Confusion - modulating boilers vs modulating controllers

[bengasman]

My ex, HR consultant for nhs , told me there are 3 things you should never believe.

"We are from head-office, we are here to help"

"I've sent you a check in the mail"

"I won't in your mouth"

Clever clogs she was.

 

[kirkgas]

send me £50 as well, cause i was really really hurt by the statement and wont get to sleep tonight with all the stress

 

[trevordiy]

The last post was some time ago but modulation has moved on?
I am replacing my 25 year old boiler. I will retain the present system with vented hot water cylinder. I have looked at various controls but am still a little confused. I am considering using the Honeywell Evohome controls. This is a fully programmable system which includes wireless active trv's. I will fit one to each of my radiators. I would also monitor the outside air temperature. I am looking for information that is between the sales blurb stuff and a full technical manual.
For maximum efficiency the boiler needs to operate at the lowest temperature - so that full condensation on the boiler is possible(?) How will the "system" modulate the boiler? If radiators require different temperatures is the boiler set to the maximum required temperature? [e.g. if 10 are nearly at room temp but only one is well below temp] Will the hot water cylinder demand temperature override that required for the radiators? etc.
Is it the controls or the boiler that does the monitoring?
Trevor

 

[Dan Robinson]

The boiler flow temperature needs to be set high enough to do the hot water - so about 70 degrees.

Evo will just regulate the air temperature according to your program.

The outside temperature reference in Evo is from an internet source and has no impact on the heating.