Symptom: The Pressure At The Tapping Point Is Temporarily Unusually High; Symptom: Tank Disinfection Function Is Not Completed Correctly (Ah-Error); Symptom: Boiler Abnormality Detection (Hj-11 Error); Symptom: Boiler/Hydrobox Combination Abnormality (Ua52 Error) - Daikin Altherma 08CA Installer's Reference Manual

13 Troubleshooting
Possible causes
Too much heat pump capacity is
used for heating domestic hot
water (applies only to
installations with a domestic hot
water tank)
13.3.7 Symptom: The pressure at the tapping
point is temporarily unusually high
Possible causes
Failing or blocked pressure relief
valve.
13.3.8 Symptom: Tank disinfection function is
NOT completed correctly (AH-error)
Possible causes
The disinfection function was
interrupted by domestic hot water
tapping
Large domestic hot water tapping
happened recently before the
programmed start-up of the
disinfection function
The disinfection operation was
stopped manually: with the user
interface displaying the DHW
home page and its user
permission level set to Installer,
the button was pressed
during disinfection operation.
Installer reference guide
96
Corrective action
Check and make sure that the
"space heating priority" settings
have been configured
appropriately:
▪ Make sure that the "space
heating priority status" has
been enabled. Go to [A.8] >
Installer settings > Overview
settings [5‑02]
▪ Increase the "space heating
priority temperature" to
activate backup heater
operation at a higher outdoor
temperature. Go to [A.8] >
Installer settings > Overview
settings [5‑03]
Corrective action
▪ Flush and clean the complete
tank including the piping
between pressure relief valve
and the cold water inlet.
▪ Replace the pressure relief
valve.
Corrective action
Program the start-up of the
disinfection function when the
coming 4 hours NO domestic hot
water tapping is expected.
When the Domestic hot water >
Type > Reheat or Reheat +
sched. is selected, it is
recommended to program the
start-up the disinfection function
at least 4 hours later than the last
expected large hot water tapping.
This start-up can be set by
installer settings (disinfection
function).
When the Domestic hot water >
Type > Scheduled only is
selected, it is recommended to
program a Storage eco 3 hours
before the scheduled start-up of
the disinfection function to
preheat the tank.
Do NOT press the button
while the disinfection function is
active.
13.3.9 Symptom: Boiler abnormality detection
(HJ-11 error)
Possible causes
Communication cable problem
Boiler error
13.3.10 Symptom: Boiler/hydrobox combination
abnormality (UA52 error)
Possible causes
Boiler/hydrobox mismatch
Incompatibility of software

13.3.11 Symptom: The burner does NOT ignite

Possible causes
Gas tap is closed.
Air in the gas tap.
Gas supply pressure too low.
No ignition.
No spark. Ignition unit on gas
valve faulty.
Gas/air adjustment NOT correctly
set.
Fan faulty.
Fan dirty.
Gas valve faulty.

13.3.12 Symptom: The burner ignites noisily

Possible causes
Gas supply pressure too high.
Incorrect ignition gap.
Gas/air adjustment NOT correctly
set.
Weak spark.
EVLQ05+08CAV3 + EHYHBH05AA + EHYHBH/X08AA +
Corrective action
Mount the communication cable
between the gas boiler and the
indoor unit properly.
Check the boiler display for error
information.
Corrective action
Make sure that the . setting is
the following for:
▪ 0=for EHYHBH05
EHYHBH08
▪ 1=for EHYHBX08
Update the boiler and hydrobox
software to the latest version.
Corrective action
Open the gas tap.
Remove air from the gas pipe.
Contact the gas supply company.
Replace the ignition electrode.
▪ Check the cabling.
▪ Check the spark plug cap.
▪ Replace the ignition unit.
Check the adjustment. See "To
check the carbon dioxide
setting" on page 82.
▪ Check the wiring.
▪ Check the fuse. If necessary,
replace the fan.
Clean the fan.
▪ Replace the gas valve.
▪ Re-adjust the gas valve, see
"To check the carbon dioxide
setting" on page 82.
Corrective action
The house pressure switch may
be faulty. Contact the gas
company.
▪ Replace the ignition pin.
▪ Check the ignition electrode
gap.
Check the setting. See "To check
the carbon dioxide setting" on
page 82.
Check the ignition gap.
Replace the ignition electrode.
Replace the ignition unit on the
gas valve.
EHYKOMB33AA
Daikin Altherma hybrid heat pump
4P355634-1C – 2018.06
+