Salus RT500RF 434MHZ not switching off the boiler

[MrTeeny]

The transmitter doesn't have a problem switching on the heater but doesn't seem to switch it off unless it's very close to the receiver. Does anyone have an idea of what could be wrong or how to fix it? It's one of the older 434MHZ ones.

I thought it might be a problem with the range but the fact it manages to comminicate switching the receiver on from a distance seems to suggest it's not a battery or weak transmitter. I've changed the settings to a different channel but the problem's still there. Does anyone know how often they transmit the on/off requests to the receiver? Or is it a single request when the boiler flame goes off on the transmitter.

Thanks

 

[bernardgreen]

One possible cause is radio frequency energy radiated by the speed controller driving the fan in the boiler blocking or degrading signals at the receiver This RF energy exists only while the boiling is running so the "turn on" signal is received but "turn off" signals are then blocked by interference from the fan.

Salus do say

To ensure trouble free operation of the Radio Frequency (RF) signal, always ensure that the programmable thermostat is mounted away from any possible sources of interference (such as radios, TV sets, computers, etc.), and is not mounted on or in close proximity to large metal objects.

but do not mention the large piece of metal that is the boiler and the possibility of an electronic speed controller inside the boiler creating radio frequency radiation that will affect the receiver.