"Fully modulating" combi boilers.

[WaterTight]

What are these? Are most combi's fully modulating?

Looking at possible shower valves for a replacement for a customer who has a combi (can't remember the brand/model) and many seem to be suitable for combi's which are fully modulating.

Thanks

 

[dancinplumba]

yes nowadays, whereby the output of the boiler is reduced or increased, depending on demand, as the water gets hotter so burner pressure reduces and vice versa
imho

 

[Billy Bob Bob]

most combis are fully modulating older aristons and some other brands where 3 stage and could not react quick with a shower in response to temp demand

 

[Jonathan Lisle]

how do i gas rate a modulating boiler ,ive tried in hot water mode and ch mode ,

 

[stevetheplumber]

how do i gas rate a modulating boiler ,ive tried in hot water mode and ch mode ,

there will be a method to ensure full gas rate in the instructuions for the boiler as it varies boiler to boiler

 

[Jonathan Lisle]

i have turned the ch dial and hot water dial to max ,ive looked at the instructions ,it has a potienmeter should i adjust this to max

 

[tamz]

I think you need a bit professional help on this one or you will after you finish playing with it.

 

[GrahamM]

What boiler is it?
The MI's will specify if there is a service mode for running of max rate. Otherwise running the bath and sink taps will create enough demand so that will not modulate down. Just make sure the flow is not restricted by iso valve etc.