boiler/cylinder efficiency

[PDrawmer]

Will it make my system more efficient if I set the cylinder temp higher than usual (say 70) and use a TMV for HW distribution; then set the boiler so that it doesnt fire for HW until the cylinder drops to 40?

The cylinder has 50mm insulation, and I've read somewhere(!) that modern boilers work best when they are working hard.

Planning a new install, so would be using a new boiler and a cylinder with a 'high recovery' coil.

 

[billy bob]

In my opinion, No, why heat the water higher than you need it, to then cool it down with a blending valve, why not just heat your water to 50 deg C that would be far more efficient, if a boiler is constantly working hard to acheive the heat required it would of been undersized, the boiler should only work at its maximum a few days of the year, when its very cold, you need to ensure your house is well insulated to retain heat produced by the boiler and hot water set to a temperature that can be used withoutr cooling that would be efficient, as for legionaires, most modern boilers have a legionaire program that heats the boiler to 65 deg C once a week

 

[PDrawmer]

In my opinion, No, why heat the water higher than you need it, to then cool it down with a blending valve, why not just heat your water to 50 deg C that would be far more efficient, if a boiler is constantly working hard to acheive the heat required it would of been undersized, the boiler should only work at its maximum a few days of the year, when its very cold, you need to ensure your house is well insulated to retain heat produced by the boiler and hot water set to a temperature that can be used withoutr cooling that would be efficient, as for legionaires, most modern boilers have a legionaire program that heats the boiler to 65 deg C once a week

Thank you for taking the time to answer my question.
Yes the house is well insulated, I'm talking about a new boiler/cylinder install, and HW performance.
I'm exploring the possibility and use of the TMV in order to maximise the temp difference between boiler on and off, only because I had heard that the boiler works better when it is working hard.
Basically; is it better to have long cycles where the boiler has to raise the cylinder temp more, or short 'top-up' cycles?

 

[simond]

You may like to take a look at the ACV Heatmaster 35TC.

This is a boiler that produces all hot water in condensing mode. We have just started fitting them.

It also supplies up to 40l/m either open vented or unvented.

 

[PDrawmer]

Simon, thanks for the reply.
I'm an ex Combi user.