Symptom: The Pump Is Making Noise (Cavitation); Symptom: The Pressure Relief Valve Opens; Symptom: The Water Pressure Relief Valve Leaks; Symptom: The Space Is Not Sufficiently Heated At Low Outdoor Temperatures - Daikin Altherma EHVH08SU18CB6W Installer's Reference Manual

12.3.3 Symptom: The pump is making noise
(cavitation)
Possible causes
There is air in the system
The water pressure at the pump
inlet is too low
12.3.4

Symptom: The pressure relief valve opens

Possible causes
The expansion vessel is broken
The water volume in the
installation is too high
The water circuit head is too high The water circuit head is the
12.3.5 Symptom: The water pressure relief valve
leaks
Possible causes
Dirt is blocking the water
pressure relief valve outlet
ERLQ004~008CA + EHVH04+08SU18+26CB6W
Daikin Altherma – Low temperature split
4P449978-1B – 2018.07
Corrective action
Purge air manually (see "To
perform a manual air purge" on
page 75) or use the automatic air
purge function (see "To perform
an automatic air purge" on
page 75).
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 28).
Corrective action
Replace the expansion vessel.
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 27 and
"6.4.4 Changing the pre-pressure
of the expansion vessel" on
page 28).
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.
Corrective action
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.
12.3.6 Symptom: The space is NOT sufficiently
heated at low outdoor temperatures
Possible causes
The backup heater operation is
not activated
The backup heater equilibrium
temperature has not been
configured correctly
There is air in the system.
Too much heat pump capacity is
used for heating domestic hot
water
12.3.7 Symptom: The pressure at the tapping
point is temporarily unusually high
Possible causes
Failing or blocked pressure relief
valve.
12 Troubleshooting
Corrective action
Check and make sure that:
▪ The backup heater operation
mode is enabled. Go to:
▪ [A.5.1.1] > Installer settings
> Heat sources > Backup
heater > Operation mode
[4‑00]
▪ The backup heater overcurrent
fuse has not been turned off. If
it has, check the fuse and turn
it back on.
▪ The thermal protector of the
backup heater has not been
activated. If it has, check the
following, and then press the
reset button in the switch box:
▪ The water pressure
▪ Whether there is air in the
system
▪ The air purge operation
Increase the "equilibrium
temperature" to activate the
backup heater operation at a
higher outdoor temperature. Go
to:
▪ [A.5.1.4] > Installer settings >
Heat sources > Backup heater
> Equilibrium temp. OR
▪ [A.8] > Installer settings >
Overview settings [5‑01]
Purge air manually or
automatically. See the air purge
function in the "Commissioning"
chapter.
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.
Installer reference guide
81