Worcester 28CDi combi boiler, CH thermostat

[Zehroni]

Dear all,
Our boiler (Worcester 28CDi )always set on the first scale of the CH temp control knob. But now it does not fire on this scale since the start of the cold period. When I turned to the fist scale, all I can hear is rapid clicks and both central heating demand indicator and flam detection indicator comes on and off very quickly. It only works when I turned it to second scale despite the temperature inside the house is 4 C. However, I was expecting the both the feed and the return of the CH pipes to get reasonable hot at the second setting before the burner goes off, but they are not, they are fairly warm. Another test I tries is to turn the CH temp control knob to the third setting, both feed and the return of the CH pipes get really hot, I can not even touch them and the boiler keeps firing , is this normal, and any idea why this is happening g, is the CH thermostats faulty or is it not functioning correctly. Any help would be highly appreciated.

 

[Zehroni]

Hi

Reading some literature in this forum, I think one of the ways to resolve this problem is to install wireless room thermostat/programmer. I find Salus RT300 RF Wireless Digital Room Thermostat RT300RF is reasonably priced and would appreciate help with the wiring please

Looking inside my boiler (Worcester 28CDi), I can see, (in the Room thermostat and external control block inside the boiler), the following terminals;
Ns, Ls, Lr.

I believe the Ns should be connected to the N of the thermostat receiver
Ls should be connected to L of the thermostat receiver
Lr should be connected to SL of the thermostat receiver.
Is the above correct?