Daikin Altherma EHVH04S18CB3V - Symptom: the Compressor Does NOT Start (Space Heating or Domestic Water Heating); Symptom: the Pump Is Making Noise (Cavitation); Symptom: the Pressure Relief Valve Opens; Symptom: the Water Pressure Relief Valve Leaks

12 Troubleshooting
Installer reference guide
79
ERLQ004~008CA + EHVH/X04+08S18+26CB
Daikin Altherma – Low temperature split
4P384973-1A – 2016.02
Possible causes Corrective action
The water flow is too low Check and make sure that:
▪ All shut-off valves of the water
circuit are completely open.
▪ The water filter is clean. Clean
if necessary.
▪ There is no air in the system.
Purge air if necessary. You
can purge air manually (see
"To perform a manual air
purge"on page74) or use the
automatic air purge function
(see "To perform an automatic
air purge"on page74).
▪ The water pressure is >1 bar.
▪ The expansion vessel is NOT
broken.
▪ The resistance in the water
circuit is NOT too high for the
pump (see "14.9 ESP
curve"on page108).
If the problem persists after you
have conducted all of the above
checks, contact your dealer. In
some cases, it is normal that the
unit decides to use a low water
flow.
The water volume in the
installation is too low
Make sure that the water volume
in the installation is above the
minimum required value (see
"6.4.3To check the water volume
and flow rate"on page26).
12.3.2 Symptom: The compressor does NOT
start (space heating or domestic water
heating)
Possible causes Corrective action
The unit must start up out of its
operation range (the water
temperature is too low)
If the water temperature is too
low, the unit uses the backup
heater to reach the minimum
water temperature first (15°C).
Check and make sure that:
▪ The power supply to the
backup heater is correctly
wired.
▪ The backup heater thermal
protector is NOT activated.
▪ The backup heater contactors
are NOT broken.
If the problem persists after you
have conducted all of the above
checks, contact your dealer.
The preferential kWh rate power
supply settings and electrical
connections do NOT match
This should match with the
connections as explained in
"6.5Preparing electrical
wiring"on page27 and "7.9.7To
connect the main power
supply"on page41.
The preferential kWh rate signal
was sent by the electricity
company
Wait for the power to return (2
hours max.).
12.3.3 Symptom: The pump is making noise
(cavitation)
Possible causes Corrective action
There is air in the system Purge air manually (see "To
perform a manual air purge"on
page74) or use the automatic air
purge function (see "To perform
an automatic air purge"on
page74).
The water pressure at the pump
inlet is too low
Check and make sure that:
▪ The water pressure is >1bar.
▪ The manometer is not broken.
▪ The expansion vessel is NOT
broken.
▪ The pre-pressure setting of the
expansion vessel is correct
(see "6.4.4 Changing the pre-
pressure of the expansion
vessel"on page26).
12.3.4 Symptom: The pressure relief valve opens
Possible causes Corrective action
The expansion vessel is broken Replace the expansion vessel.
The water volume in the
installation is too high
Make sure that the water volume
in the installation is below the
maximum allowed value (see
"6.4.3To check the water volume
and flow rate"on page26 and
"6.4.4Changing the pre-pressure
of the expansion vessel"on
page26).
The water circuit head is too high The water circuit head is the
difference in height between the
indoor unit and the highest point
of the water circuit. If the indoor
unit is located at the highest
point of the installation, the
installation height is considered
0m. The maximum water circuit
head is 10m.
Check the installation
requirements.
12.3.5 Symptom: The water pressure relief valve
leaks
Possible causes Corrective action
Dirt is blocking the water
pressure relief valve outlet
Check whether the pressure
relief valve works correctly by
turning the red knob on the valve
counterclockwise:
▪ If you do NOT hear a clacking
sound, contact your dealer.
▪ If the water keeps running out
of the unit, close both the
water inlet and outlet shut-off
valves first and then contact
your dealer.