System unavailable for pipe pressure loss report

[ndavishess]

Hi,

I'm trying to create a pipe pressure loss report, but the system I want (DCW 3) isn't on this list. I made sure the system had calculation set to all. Does anyone know why it's not a system to choose from?

Thanks!

[iainsavage · Accepted solution]

This happens if the system is not "well connected" so Revit is not able to analyse the flows properly.

System Inspector is probably not available for that system as well?

[ndavishess]

Yes that was it. Also the flow direction, ie. inlet and outlet of my valves, were flipped, so I was getting negative flow rates in some pipes. Make sure your families and accessories are all pointing in the right direction 

[iainsavage]

Most accessory families such as valves will have connectors set to Fitting (which is inherently bidirectional) or Global and Bidirectional.

Is there actually a need to have them as single direction?

[robert2JCCH]

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@iainsavage wrote:

Most accessory families such as valves will have connectors set to Fitting (which is inherently bidirectional) or Global and Bidirectional.

Is there actually a need to have them as single direction?

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Admittedly it's a funny way to make sure your designers draft/model check valves in the right direction 😋

[iainsavage]

For check valves yes, but no need for isolating valves?

[ndavishess]

Yes - this are the flow directions when I turned a valve around. Notice how the flow is exiting all three pipes. This messes with your flow rates/ calculations etc. 

[robert2JCCH]

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@iainsavage wrote:

For check valves yes, but no need for isolating valves?

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Yeah it's probably not needed for all use cases. Just a few specific conditions (check, backflow, triple duty, strainers).

[iainsavage]

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@ndavishess wrote:

Yes - this are the flow directions when I turned a valve around. Notice how the flow is exiting all three pipes. This messes with your flow rates/ calculations etc. 

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I understood that - your families must have directional connectors in them (In or Out).

Unless you need that function you can change the connectors to Bidirectional to simplify your modelling by avoiding the need to flip the families.

In the case of real single direction valves (as listed by @robert2JCCH ), you can still use Bidirectional connectors and rely on the valve symbol to show you if its the correct way around but if you do accidentally fit it back-to-front your flow calcs will still work.