Regarding the DOAS controller list, I agree, it should not be required unless there is a water coil in the list. I think the controller presence should be testing for the presence of a water coil.

The defect file DOAS OA System object has a blank controller list name so why is the equipment list name reported? The message is using AlphaArray(1) which gets overwritten when the equipment list gets processed prior to checking for the controller list.

AirLoopHVAC:DedicatedOutdoorAirSystem,
  DOAS loop,               !- Name
  DOAS loop AHU,           !- AirLoopHVAC:OutdoorAirSystem Name

AirLoopHVAC:OutdoorAirSystem,
  DOAS loop AHU,           !- Name
  ,                        !- Controller List Name
  DOAS loop Outdoor air Equipment List;  !- Outdoor Air Equipment List Name

The DOAS code requires the controller list and should instead check for a water coil here in this else? or move this message elsewhere? The air loop checks for a controller while processing the equipment list in SimAirServingZones::GetAirPathData around line 1340 here. Same for the OA System just below the code in SimAirServingZones here. Notice that AlphArray gets overwritten in the call for the equipment list. The DOAS data should be kept separate with this calling structure.

    if (!lAlphaBlanks(3)) {
        int ListNum = state.dataInputProcessing->inputProcessor->getObjectItemNum(
            state, CurrentModuleObjects[static_cast<int>(CMO::AirLoopEqList)], OASys.ComponentListName);
        if (ListNum > 0) {
            state.dataInputProcessing->inputProcessor->getObjectItem(
                state, CurrentModuleObjects[static_cast<int>(CMO::AirLoopEqList)], ListNum, AlphArray, NumAlphas, NumArray, NumNums, IOStat);

    if (!lAlphaBlanks(2)) {
    } else {
        if (state.dataInputProcessing->inputProcessor->getNumObjectsFound(state, "AirLoopHVAC:DedicatedOutdoorAirSystem") == 0) {
            ShowSevereError(state,
                            format("{} = \"{}\" invalid {} is blank and must be entered.", CurrentModuleObject, AlphArray(1), cAlphaFields(2)));
            ErrorsFound = true;
        } else {
            ShowWarningError(state,
                             format("{} = \"{}\": blank {} must be used with AirLoopHVAC:DedicatedOutdoorAirSystem.",
                                    CurrentModuleObject,
                                    AlphArray(1),
                                    cAlphaFields(2)));
        }
    }

SimAirServingZones already loops through all OA Systems so maybe @mjwitte is correct and these messages for missing DOAS controller can be deleted. The controller water coil connection will be tested in SimAirServingZones. i.e., just delete the else for if (!lAlphaBlanks(2)).

I think I'm following this. So, @rraustad, would you say: yes, you are on board with the suggestion of @mjwitte to get rid of the code:

    } else {
        ShowWarningError(state,
                         format("{} = \"{}\": blank {} must be used with AirLoopHVAC:DedicatedOutdoorAirSystem.",
                                CurrentModuleObject,
                                AlphArray(1),
                                cAlphaFields(2)));

as part of this work? If yes, then I will delete it and make another commit. If no, I will hold until there is agreement.

Thanks to you both for your feedback on this!

@RKStrand yes I am on board with deleting this else. I would ask you test SmallOffice_CentralDOAS, by removing the controller list name from the AirLoopHVAC:OutdoorAirSystem, to make sure the correct warning is reported.

@rraustad @mjwitte After removing the else code as described above and running SmallOffice_CentralDOAS with the controller list names removed from one of the AirLoopHVAC:OutdoorAirSystem definitions, I get the following error messages:

** Severe ** AirLoopHVAC:OutdoorAirSystem = "PSZ-AC:1_OA" invalid Controller List Name = " not found.
** Fatal ** getAirLoopHVACDOAS: Previous errors cause termination.

Is this what was expected/desire? If the answer is yes, I will commit this change. If no, please advise as to what you would like done. Thanks!

Yes, that's the correct type of warning I was looking for. But the test would be for the DOAS system where you removed the check.

AirLoopHVAC:DedicatedOutdoorAirSystem,
  AirLoopHVAC DOAS,        !- Name
  AirLoopDOAS OA system,   !- AirLoopHVAC:OutdoorAirSystem Name

Try removing OA Sys 1 Controllers here and see if you get the same message.

AirLoopHVAC:OutdoorAirSystem,
  AirLoopDOAS OA system,   !- Name
  OA Sys 1 Controllers,    !- Controller List Name
  OA Sys 1 Equipment;      !- Outdoor Air Equipment List Name

@rraustad 😳 Either I needed to be wearing my glasses or it was a little too early in the morning and I wasn't firing on all cylinders, because clearly I missed that I was changing the wrong object. My bad--sorry about that and for wasting your time. Now, I believe I got rid of the correct controller list. Here is the error message that was produced:

** Severe ** AirLoopHVAC:ControllerList="OA SYS 1 CONTROLLERS" is not referenced on a AirLoopHVAC or AirLoopHVAC:OutdoorAirSystem object.
************* No node connection errors were found.
** Fatal ** Previous Conditions cause program termination.

Is this what you were looking for as far as an error message produced by E+?

That's the same dumb warning that requires a controller list and fatals out. A controller is required only if there is a water coil. Do we not have any example files with outdoor air systems that don't use a water coil?

    //  Now check AirLoopHVAC and AirLoopHVAC:OutdoorAirSystem
    int Found = 0;
    if (state.dataAirLoop->NumOASystems > 0) {
        Found = Util::FindItemInList(ControllerListName, state.dataAirLoop->OutsideAirSys, &OutsideAirSysProps::ControllerListName);
        if (Found > 0) {
            ++Count;
        }
    }

    if (Count == 0) {
        ShowSevereError(state,
                        format("{}=\"{}\" is not referenced on a AirLoopHVAC or AirLoopHVAC:OutdoorAirSystem object.",
                               CurrentModuleObject,
                               ControllerListName));
        ErrFound = true;

Not exactly, that error is because the controller list is present but never referenced. Try delete the controller list and leaving the controller list name blank.

No problem. Here is what happened when I deleted the controller list and left the controller list name blank:

** Severe ** HVACControllers: GetControllerInput: Controller:WaterCoil="OA HC CONTROLLER 1" not found on any AirLoopHVAC:ControllerList.
** Severe ** HVACControllers: GetControllerInput: Controller:WaterCoil="OA CC CONTROLLER 1" not found on any AirLoopHVAC:ControllerList.
** Fatal ** HVACControllers: GetControllerInput: Errors found in getting Controller:WaterCoil input.

Not sure why the one error message shows up twice.

Ok, well, now we have dangling controllers, so we need to also delete the controller objects. Then you should have covered all of the bases.

As above but now with the controller objects deleted. Here are the resulting error messages:

** Severe ** GetAirPathData: AirLoopHVAC="OA HEATING COIL 1", invalid actuator.
** ~~~ ** ...this coil requires a water coil controller and the inlet node of a water coil must also be an actuator node of a water coil controller.
** Severe ** GetAirPathData: AirLoopHVAC="OA COOLING COIL 1", invalid actuator.
** ~~~ ** ...this coil requires a water coil controller and the inlet node of a water coil must also be an actuator node of a water coil controller.
** Fatal ** GetAirPathData: Errors found retrieving input for AirLoopHVAC.

And I realized it wasn't a double error message previously but rather one was "CC" and one was "HC".

CI is all green. Merging.