Troubleshooting: General Symptoms - Daikin ALTHERMA HT Service Manual

External Backup Heater Kit
7.7

Troubleshooting: General Symptoms

General heating
capacity shortage
 BUH not operating: No symbol visible on the remote controller)
(but no AA error
The heater kit is not activated.
indication)
Operation conditions are not fullfilled
 BUH not operating: Symbol visible on the remote controller
There is not enough water flow.
There is air in the system.
Broken contactor.
254
Possible causes Corrective action
Check that the "heater kit operation status" field
setting [6-02] is turned on (1).
Check if system has low ESP. Pump speed can
be too low due to low ESP (<~2500 rpm).
Change minimum required pump speed by
changing E-03 to "0".
Check K1A-relay. Upper light green indicates the
relay is powered and that flow > 9l/min. Check for
water blockage in the system and filters.
Check K1A-relay. If flow is > 9 l/min for > 5
seconds consecutive, lower orange light lights up
and enables BUH operation.
If lower orange light does not light up, purge the
air out of the system.
Check contactors and relays by use of an
ohmmeter.
ESIE09-08B
Appendix