Honeywell CM927 versus Valliant VRC430f

[dumbrill]

I am about to have a new Valliant boiler fitted to replace a reliable, but 20 year old boiler. Currently I have a CM927 for CH control and a 7 day Honeywell timer for HW (ST9100C). The system works well and the optimum start is great.

I am considering whether to switch to the VRC430f as the control for the new boiler. As far as I can see the big difference is going to be in the method of control. The CM927 cycles the CH on and off at the correct rate to maintain the desired temperature. The VRC430f modulates the heat output of the boiler up or down to maintain the set temperature, ie. much less cycling on and off.

Does anyone have experience of both controllers and is it worth spending the £200 on the VRC430f (and VR65)?

 

[dumbrill]

I am about to have a new Valliant boiler fitted to replace a reliable, but 20 year old boiler. Currently I have a CM927 for CH control and a 7 day Honeywell timer for HW (ST9100C). The system works well and the optimum start is great.

I am considering whether to switch to the VRC430f as the control for the new boiler. As far as I can see the big difference is going to be in the method of control. The CM927 cycles the CH on and off at the correct rate to maintain the desired temperature. The VRC430f modulates the heat output of the boiler up or down to maintain the set temperature, ie. much less cycling on and off.

Does anyone have experience of both controllers and is it worth spending the £200 on the VRC430f (and VR65)?

Does the VRC430f have optimum start? There is plenty of comment in the manual about compensation, but no mention of optimum start.