Problem with central heating Honeywell room thermostat

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Pls could heating engineer or electrician offer some advice?
My central heating Room Thermostat (Honeywell with a circle dial at the front - I think it’s T6360) on the living room wall(open plan ground floor) is causing the boiler to short cycle repeatedly and continuously once it has reached the temperature set on the thermostat. Room Thermostat ‘clicks’ on and off and so makes the boiler and the circulating pump go on/off - every few minutes - until the programmer eventually turns the system off. I am worried that this may wear out the boiler and / or the pump over the winter?. It is an open vent system with Worcester RI18 regular boiler, Honeywell programmer (st9400c), circulating pump etc.. The room thermostat was changed in the summer, I was told ‘like for like’. It looks exactly the same as the previous 5 years old one, but the previous one was not doing this. It appeared not so sensitive to changes in room temperature.
Have Honeywell changed them or is it a wiring issue? Installer told me as long as the boiler responds and goes on / off then it’s fine and so doesn’t want to return to check it… but that does not answer my question and concern above.
 
I’ve known Honeywell ones fail from new so as above could be faulty or could be missing the neutral.
 
Hi, thanks for replies! Should this be checked and if needed replaced by a gas safe engineer or by an electrician? Sorry if it’s a silly question, I’ve had trade people attending and telling me it’s not for them for similar things in the past…
 
Since it doesn’t involve gas then anyone suitably qualified for electrics, gas engineer, heating engineer, plumber, electrician et al
 
Just checking, so am I right in thinking they don’t need to remove the boiler front cover in order to check the wiring?
 
Just checking, so am I right in thinking they don’t need to remove the boiler front cover in order to check the wiring?
No, as you don’t have a combi all wiring is done via a wiring center.
 

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