Water pipe sizes

[raindropsarefallingonmyhead]

I need some advice on water pipes please. So, incoming main from the road is 32 MDPE. We are having an unvented pressurised hot water system so I am surprised to see the plumber has dropped to 22 copper at the internal stopcock. From here the supply enters a water softener and then onto the cylinder. Surely we need a larger pipe size as far as the cylinder to ensure good flow rate to multiple showers/baths etc. Does the softener require a smaller diameter pipe perhaps? Plumber already thinks I'm a idiot so I want to have my facts straight before I speak to him. Very grateful for any advice.

Are you around PigletJohn? I have read a previous response of yours where you say 22mm internally is fine but would 28mm to the cylinder be better for a large house? Thank you.

Look up b the water softener on the manufacturer's website to see what diameter pipe it needs.
I wonder whether the drop in diameter at the stop tap might cause pressure and issues with the tap.

As the previous poster mentioned check what diameter the water softener requires. I can't comment too much on water softeners as i've little experience of them as live in a soft water area.

A 32mm incoming cold main is large for a domestic property so can only assume it's a large house. If so how many bathrooms and following on from that what is the volume in litres of your unvented cylinder and do you have good pressure on your cold mains supply?

Even the 300 litre Worcester cylinder i fitted a couple of weeks ago was supplied with only a 22mm control block and 22mm connections into the cylinder. The control block includes a pressure reducing valve that regulates your water pressure down to anything between 2.0 -3.0 bar or thereabouts. This means that assuming you have good water pressure, allowing for a bit of frictional loss, reaching the pressure reducing valve, you would have more water, greater flow and pressure reaching it than you would have on the outlet side of it to the cylinder.

All that said, if it's a 28mm control block then it needs a 28mm pipe to it.

I'm sure we upgraded from a 1960 18mm to a 22 and it's fine, 3 storey house 4/5 bedrooms. Shower on every floor unvented cylinder system

Thanks all. We're going to stick with 22mm pipes as it's too late to change. Hopefully it will be fine.

32mm plastic is very big, but becauss the plastic walls of the pipe are thick, the internal diameter is smaller. I can't remember it. 22mm copper inside your house is enough unless you have a hotel or something. Look out for the size of any stopcocks or service valves, including round the softener, because the full-bore ones are more expensive and sometimes omitted.

22 is the larger option for internal pipes. 16 is the crap option.

Plastic 32mm Internal diameter is about 26mm

Copper 22mm and plastic 25mm both about 20mm internal

@RandomMess you might have changed from imperial copper 3/4" to 22mm, they are nearly the same but measured differently.

@PigletJohn I can't remember now I just went with what you told us 🤣

Involved digging up our drive and my miserable neighbour being grumpy but worth every penny.

Was it a steel pipe?

I can't remember but the house was finished in 1960 so what was the norm up north in the late 50's 🤷🏽‍♀️ definitely was a bigger one.