Hi all, I am new to the site so please bear with me. I have a potterton suprima 50 boiler, a sunvic programmer to control CH and HW and a sunvic digital room thermostat to control heating temps, programmes etc. CH kept permanently on at programmer and controlled at digi stat. HW just at programmer by boiler. House was built circa 2006 so it isn't an old house or system, my problem is that this winter the house will not get warm enough. Around 17.5-18 degrees is all i seem to be able to get. I've done nothing different this winter to the last few. The rads and flow pipe never get piping hot? Heating can be on all day but temp stays as 17.5-18 and not the 20 i want! The boiler seems to be constantly firing up and only staying on for 30-40 seconds at a time before stopping. It is not locking out just flashing green indicating boiler temp satisfied. The system has been balanced for years with TRV's etc where we want them, boiler temp set to max. Also, at time of posting the cylinder stat clicks around 35 degrees, usually kept at high 50's to 60 so not sure whats going on here but have noticed water not as hot as usual. Pressure seems fine, i have reached the end of my limited knowledge. Has anyone any ideas?