Revision history [back]

Hello, As this issue has been discussed for years I hope someone can help me to figure this out. Unitary system cooling coils cause condenser water loop plant temperatures to get too hot and cause system to fail. * Fatal * CheckForRunawayPlantTemps: Simulation terminated because of run away plant temperatures, too hot As it was discussed earlier not to have multiple objects in unitary object; the unitarysyetm object only consists of Coil:Cooling:WaterToAirHeatPump:EquationFit and fan is modeled separately in the downstream of the unitary object. A mixed air setpoint manager is added for the unitary object. Condenser water plant loop has a constant speed pump which has a continuous control type as intermittent control causes pump outlet temperature to be off the ranges. I tried adding outdoor air pipe to the supply branch outlet node, adding bypass branch to the supply loop or changing setpoint manager types for the unitary object but nothing could solve this issue. I will appreciate any feedback.

Thank you Elvin

Hello, As this This issue has been discussed for years I hope someone can help me to figure this out. Unitary system cooling coils cause condenser water loop plant temperatures to get too hot and cause system to fail. *

**  Fatal  * ** CheckForRunawayPlantTemps: Simulation terminated because of run away plant temperatures, too hot

As it was discussed earlier not to have multiple objects in unitary object; the unitarysyetm object here is my current setup for the unitary system object:

• only consists of Coil:Cooling:WaterToAirHeatPump:EquationFit and Coil:Cooling:WaterToAirHeatPump:EquationFit
• fan is modeled separately in the downstream of the unitary object. A object
• mixed air setpoint manager is added for the unitary object. Condenser object
• condenser water plant loop has a constant speed pump which has a continuous control type as intermittent control causes control

The pump outlet temperature to be off the ranges. is causing the fatal error. I tried adding outdoor air pipe to the supply branch outlet node, adding bypass branch to the supply loop or changing setpoint manager types for the unitary object but nothing could solve this issue. I will appreciate any feedback. feedback.

This issue has been discussed for years I hope someone can help me to figure this out. Unitary system cooling coils cause condenser water loop plant temperatures to get too hot and cause system to fail.

**  Fatal  ** CheckForRunawayPlantTemps: Simulation terminated because of run away plant temperatures, too hot

As it was discussed earlier not to have multiple objects in unitary object here is my current setup for the unitary system object:

• only consists of Coil:Cooling:WaterToAirHeatPump:EquationFit
• fan is modeled separately downstream of the unitary object
• mixed air setpoint manager is added for the unitary object
• condenser water plant loop has a constant speed pump which has a continuous control type as intermittent control

The pump outlet temperature is causing the fatal error. I tried adding outdoor air pipe to the supply branch outlet node, adding bypass branch to the supply loop or changing setpoint manager types for the unitary object but nothing could solve this issue. I will appreciate any feedback.