Query on Worcester Bosch Greenstar 4000, modulation, and which 'Smart' thermostat to choose

Worcester do not support opentherm. If you want the best compatability go with the easy control, this will offer weather compensation or load compensation depending on which setting you choose. all others will give on off demands and rely on the boiler to do the modulating for a stable temperature leaving the appliance.

Modulation is the ability to match boiler output to heat demand. So in that respect they are all the same, with the exception of the easy as it tells the appliance what temperature water to send to the rads.

 

Think carefully before having your installation done by Boxt. The price might be the lowest,but they use a gas safe contractor that once he’s finished and got his cut of the job he isn’t interested in returning to fix snags etc. A friend recently had her system boiler replaced with a 30kw combi Worcester,the brick work outside wasn’t good,tile tiling inside removed in part untidy,and there were noises in the pipes,withe the boiler fan also coming on with the cold tap,so either a dead leg pipe left behind or it needed a shock arrester.
After 2 weeks the boiler broke down and Worcester took 48 hours to replace 2 parts.
I recommend paying a bit more for peace of mind with a local company installer who will return if necessary and do everything to your satisfaction.

 

Worcester control would be best. Weather comp maybe too. Most important is a good local installer. If he/she is interested in doing the maintenance for the next 15years it's probably a good start. If they want to spend half a day plus flushing the system, another good start.