Louvre Flow configuration

[mark.silcock]

Hoping someone can clear this up for me as I have been scratching my head for a couple of hours now trying different configurations to get what I am after.

Pretty basic set up with some extract grilles connected to an inline fan which discharges out an external louvre.

As you can see the system inspector works so in theory everything is connected correctly. The problem I am having is when it comes to scheduling the system is double counting the external louvre flow rate and in the case above is reporting the fan is doing 1418 l/s not 709 l/s.

The way I have the connectors at the moment is E3 grille is set to preset and out, the intake on the fan is set to calculated and in, the outlet of the fan is set to preset and out, then the external louvre (which is an air terminal) is set to calculated and in. They are all using shared parameters.

Here is the system browser for the E10.

Should the louvre be something other than an air terminal? Should the fan connectors be linked or unlinked?

Looking forward to reading your responses 🙂

Cheers
MS

[Jrobker]

Your exhaust terminal E3 needs to be

Preset

Out

Exhaust air

Specific Loss

The connection going into the fan neeeds to be

Calculated

In

Exhaust Air

Specific Loss

The connection going out of the fan neeeds to be

Preset

Out

Exhaust Air

Not Defined

Do not link connectors

Which looks like you have that correct.

I think the problem is with the louver. You don't want a closed system. You need an open end. Check the direction of air flow. I believe that one should be 

Calculated

In

Hope that gets you closer.

[mark.silcock]

Thanks but the only way I could get the fan not to double up is to have two different systems. So return from the grille to the fan then extract from the fan to the louvre. But that does still give 2 values on the fan, the right flow rate just for both the differnt systems.

[mark.silcock]

I notice the post has been escalated, what does that mean?

[Jrobker]

It means you have advanced support. The factory is looking at it.

[mark.silcock · Accepted solution]

Here's what I got back from one of the MEP technicians:

Looking at the fan family, it appears its not setup the same way as the out of the box fans.

Your connectors are as follows:

Calculated
In
Exhaust
Specific Loss

Preset
Out
Exhaust
Not Defined

Also, the connectors are not linked.

If you look at Centrifugal Fan – inline – Tubular both connectors are as follows and they are linked and display the flow information correctly:

Calculated
Bidirectional
Global
Not Defined

The global system classification allows the fan to take on the system classification and name of the ducts it’s connected to. Your issue seems to be with setting the system classification to Exhaust. This causes Revit to sum the flow on the connectors in the fan instead of just passing it through.

[mark.silcock]

Now that was different to a couple of guides I had been looking at regarding connectors, seems there is some confusion out there. Anyway it seems to work with the suggested settings.