Introduction; Condensing Unit Control System Overview - Johnson Controls System 450 Series Technical Bulletin

Introduction

The C450CCU condensing unit control module is a custom System 450 control module. The
condensing unit control module has relay outputs and firmware that provide temperature
control for refrigerated spaces. Additional C450CCU functions include passive (off-cycle) or active
electric heat defrost control, evaporator fan speed control, and optional pump down control.
Use the condensing unit control module with a C450YNN power module and a C450SCN relay
output expansion module to provide complete temperature control for small and medium-sized
refrigerated spaces. You can add additional C450SCN relay output expansion modules for alarm
functions.
Important: Use the System 450 Series C450CCU condensing unit control module only as an
operating control. To prevent personal injury or property damage to the controlled equipment,
other property from failure or malfunction of the condensing unit control module, it is necessary
to design additional precautions into the control system. Incorporate and maintain other
devices, such as supervisory or alarm systems or safety or limit controls, intended to warn of or
protect against failure or malfunction of the condensing unit control module.
Important: Utiliser ce System 450 Series C450CCU condensing unit control module uniquement
en tant que dispositif de contrôle de fonctionnement. Lorsqu'une défaillance ou un
dysfonctionnement du régulateur risque de provoquer des blessures ou d'endommager
l'équipement contrôlé ou un autre équipement, la conception du système de contrôle doit
intégrer des dispositifs de protection supplémentaires. Veiller dans ce cas à intégrer de façon
permanente d'autres dispositifs, tels que des systèmes de supervision ou d'alarme, ou des
dispositifs de sécurité ou de limitation, ayant une fonction d'avertissement ou de protection en
cas de défaillance ou de dysfonctionnement du régulateur.
See Related documentation
controls.

Condensing unit control system overview

The condensing unit control module provides refrigeration condensing unit control and has the
following features:
• Temperature control of a refrigerated space
• Defrost control
- Passive, off-cycle defrost control for medium-temperature applications
- Active, electric heat defrost control for low-temperature applications
- Optional defrost termination sensor or defrost termination switch
- One to eight daily scheduled defrost cycle times
- Manual activation or termination of a defrost cycle
- Set drip time so that water drips off the evaporator at the end of an electric defrost cycle,
before turning on evaporator fans and starting the compressor.
- Set the evaporator fan delay time. This is the amount of time following the defrost cycle
that the evaporator fans remain off.
• Evaporator fan control
- Control single or two-speed evaporator fans.
System 450 Series C450CCU Condensing Unit Control System Technical Bulletin
for more resources relating to the System 450 series of modular
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