Hi and thank you all for your great insight. I have a new combi boiler (gas) pressure is at the 1.2 bar and the water is fed via the mains supply for both hot and cold.
I thought I would get as much information as possible as the bathroom is being upgraded next week and I don't want to pay someone to come back and redo anything. The workmen said they would install isolation valves and flexi hose pipes to the copper ones and install a thermostatic shower with mixer taps for the bathtub and basin, therefore I won't require check valves unless I am mistaken.
Lastly my kitchen tap is going to be replaced with a lever mixer tap, should I get a double check valve and isolation valve installed on the one kitchen pipe under the sink as their is only one pipe connected to the tap?
