How long should boiler stay on?

[Readingplumber]

Hi again forum, you have all been brilliant in helping me solve the mysteries of plumbing -

On a central heating system - say a y plan - when the boiler is switched on how long should it be firing before the thermostat on the boiler turns off the heat - and then back on -

Am i right in thinking that if the boiler fires up for a bit then turns off then back on that's better than having the boiler continuously on?

PS am i right in saying 90 degrees is the temperature the boiler reaches when it turns off the heat?

Thanks

 

[migoplumber]

depends on the stat setting on the boiler, i like my boilers flowing at 65 on commisioning, returning at 50 ish

 

[Puddle]

How long a boiler stays on depends on so many things
boiler size,burner size,size of heat exchanger,speed water passing through heat exchanger,temp of water returning to boiler,pipe sizes,system size,gas pressures,modulation performance,system controls,boiler thermostat setting,plus
It is better to have a steady heat than boiler going on and off
You will be turning off lower than 90 deg,this is adjustable if you do not have a manual control on boiler,there will be a temp adjustment point on boiler contol pcb