The HWS Secondary Return pump sizing circuit resistance pressure drop always seems to be astonishingly low and can't be used with any confidence in pump selection (in fact the Hevacomp pump selector returns no results). Is this a common issue for users?
Hi Paul,
We have had no reports of this from any other users. For us to investigate this for you we would need to see the project (or an example project) along with a detailed hand-calc showing the result you would have expected. If you wish us to look into this further, I will log a Service Request to obtain these files off you.
Shane Regan | Principle Building Performance Support EngineerHevacomp to OpenBuildings - A complete guide for every user | Bentley Communities
Hi Paul, thanks for uploading your project. We have looked into the project inputs in depth and the return pump pressure is being minimised mainly due to the temperature constraints. Specifically the temperatures defined at your System Marker, and the surrounding temperature set in your pipe defaults.
Firstly, I note a minimum circulation temperature of 55deg - please note that this is the temperature at the furthest outlet from the System marker, as apposed to at the cylinder. Please ensure this meets your requirements.
By default the surrounding temp in the software Defaults is set to 10deg - in your project it has been set to 20deg. This, along with the insulation on your pipework, means that there is very little heat loss across the system.