Pipe Sizes

[bigwood]

As mentioned a while ago I am re-building my bathroom, starting next monday. Whilst looking at what will be required for the plumbing side of things I noticed the hot feed to the bath taps is 22mm to the tap. The cold is 15mm with a step up to 22mm for the tap fitting.
I know there was a combination boiler fitted as we moved in here and the 22mm pipe came direct from the old imersion tank. I am not shure but I think the new pipes from the boiler are linked into the old feeds somewere.
I had thought of taking the feeds for the bath off the feeds to the sink to make things tidier and easier to get at. Would it be better leaving things as they are This must make sense to some one , I am not looking foward to this project so need all the information I can get to do this job once with the least agro possable.

 

[seco services]

you can take them off the basin supplies but they will more likely join into the 22mm pipe anyway.

 

[bengasman]

The answer is simple: find a RGI that you can trust, and let him get on with it.

 

[seco services]

The answer is simple: find a RGI that you can trust, and let him get on with it.

what to fit a bathroom.

 

[ajrobb]

With a combination boiler, I don't think there is much point having 22mm hot pipes as the boiler usually limits the flow and 15mm is normally adequate. Larger pipes will just take longer to heat up.

With my Baxi Duo-tec 24 HE, I notice that the boiler works harder (fills a bath faster) if I turn up the DHW temperature to 60°C rather than a safer 45°C. As you are re-doing the bathroom, you might want to bring the bath taps up to modern regulations and fit a temperature limiting valve to the bath hot tap. Alternatively, you can use a thermostatic bath/shower mixer tap.

Also, shower temperatures from a combination boiler can be affected by other hot taps. You might want to consider a pressure balancing valve on the shower supplies to prevent cold shocks.

 

[bigwood]

Thanks for the help. I have actualy noticed the hot tap runs cooler if you put it on full flow. I was told that this because the boiler cant keep up with the output from the tap. A gas man told me this when he serviced the boiler, I thought at the time he was trying to be clever but not being a plumber made no coment. If his theory is corect using 15mm with reduce the flow and we should get hoter water.
At the moment the pipes come out of the floor half way along the bath. The waste pipe runs along the floor down a hole in the floor turns 90 degrees and then out through the wall to then goes uphill to the soil pipe. I hope I can inprove this mess on a DIY level.

 

[ajrobb]

I have actualy noticed the hot tap runs cooler if you put it on full flow.

Maybe your boiler doesn't have a flow limiter on the DHW.