OpenStudio error in Four Pipe Induction ATU: Induced Air Inlet Node Name is blank

I'm up against a recurring error very similar to the one described here.

The issue is a blank field for the Induced Air input field of a Four Pipe Induction Terminal supplied by Air Handling Unit 1. The interesting thing here is that every time I add a new terminal unit in a new zone the error seems to move to another (the new) terminal unit.

** Severe  ** IP: IDF line~7462 Error detected in Object=AIRTERMINAL:SINGLEDUCT:CONSTANTVOLUME:FOURPIPEINDUCTION, name=THB.08
**   ~~~   ** Field [Induced Air Inlet Node Name] is required but was blank

*************   7457   THB.08,                                 !- Name
*************   7458   ,                                       !- Availability Schedule Name
*************   7459   0.48,                                   !- Maximum Total Air Flow Rate {m3/s}
*************   7460   2.5,                                    !- Induction Ratio
*************   7461   Node 622,                               !- Supply Air Inlet Node Name
*************   7462   ,                                       !- Induced Air Inlet Node Name

I tried changing the type of analysis to detailed analysis as mentioned here, but that didn't make any difference.

In addition, the simulation ran before, but once I added additional ZoneExhaust and Ventilation:DesignFlowRate objects it started failing, maybe that has something to do with it.

Here is a link to the OpenStudio file.

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147

Chris

asked 2016-07-19 04:03:43 -0500

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__AmirRoth__

updated 2018-08-25 18:29:09 -0500

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Please refrain from creating new tags (blank-field in this case)

Julien Marrec (2016-07-19 04:39:53 -0500) edit

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This is definitely an OpenStudio problem, you should open an issue on Github

My two cents:

You have correctly identified that when you add a new one, the problem seems to move around. Well, partially. If you click on the splitter, and add a new zone, behind the scene the last ATU (Let's call it ATU-1) seems to be cloned to add this new thermal zone with a new ATU (let's call it ATU-1bis), and something seems amiss in the sense that the it reset the inducedAirInletNode of this ATU-1.
If you're looking for a quick work around, drop the thermal zone first, then add a Four Pipe Induction ATU to the inlet node of the zone. This works fine (the addToNode method works)
The initial design choice is questionable to me. It seems that the induced air inlet node is set during the call to the addToNode method (see source code here). I think it would make more sense to set the inducedAirInletNode during the forward translation, and to completely hide the inducedAirInletNode property in the API as well (it's not visible in the OS App but there's a getter (no setter) in the API).