15mm vs 22mm pipe

We have just had a 30kw worcester bosch combi boiler installed in our property - with 15mm infeed and DHW pipes as per the manufacturers guidance. The issue is, we have installed 22mm pipes for all the hot water outlets (shower, bath and hot taps) in an attempt to improve flow. Is there any risk of performance being impacted from the hot water leaving the boiler going from 15mm to 22mm? (the water mains supply is 32mm PDPE).

Replies from 3 tradespeople

Yes this will reduce pressure as you are changing from but the issue is how much of a 15mm pipe you're using how long if it's a short distance that shouldn't be too much of problem

No risk and it want improve

The boiler is designed to run efficiently on a 15mm supply and feed to taps. Increasing the bore of the pipe will severely reduce the pressure at the taps

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