The CEXT is a module that clips on to the C225 module to extend the number of zones by an additional 6. So it will change a standard 8 zone system to 14 zones.

To see where a CEXT is connected into a typical system click here




CEXT Module

The Zone port extension modules allow the C225 module to be extended from 8 ports zone ports to 14 zone ports for larger systems with more zones.

Zone damper ports

Connect the RJ12 (RJ11 on older systems) cables from the damper motors here. Start at zone 9 and connect sequential ports. ie 10,11,12......etc

Connection pins to C225 module

Connect the CEXT to C225 on this side. Ensure the pins are aligned with the female connector and take care when clipping modules together. To view assembled product please click on this link.

Connection ports to C325 AC unit modules

Connect the C325 AC unit module on this side




Zone Port Extension Module Specification


Model numbers


Power supply

From C225 connection

Casing material

Fire retardant ABS plastic

Operating Temperature

Up to 65oC

Communications protocols


Number of zones

9 to 14 (RJ11 or RJ12 connectors)

O/A Dimensions

Height  32 mm

Width   119 mm

Length  65 mm (When connected)


113 g






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