Currently we have a Potterton Profile 55e that works well and is very reliable.

Due to changes in the layout of our heating we tend to run it at a low return temperature, as hot water is done purely by solar.

Would like to change existing gas valve to a variable (modulating type) to reduce boiler cycling when coming up to house target temperature.

Does any one have experience of doing this.

Our plumber says he has heard of this being done before and if I can source the parts he is willing to fit and commission system.

Benbecula, January 2010

you can't do this the only thing you can do is adjust the burner pressure down and that will not be the solution your after on the profile there is no modulating gas valve simply burner on or off no low flame high flame unfortunatly

Richard boiler engineer, February 2010

Your plumber should be registered to mod the gas valve would contravene regs. to alter the boiler spec.
Could try weather compensation electronic control but would consider not worth the cost

a, January 2010