turning on the boiler at the times we have it programmed for. We can fire up the boiler by changing the programmer to the manual setting, or using the boost function, but it doesn't seem to be recognising the pre-programmed times.

For example, this morning it should have come on at 7.30. When we came down at 9.00 the temp on the programmer was 17 so it should have been on (it's set to come on if temp drops below 21) but the radiators were stone cold so it hadn't been on at all. The time/date showing on the programmer are correct so I'm stumped as to why it isn't firing up.

Any suggestions?

Have you checked the batteries aren't running low (sorry very basic suggestion).

The programmer has a low battery indicator and that isn't lit up so I assume the batteries are ok. Thanks for the suggestion though.

What kind of wireless thermostat is it?

At the risk of sounding like an IT person...have you tried switching it off and on again?

wireless stats are not as reliable as wired ones. Change the batteries anyway and move the transmitter closer to the boiler.

Does the boiler have its "thermostat has turned the C/H on" indicator?

Find the instruction booklet and look for the "how to synchronise the transmitter with the receiver" section.

Thanks for the suggestions. I'll try switching it off and swapping the batteries. I considered doing that earlier but I was worried it would lose the connection to the boiler altogether. The instruction booklet is pretty hopeless to be honest, very little info. It's an EPH wireless thermostat.

Sorted, I took the batteries out and put them back in again, it asked me to reprogram the the times/temps and its now working. Thanks for you help.