Issue:
Describe the condenser fan staging logic for RTAC chillers
Resolution:
- The condenser fan staging logic is outlined as follows:
- Prior to the activation of either compressor, the microprocessor will monitor the outdoor ambient temperature sensor.
- Fans will be pre-staged before the compressor starts operating. The number of pre-staged fans will increase with higher outdoor temperatures.
- Once a compressor is activated, the microprocessor will oversee the condenser pressure and evaporator pressure transducers to maintain a 60 psid by controlling fan staging.
- As the differential pressure exceeds the desired 60 psid setpoint, additional fans will be activated.
- Upon the differential pressure dropping below 60 psid, the microprocessor will deactivate some of the fans.
- Ensure the accuracy of pressure transducer readings by installing a swivel T below the valve and comparing gauge pressure with the panel's indication.
Notes:
- Pre-stage fans on ambient temperature.
- Check to make sure that the pressure transducers are reading correctly by installing a swivel T under the valve and compare gauge pressure with what the panel is indicating.
Changes:
Other Question/Problem/Cause Statements:
- Why are all of the condenser fans on?
- How does the condenser fan logic work?
- What is the differential pressure the fans are supposed to control to?
- How do fans stage?
- Fan staging logic.
- All condenser fans stay on.
Facts:
- Air-Cooled Chiller (Pueblo) (RTAC)
Original HUB Document: DOC-89689
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.