Daikin ALTHERMA HT EKBUHAA6 V3, Service Manual

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External Backup Heater Kit ESIE09-08A
266 Appendix
6.7 Troubleshooting: General Symptoms
General heating
capacity shortage
(but no AA error
indication)
Possible causes Corrective action

BUH not operating: No symbol visible on the remote controller)
The heater kit is not activated. Check that the “heater kit operation status” field
setting [6-02] is turned on (1).
Operation conditions are not fullfilled 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”.

BUH not operating: Symbol visible on the remote controller
There is not enough water flow. 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.
There is air in the system. 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.
Broken contactor. Check contactors and relays by use of an ohmmeter.