What is the water system from 2 sources

BobbyJoe · Apr 8, 2021

Hi everyone,

Just discovered that my flat has a water tank in the attic which feeds the hot water into the building and the cold water is mains fed. My question is what kind of system do I then have when hot and cold are coming from different sources?

I turned all the stop cocks off (3) in the flat and all the cold water outlets had no water, however the hot water was still able to run despite this.

Also does this affect the type of taps I have or combi boiler? Just want to make sure that everything is the way it is supposed to be for example the flat has high pressure water and I then should have the right pressure taps, any info would be great thank you.

Aquarius · Apr 11, 2021

BobbyJoe said:
Thank you, do I need to turn the boiler off before turning it

No, not needed.

BobbyJoe · Apr 11, 2021

Fantastic thank you, I gave it a try and yes it turned the hot water off in the kitchen and bathroom;

So is the system in my flat all mains fed?
Do I need any NRV/ or single check valves? I live on the top floor and have two flats below me.
Lastly with combi boilers their is no chance of legionaries since their is no stored water is this correct and it doesn't matter what temp I set my DHW to it ranges from min 38 to max 65 degrees.

Thank you all so much you have been incredibly helpful 😀

Ric2013 · Apr 11, 2021

BobbyJoe said:
Fantastic thank you, I gave it a try and yes it turned the hot water off in the kitchen and bathroom;

So is the system in my flat all mains fed?

Do I need any NRV/ or single check valves? I live on the top floor and have two flats below me.

Lastly with combi boilers their is no chance of legionaries since their is no stored water is this correct and it doesn't matter what temp I set my DHW to it ranges from min 38 to max 65 degrees.

Thank you all so much you have been incredibly helpful 😀

1. Correct - which explains why your 0.5 bar taps work well.
2. For taps, no, as you have balanced pressures. Though the check valves you have are doing no harm so no need to remove them.
3. In short, your understanding is correct.