Advice on a wireless thermostat problem please?

[Sue]

I have a wireless programmable thermostat - a Salus RT500RF.

I had had it about four years with no problem at all, when out of the blue the boiler started going on and off randomly - so for example even if I turned the thermostat down to 16, I'd get up in the morning to a hothouse with the living room temperature in the 20s.

The flame symbol on the thermostat wasn't showing, but the light on the boiler was green.

I had to turn all the radiators off to try to save gas, plus it was driving me mad(der) when the boiler kept going on and off all night :(

This would happen for a while, then it seemed to correct itself for weeks, then it would start again. It's out of its guarantee period.

Long story short, I phoned the manufacturer who said that this was an old style of thermostat. Basically what was happening was that something else within the wireless range was controlling the boiler, such as another boiler thermostat (or I've found on the internet it could be a wireless baby monitor or doorbell, though I can't see how that could control a boiler). The problems did start around the time that I had new neighbours, though obviously that could be completely coincidental.

Basically I was told that the solution was to change the address code/frequency. I know how to do this and it seems quite easy to do. There are five possible frequencies.

I know this seems a very stupid question, but do I have to keep on changing the frequency until I find one where there's no interference? Given that the problem is so erratic, it might be weeks until there was interference (and I actually noticed it - which generally I only have done because the temperature has suddenly shot up when I've been there).

Will this actually resolve things, or do I have to bite the bullet and pay again to get a different kind of thermostat? This one hasn't got great reviews on forums, but on the other hand that may be because people don't realise that this problem can arise.

[right-clicking]

Hello Sue, below is a list of popular frequencies. avoid 2.4 & 5.00 GHz (wi-fi)

Garage door openers, alarm systems, etc. - Around 40 megahertz

Standard cordless phones: Bands from 40 to 50 megahertz

Baby monitors: 49 megahertz

Radio controlled airplanes: Around 72 megahertz, which is different from...

Radio controlled cars: Around 75 megahertz

Wildlife tracking collars: 215 to 220 megahertz

MIR space station: 145 megahertz and 437 megahertz

Cell phones: 824 to 849 megahertz

Hope this helps!!

[Sue]

Thanks right-clicking, the only problem is that all I have are five black jumpers on the thermostat labelled 1 to 5 and five white switches in the receiver, also labelled 1 to 5.

I have no idea what frequencies these numbers correspond to :))

All I have is some instructions off the internet which say "we have found the removal of blocks 2 and 4 to be very successful" :))

ETA: So I guess I'll try that then :))

[Huguenot]

Hi Sue, I don't believe that you're changing the frequency when you change those jumpers, I believe you are changing the RF code (or 'tag') of the transmitter.

It will always operate at 868MHz.

Unless the transmitted code matches the receiver code, your thermostat will ignore the message.

Hence change the code, and so long as your transmitter and receiver match, it will simply be a case of trial and error to find out which one is least likely to suffer from interference from others nearby.

FYI, the most likely interference is from another thermostat (they can transmit over 60m), and then possibly from a poorly calibrated cellphone. Either way, changing the identity code on both transmitter and receiver to a different match should fix it.

[Sue]

Thanks Huguenot, that's very helpful.