Chilled Water Plant Loop - Pump Error

Mara · August 24, 2026, 1:23pm

Hi all,

I’m running into a reproducible bug with Ironbug’s ChilledWaterLoop/CWLoop component and wanted to check whether this is known, and whether there’s a canvas-side fix I’m missing.

Setup:

Ironbug 1.21.0.0 on Rhino/Grasshopper, EnergyPlus 25.1.0
ChilledWaterLoop (CWLoop) component, wired with:
- Supply: PlantComponent:TemperatureSource (constant 13°C, standing in for a black-box ground source) + a pump, on the supply branch
- Demand: three Coil:Cooling:Water branches in parallel

The bug:

** Severe ** Invalid [pump] component found on equipment list.
Pumps are not allowed on equipment lists.
Problem component name = PUMP CONSTANT SPEED 1
** Fatal ** InitLoadDistribution: Fatal error caused by previous severe error(s).

What I’ve tried (all reproduce the identical error):

Switching the pump between Pump:ConstantSpeed and Pump:VariableSpeed — same fatal error either way, just with the corresponding pump type named in the equipment list.
Changing the canvas wiring topology — merging the pump and equipment into one wire vs. feeding them into supply as separate/parallel connections (matching the pattern used in Ironbug’s own bundled “Chilled water loop” example file) — no change in behavior.
Switching from ChilledWaterLoop/CWLoop to the generic PlantLoop component then the pump error disappear but i get:
** Severe ** [PlantEquipmentOperation:CoolingLoad][Plant Equipment Operation Cooling Load 1] - Missing required property ‘load_range_1_lower_limit’.
** Severe ** [PlantEquipmentOperation:CoolingLoad][Plant Equipment Operation Cooling Load 1] - Missing required property ‘load_range_1_upper_limit’.
** Fatal ** Errors occurred on processing input file. Preceding condition(s) cause termination.
…Summary of Errors that led to program termination:
… Reference severe error count=2
… Last severe error=[PlantEquipmentOperation:CoolingLoad][Plant Equipment Operation Cooling Load 1] - Missing required property ‘load_range_1_upper_limit’.

Question for the community: is this a known issue? How could i solve it?

Flirsch_v11_HVAC_variants_withcoolingcoil.gh (1.0 MB)

Thanks!