piping help - 15mm, 22mm

[chrislewis10000]

Hi

wonder if anyone can help. 2 years ago I had a new valiant 28 combi boiler installed and got rid of lead piping etc. It cost a small fortune but i'm not that happy with it - if having a shower and the toilet is flushed, or worse the hot tap in the kitchen is turned on it turns into a piddle.

My set up:
New blue 25mm MDP enters house under stairs. IT then turns straight to 15mm and goes through about 6 right angle bends for a stopcock then to click pipe with a 15mm. It then splits - one pipe to feed kitchen cold and the other goes upstairs to the combi boiler, then to the cold tap for bath, then follows round to the sink and finally the toilet. Lastly 15mm hot comes from the boiler and splits one goes downstairs to the kitchen the other goes under the bath - it then looks like it turns into the old imperial 22mm piping going to the bath/shower tap and then branches off for the hot on the sink.

Would it make sense to change the cold feed to 22mm? I might be putting an extension on in a few years with another shower/toilet on the other side of the current bathroom. I'm changing the old bathroom and want to make sure it can be easy to fit another without ripping up all the new tiles etc..

Any help greatly appreciated.

Chris

 

[muggles]

Is your stopcock fully open? That might make a difference. Your combi won't satisfactorily run two showers at the same time though, so if you're going to be adding another one you'll need to find space for a hot water cylinder somewhere

 

[dilalio]

You are governed by the working pressure and flow of your incoming main. This dictates the size of combi boiler that is feasible and therefore also has a knock on effect at what you can expect at all outlets!
Demand, Pipe runs, bore size, bends and highest point of system are all also depreciating factors. As can gas supply be if the water main can serve a larger boiler but the gas cannot.
Unvented will make a difference as hot water is stored and doesn't have to pass through plate HE: incoming cold flow and pressure just has to push it through cylinder.
Vented will remove strain from incoming main but means a tank in the loft.
There are other things you can consider such as a break tank or accumulator but they come at a cost and with their own connotations.

 

[PullerGas]

Hi

wonder if anyone can help. 2 years ago I had a new valiant 28 combi boiler installed and got rid of lead piping etc. It cost a small fortune but i'm not that happy with it - if having a shower and the toilet is flushed, or worse the hot tap in the kitchen is turned on it turns into a piddle.

My set up:
New blue 25mm MDP enters house under stairs. IT then turns straight to 15mm and goes through about 6 right angle bends for a stopcock then to click pipe with a 15mm. It then splits - one pipe to feed kitchen cold and the other goes upstairs to the combi boiler, then to the cold tap for bath, then follows round to the sink and finally the toilet. Lastly 15mm hot comes from the boiler and splits one goes downstairs to the kitchen the other goes under the bath - it then looks like it turns into the old imperial 22mm piping going to the bath/shower tap and then branches off for the hot on the sink.

Would it make sense to change the cold feed to 22mm? I might be putting an extension on in a few years with another shower/toilet on the other side of the current bathroom. I'm changing the old bathroom and want to make sure it can be easy to fit another without ripping up all the new tiles etc..

Any help greatly appreciated.

Chris

It would certainly make sense to replace the 15mm with 22mm tube from the stopcock Chris. While this will not improve the pressure it will improve the cold water mains flow rate. Taking a dynamic pressure & flow rate would be a good idea before planning further extension to your system.