H/C changeover relay and fault status messages - Basic Documentation - RMK770-1

Communication via the KNX bus

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Air conditioning controller
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Basic Documentation
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Heating/cooling ch'over relay

If, instead of being transmitted over the bus, the H/C changeover signal is provided at a relay output, e.g. for switch control of a valve, or forwarding to a non-communicating device, the H/C changeover relay can be configured accordingly. See the notes on connecting the primary controller to the changeover valve.


Main menu > Commissioning > Extra configuration > Heating/cooling ch'over

Operating line Range Factory setting
Heating/cooling ch'over relay ----, N.Q1, N.Q2,…/ ----

Current contact position

The current contact position (status) of the changeover relay can be displayed via the Service level.

Main menu > Heating/cooling ch'over

Operating line Current contact position (status)
Heating/cooling ch'over relay Open (Off) Cooling / Closed (On): Heating

Fault status messages

H/C changeover signal failure

In a 2-pipe system without H/C changeover signal on the KNX bus, the controller continues to use the last received value. If the signal never existed, "Heating" is used as default value.

Fault status message 5801

No. Text Effect
5801 H/C changeover signal failure Non-urgent message; no acknowledgement required.

> 1 H/C changeover signal

If the "H/C changeover" in a 2-pipe system is configured so that it is initiated by calendar or operating mode selector, and if a changeover signal is received in one of the zones from another device, message ">1 heat/cool changeover signal" is transmitted.

Fault status message 5802

No. Text Effect
5802 >1 heat/cool changeover signal Non-urgent message; must be acknowledged.