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dt20rf rf light flashes?

the dt20rf receiver rf light flashes, and does not seem to be controlable at all, is someone else nearby using one that would interfere with it or is it something more problematic, there is no troubleshooting guide or troubleshooting help from worc bosh
Andrew, January 2009
Thank you so much for posting the solution to the flashing green light!

B H, March 2023
This one defeated me too, in my case a Worcester Bosch Group DT20RF Programmer with Digistat radio frequency controlled room thermostat – until I read the blogs and saw a lot of other people have been having the same problems as me. I am neither an electrician nor a heating engineer but I do handy work for a letting agent, so I am called to all sorts of central heating and hot water problems – all of which I can usually fix or diagnose for the experts

So, here’s the combined wisdom of 3-days searching blogs, reading manuals and system testing


1. the radio control on the thermostat seems to only have about a range of 2 meters. This is not mentioned anywhere in the manual. In fact, the manual talks about all sorts of potential places to put the thermostat but not that any of them should be within 2 meters ! a distance which frankly makes any other suggestion pointless. I have lived with mine positioned around 4 meters for a year, giving me a previously inexplicable, intermittent system. One blogger suggested a range of 2 meters is probably ‘about right’ so I did a test. I took the thermostat to the furthest point – the back bedroom and immediately the boiler couldn’t ‘see’ the thermostat – the green light flashed and the Mode was locked out; I then sat the thermostat on the cover of the boiler, and it all came back on within a few 10’s of seconds

2. When the boiler can’t ‘see‘ the thermostat, you get a flashing Central Heating Light the Worcester Bosch boiler. Their manual does not mention anywhere what this means. Added to this, the Central Heating Mode defaults to OFF at the same time, which you can’t change by pressing any button. The actual solution is to get the radio control thermostat close enough to the boiler so it can read the signal. You could spend a lifetime . . !

3. BTW Whilst we’re on the subject, the thermostat is counter intuitive:

a. you can see the room temperature on the thermostat but not the set temperature
b. to get the set temperature, you need to turn the dial – but then you’ve changed the set temperature [by ±1°C]
c. when you dial the temperature you want, whatever you do, don't press the obvious Set button, because that wont set the temperature you want, but instead it will reduce the setting to the default minimum of 15°C – you’re supposed to hit that when you go out. You could easily think though, that you’ve turned up the heat when in fact you turned it right down – remember, you can’t see the Set temperature
d. the thermostat reads in ½° increments but only sets in 1° increments

(what was wrong with a dial and pointer ! ? )


BTW I did speak to Bosch afterwards and eventually, after describing the problems to 3-people, Jez was able to say (a) just turn the thermostat to the desired temperature but don’t; press SET and (b) the remote thermostat has a 9-meter range but is affected by other things eg: mirrors, RSJ’s etc. If the central heating does flash red, just press the OK button

Shaun the Handyman, October 2013
It sounds as if the remote isn't paired to the receiver.

Prep - remove batteried from the remote stat first.

Receiver set up:
After initial start up, the colon, CH and antenna
symbols should be flashing on the display.
1. Press the set? button 4 times.
2. Press the OK button once.
3. Press the set? button 4 times; Lrn and OFF
should be displayed.
4. Press the + button so the display shows ON and
a flashing antenna symbol. The learn mode is now
ready to receive a signal from the transmitter during
the next two minutes.

Transmitter set up:
1. Take the Digistat Room Thermostat and stand
approximately two metres away from the boiler.
2. Remove the battery cover and refit the batteries.
The symbols on the receiver will stop flashing and
the display will return to the normal time display.
This confirms that the radio signal is being sent
and received.
The Digistat Room Thermostat is now linked to
the receiver on the boiler.

Chunkmeister, November 2010
http://www.worcester-bosch.co.uk/cache/file/12/dt20rf-digistat--mk-1.pdf

cut and paste that link it might help

b, January 2009