Replacing water pipe

[jeeves]

Hello

I am going to replace the existing copper water pipe that runs from the incoming mains to the boiler. This is due to an extension and change of the incoming mains.

Currently the incoming is 25mm MDPE which at the moment reverts to 15mm for a distance of about 8m which then goes to 22mm for about 6m then reverts again to 15mm for about 2m before entering the boiler via a 15mm connection.

My question is, while I am replacing the pipework is there any need or advantage to running it in 22mm all the way to the boiler? Or because the boiler connection is 15mm is that the limiting factor?

I suppose the same question applies to the hot water from the boiler (The out coming hot from the boiler is 15mm).

Thanks in advance!

 

[muggles]

Upgrading to 22mm all the way will make an indiscernible difference, if any at all, as the boiler will almost certainly limit flow rate internally so that it can heat the water going through it effectively. The only way to get a higher flow of hot water is to buy a more powerful boiler.

 

[jeeves]

Thanks for your reply, so from that I assume that if a boiler would benefit from a 22mm feed, it would have a 22mm tail?

So as my boiler (Atag E32C) only has a 15mm it would as you say make no discernable difference.

 

[muggles]

In general your boiler will come with tails specific to it, so if the tail supplied with the boiler is 15mm for the hot coming out then running 22mm into it isn't going to help. You can check how much flow there is through the boiler roughly, using a bucket and a stopwatch, although for accuracy a good digital thermometer is also required. the E32C should produce 14L/min of hot water at a temperature rise from the mains temperature of 35ºC, IE if the mains is 15ºC then the hot water should be flowing at 14L/min when it's at 50ºC. If the water is hotter the flow will be less.