hydronic supply or return?

[Anonymous]

When does revit consider supply to become return? Does the pump determine whether it is supply or return? or the terminal?

AJ

[KyleB_Autodesk]

Alan,
Up to you really...based upon the Flow Direction and System Type of the Connectors on the System, you could set up a System however you want.

The limitation here is what can be defined as a "Child" of the System and what can be defined as the "System Equipment".

For a Supply System, the Flow Direction needs to be "In" for all "children", and System Equipment has a Flow Direction of "Out". The opposite applies to Return systems.

Generally I have seen it relative to the Terminal, but it doesn't have to be that way. We designed the framework to be open in this way.

Cheers,
Kyle B
Revit MEP Product Manager

[Anonymous]

I think I understand now. So the important thing is that an IN goes to an OUT and an OUT goes to an IN. But you could have 2 supply or return systems for one equipment family, is that correct? So if a pump were inline on the return system, i could have a return IN to the pump and a return OUT of the pump. Correct me if I am wrong.

Thanks

-
AJ

[Anonymous]

Alan, I think those damn arrows on the connectors throw everyone off. Kyle, please correct me if I'm wrong here:

The arrows on the connectors that you see in a family just point towards where the physical connection is coming from, irrespective of it being flow or return. Open up a supply air grille and a return air grille family and you'll see that the arrows point the same way - towards where the the duct is coming from.

However, check the element properties of each connector and the supply grille shows Flow Direction as In (you're effectively pushing air IN to the grille), whilst the return air shows it as Out (you're effectively pulliing air OUT of the grille)

In the case of your pump, the arrows on the connectors would always point away from the pump, towards the piping. And the element properties of the connector on the inlet side would show Flow Dircection as IN and the one on the outlet side would show it as Out.

As far as I can see, as the fluid always travels in the same direction, that would be the case if you were using the pump for return or supply.

[Anonymous]

I have VAV reheat coils, a pump, and a faked in boiler because this building ties into a university central plant. Based on my understanding of Revits parent child behavior, the reheat coils should be make up a system served by the pump (equipment) and the pump should make up a new system served by the boiler. Unfortunately, when I select all of the coils, create a system, and try to select the pump as equipment, the system will not allow this. Are pumps to be treated as another system component with the coils?

[Anonymous]

i have had a ton of issues with the system creation. i think there are just limitations. for example you cannot have multiple pieces of equipment serving multiple terminals (ie. a set of pumps serving terminals). no one uses one pump for all their coils, you have multiple with backups, but i see no way of selecting more than one piece of equipment for a system.

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aj

[Anonymous]

Can you tell me how you are treating the coil-pump-boiler relationship? Is the boiler a parent to all of the coils as well as the pump, or is the pump a parent to the coils, and the boiler a parent to the pump?

[Anonymous]

Alan,

I am facing the exat same problem: adding redundant/backup pumps to a same system. It is NOT possible to do it, at least I haven´t found a way to do it.

Do you have any news on that? Have you found a way to do it?

Best regards,

Eduardo Tavares