Honeywell BDR91 occasionally stops calling for heat (green light goes out)

[FromageFree]

I have a BDR91 wireless receiver and replacement wireless programmer/thermostat.

They are connected fine and when I turn on the heating via the wireless programmer/thermostat and set it to a temperature higher than the room the BDR91 lights up green and fires up the boiler and everything runs.

The issues is, after a random amount of time before the temperature has been reached the green light on on the receiver switches off and boiler therefore turns off. The wireless thermostat/programmer still says it's calling for heat and has not reach target temp, but the bdr91 won't light up and therefore boiler won't fire up. If I manually switch off the heating via the wireless programmer/thermostat and switch it back on the green light will light up and start up the boiler again.

What's the likely issue here? Receiver or programmer/thermostat? Or worth just replacing both?

Distance between the 2 is only 3 meters

 

[JayN]

I had the same problem with that thermostat, I got rid of it and replaced it with something else. My case may not apply to use but I did identify some possible reasons. The thermostat had batteries and was not wired in.

1. thermostat was located a long way from the receiver in the garage, many thick walls
2. I used dodgy/old batteries
3. I switch off the heating between April and October and the problem was always in the winter. Most likely explanation was that my condensing plastic pipe ran inside the cold garage, out the hole in the brick wall and sometimes coverd in snow and got frozen. Problem stopped when I redirected the pipe straight from the boiler through the wall into warm utility room and plumbing.

Then I got a thermostat system so never got 100% certainty.