https://communities.bentley.com/products/building/performance/f/hevacomp-forum/144815/netsys-chilled-water-pipe-sizing-error-glitchHi All, I&#39;m trying to calculate the pressure drop for a chilled water system which starts with 250mm diameter pipe and reduces in size before it reaches the emitters. The issue i&#39;m having is that even though I&#39;ve fixed the pipework size for flow anden-USTelligent Community 12https://communities.bentley.com/thread/440018?ContentTypeID=1Fri, 22 Dec 2017 10:59:21 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:11209d5c-3748-4c71-a3bd-53b05e4ef2dbShane Regan<p>Hi Jamie, </p> <p>This is not so much a glitch, but a result of the Netsys calculation method. If there are no additional outlets causing such a change in pipe diameter, for example, then&nbsp;the software&nbsp;often overwrites such pipe-size fixes by&nbsp;&#39;healing&#39; such sections together.</p> <p>However there is a way around this. <a href="/products/building/performance/w/building_performance__wiki/19877/duct-sizing-allowing-for-a-depression">This article</a>, while relating to ductwork, is applicable to such pipework systems also. The idea would be to draw three pipes, rather than two, so that there is a pipe section&nbsp;dividing the&nbsp;two that are being &#39;healed together&#39;.</p> <p>Should you have any difficulty then please let me know and I can take a look at your project.</p><div style="clear:both;"></div>