To Drain The Domestic Hot Water Tank - Daikin Altherma EHVH08SU18CB6W Installer's Reference Manual

To make sure this water originates from the tank, check after a tank
heat up cycle.
It is recommended to do this maintenance more frequently.
Discharge piping
Check whether the discharge piping is positioned appropriately to
drain the water. See "7.8.4 To connect the water piping" on page 39
and "7.8.5 To connect the pressure relief valve to the drain" on
page 41.
Pressure relief valve of the domestic hot water tank
Check for correct operation of the pressure relief valve of the
domestic hot water tank. To ensure free water flow through the
discharge pipe, manually operate it by turning its knob left.
Booster heater of the domestic hot water tank
It is recommended to remove lime buildup on the booster heater to
extend its life span, especially in regions with hard water. To do so,
drain the domestic hot water tank, remove the booster heater from
the domestic hot water tank and immerse in a bucket (or similar) with
lime-removing product for 24 hours.
Switch box
▪ Carry out a thorough visual inspection of the switch box and look
for obvious defects such as loose connections or defective wiring.
▪ Using an ohmmeter, check if contactors K1M, K2M, K3M and K5M
(depending on your installation) operate correctly. All contacts of
these contactors must be in open position when the power is
turned OFF.
WARNING
If the internal wiring is damaged, it has to be replaced by
the manufacturer, its service agent or similarly qualified
persons.
Descaling
Depending on water quality and set temperature, scale can deposit
on the heat exchanger inside the domestic hot water tank and can
restrict heat transfer. For this reason, descaling of the heat
exchanger may be required at certain intervals.
Chemical disinfection
If the applicable legislation requires a chemical disinfection in
specific situations, involving the domestic hot water tank, please be
aware that the domestic hot water tank is a stainless steel cylinder
containing an electronic anode. We recommend to use a non-
chloride based disinfectant approved for use with water intended for
human consumption.
NOTICE
When using means for descaling or chemical disinfection,
it must be ensured that the water quality remains compliant
with EU directive 98/83 EC.
Anode
No maintenance or replacement required.
Pressure reducing valve of the domestic hot water tank kit
Depending on local water conditions, annual inspection of the
integral line strainer, pressure reducing valve cartridge, and seating
may be necessary.
▪ Unscrew the retaining nut of the valve. The complete operating
mechanism, including the strainer, can be removed.
▪ Clean the filter mesh and cartridge under running water.
▪ Replace cartridge, ensuring that the strainer is correctly located,
and reassemble the unit.
ERLQ004~008CA + EHVH04+08SU18+26CB6W
Daikin Altherma – Low temperature split
4P449978-1B – 2018.07
11 Maintenance and service
Pressure relief valve of the domestic hot water tank kit
Check for correct operation of the pressure relief valve. To ensure
free water flow through the discharge pipe, manually operate it by
turning its knob left. Water may be very hot!
Checkpoints are:
▪ The water flow coming from the relief valve is high enough, no
blockage of the valve or in between piping is suspected.
▪ Dirty water coming out of the relief valve:
▪ open the valve until the discharged water does not contain dirt
anymore
▪ flush and clean the complete tank, including the piping between
the relief valve and cold water inlet.
To make sure this water originates from the tank, check after a tank
heat up cycle. It is recommended to do this maintenance more
frequently.
Depending on local water conditions, annual inspection of the
pressure relief valve cartridge and seating may be necessary.
▪ Unscrew the pressure relief headwork from the valve body.
▪ Clean the valve seat face and seating. Do NOT scratch or
damage them.
▪ Refit in reverse order. Do NOT overtighten.
11.4.1

To drain the domestic hot water tank

Prerequisite: Turn OFF the unit via the user interface.
Prerequisite: Turn OFF the respective circuit breaker.
Prerequisite: Close the cold water supply.
1 Open the front panel.
2 Remove the 2 screws, unhook and put the switch box aside.
3 The drain hose is located at the right side of the unit. Cut the tie
wraps or tape and bring the flexible drain hose forward.
a
a Drain hose
INFORMATION
To drain the tank, all the hot water tapping points need to
be opened to allow air to enter the system.
4 Open the drain valve.
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