Hi all, I have 2 problems that may or may not be linked?? My sisters heating has just decided to only heat u/stairs rads and HW has never worked from controller and stops CH igniting. Symptoms: Rads have heat u/stairs but cold d/stairs. The rads are on are not very hot The boiler/main pipes clang after about 10 mins of running Hot water has never worked from controller since day one When HW selected from controller the CH will not call for heat from controller or stat Going by the posts I have read it could be one of 3 things: 1.Air in system 2.Pump had its day 3. Boiler faulty, pressure problem The system: Ideal ICOS boiler (combi or condense??) HW/CH header tank in loft - (sealed sytem or vented??) Hercal 110 Cylinder Motorised valve - Danfoss HSA3 Pump??? Controller - Danfoss Stat - Danfoss This a 5 year old house, in plastic microbore, it has TRV's on 8 rads and normal on hall downstairs. A TRV is missing its top in the d/stairs toilet but she says it has always worked fine without it?? I have already done the following: Pump is running in all 3 settings Bled all rads - no air Tested for voltage (I am a spark) when calls for heat on m/valve, tank stat etc and in control box. All present Any advice is greatly welcomed.