I wonder if any of you could help me with this.

We have had Evohome for quite a few years now. It's worked flawlessly, keeping to setpoints and utilising optimum start really well. However, since the inclusion of advanced load scaling and cold weather boost things have started to go awry.

Over the last few weeks as well all know the weather conditions have fluctuated quite a lot. This has led to days where the system has applied cold weather boost along with optimisation to get rooms to temperature at set point. The problem is they never do.

For example today our downstairs room sat steadfastly at 3 degrees below setpoint. The system parameters screen showed the BDR91 at no more than 40 percent with the downstairs area showing as 100. The flow temperature for the boiler is set at a maximum of 70 degrees for CH. This leads to the actual flow temperature being too low to heat the room. The room is set to be at 19 degrees (boosted to 20) by 5.50am. My wife eventually gave up waiting for it to heat at 11am and set the temperature to 21 degrees. This activated the boiler and the room heated.

Our load scaling is set to normal. I have tried partial in the past few weeks to see if that helps but to no avail.

We are using the evohome unit as the temperature sensor in the downstairs zone, but this problem is replicated across the house - when the temperature is cold the system seems slow to react to the changes and the setpoint is never reached on time.

I am thinking of swapping out the BDR91 for an Opentherm bridge. Our boiler is an Atag installed last year and I considered at the time to change it then but was talked out of it by my installer as he said it wouldn't be worth doing. Should I just bite the bullet and do the swap? Will this work better?

It has become really annoying as like most people on this forum I just want the system to work without much interaction. For us at least this software update has been a step backwards.