Do you have a combi boiler?

[Battlefront]

If so what happens when you turn on another tap/flush a toilet if someone's in the shower?

In our house you MUST NOT turn on any other tap while someone's showering - the shower instantly runs freezing cold.

Is this normal or was mine fitted by cowboys? What happens if you have more than one shower - the point being that more than one person can shower at a time?

tank fed bathroom makes sense to me, as you were getting such a lot of flow.

some people are surprised that a tank and cylinder can fill a bath faster than a combi.

make sure that the cold tap is also tank (if hot and cold are different pressures, a shower or bidet mixer will not give a controlled temperature)

Ah, no, the cold basin tap seems to be mains fed (can't stop it with my thumb). What does that mean for boiler choice? I should add here that the downstairs bath will be removed soon and replaced with shower in upstairs family bathroom.

So where there is already a combi boiler adding an extra shower would ideally be eg power shower or solar heated separate thing?

Wendy
That is very common.
Check with your bucket again the flow from the hot and cold bath taps. It will be unusual if they are both the same. If you feel the pipes, I think you will find the 22mm pipe is hot from the cylinder, and the 15mm is cold from the main.

Isabeller
if you have a combi, you can't have a power shower. A power shower sucks water out of a cylinder that is supplied from a loft tank and pressurises it. (However if you have both a combi and a tank, you can. This is uncommon but can be useful especially in larger houses.)

You can have an electric shower (though it will be very weedy, especially in winter) which you can also use when your combi breaks down.

However with no loft tank, the amount of water that comes out of your electric shower, added to the amount of water that comes out of your combi, added to the amount of water that comes out of your cold tap, WC cistern or washing machine, at any one time, will be limited by the amount that the incoming water main delivers, so turning one on will reduce the flow from the others.

If you are lucky enough to have a large incoming water main that delivers, say, 30 litres per minute, then you will have plenty to go round. If you have a small flow of 12 litres per minute, that will be very poor when shared between two or more taps.

You can use solar to heat a cylinder, but the source of heat is irrelevant to the amount of water flow.

that's why I so often ask people to fill a bucket at the kitchen sink and calculate incoming litres per minute.

In keeping with the flow topic
Why is it piglet that on Saturday mornings I get no water to my shower....
I'm last in row of 6 Victorian terrace, combi boiler. It's my flow that seems to be affected and I'm guessing it's because all the neighbours are at home....?

yes, it might be that your neighbours are all washing their cars or something, or maybe the person next door has an illegal pump on the mains sucking the water out.

you could ask your water company to investigate.

Added to my to do list
Thank you

Yes Piglet, you are right the 22mm pipe is the hot and the 15 the cold. Remeasured flow from both bath taps and they really are the same (fill a 14L bucket within 1 second of each other - 31 seconds on the hot and 32 seconds on the cold).

I had a power shower with my old gravity system, which has 4 side jets. It worked fine with an electric pump of 1.5, the same as my mains water pressure. My brother could not understand why a combi with the same pressure would not work? I had the pipework rerouted to supply the power shower, with the appropriate combi-pink ---- ( forgotten the name of it) Aqualisa installed. It actually worked fine, until I heard a trickling behind the shower head and behind the back wall tiles after being turned off. There was a leak which ran into the adjoining room. Had the emergency plumbing insurer come and he just cut the pipes and capped them.

you need both pressure and flow. A tank can have lots of flow, and the pump increases the pressure.

with a combi or other system fed off the watermain, you are limited to whatever flow the pipe gives you - might be 30lpm, might be 10.

You are not allowed to put a pump on the incoming main as it will cause suction and (1) prevent you neighbours getting enough water (2) cause contaminants to be sucked into the supply.

1.5bar of pressure is what you get from a tank mounted 15 metres above you (quite a lot) or from a pump.

Aqualisa make some very fine (non-budget) showers, including some with pumps.

Remembered the correct name - Aqualisa pink cartridege especially for combis. It was ok until the leaking in a pipe after Power Shower was turned off. My brother reckoned that there had been a leak before, but when turned off, it stopped leaking, whereas with the mains pressure it was too strong. But the Aqualisa cartridge is designed to stop this happening. The leaking into the shower cubicle stopped, but I heard trickling behind the shower head/tiles. Still not sure if it was a leaking pipe, as when turned off, the water inlet should have stopped too. The leaking carried on for days, before I discovered water on the floor in the next room, and had not actually used it.