DHW in (cold feed) to combi boiler IDEAL ISAR 30

[jon]

Looking at the diagram, I'd imagine that C is the most optimal solution. But could I get away with either A or B.

[Doctor Evil]

is optimal, and I would go for that. B is next best. Avoid A. The only time A is effective is when you have a large bore high pressure cold mains pipe, which I doubt you have.

[Ed Sirett]

I am aware that there are other view points on this matter.

Whilst C is the preferred layout depending on other circumstances B and even A may work well.

If you have a standing mains water pressure of more 3 bar and up then even A will work fine. Even if you have only a fair water pressure then provided that there is a reasonable flow rate then A will still work. At worst if you have some restriction on the branches to the bathroom and kitchen A can be made to work well.

As a rule if you can get >15 l/min from the cold taps you should be OK. Less than that you _may_ be OK.

I hope this may save you tearing your house apart unnecessarily.

[Doctor Evil]

>

The main point is influence of appliances on the showers and DHW. "A" may mean cold tap turned on seriously affects the shower, "C" may mean the influence is minimal. You want the line of least resistance to go to the combi's inlet. Even if a 15mm cold mains pipe, having a 22mm stop c*ck and the combi supply in 22mm and the C setup will be good insurance.

Also

sell flow restrictors now. These can be fitted on supply legs and individual taps. They are about £4 to £5. These could be used with setup B.

[jon]

Ed,

Just tried this and managed 4 litres at 15secs, so that's approx 16l/min. So I should be ok

Jon