Control Functionality; Automatic Mode; Backup & Rotate; Example - Procon MelCOMMS MINI Installation Manual

6. Control Functionality

6.1. Automatic Mode

When the switch on the front panel is set to 'Automatic' the MelCOMMS MINI will perform Backup & Rotate
functionality.
6.1.1. Backup & Rotate
A common installation scenario is a number of split systems that operate on a cyclical basis, with one unit on backup to
operate in case of failure. MelCOMMS MINI can handle Backup and Rotate functionality for between 2 and 8 indoor
units. On a periodic basis, typically every week, the operational units can be cycled to share the cooling load.
If the high temperature is exceeded by any unit while backup and rotate is active, all units are brought into operation. If
a fault is detected the next available unit will be brought into action or all available units will be switched ON depending
on the E.R. (Error Response) setting. The unit(s) will remain on until the next changeover cycle.

6.1.2. Example

Consider the following setup:
- Number of units = 4
- Number of units running = 2
- Max Temperature setpoint = 28ºC
- Rotation period = 1 day
- Error Response = Bring all units ON.
The following sequence of events show how the units are controlled when firstly a unit goes into fault and secondly
when a high temperature is detected: