STIEBEL ELTRON Accelera 300 - Manual (Page 11)

OPERATION
WATER HEATER DESCRIPTION
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WWW.STIEBEL-ELTRON-USA.COM ACCELERA® 300 HEAT PUMP WATER HEATER | 11
4. Water heater description
This water heater is an automatic hot water generator with approx.
303 l (80 gallon) capacity. The hot water temperature is factory
set to 60 °C (140 °F).
After opening a hot water faucet, the hot water is pushed out of
the water heater by the incoming cold water.
This water heater works like an air conditioner but does not need
to be vented. The water heater extracts heat from the ambient air
to heat the water. The demand for electrical energy and the heat-
up time depend on the ambient air temperature and humidity.
When installing the water heater inside, the space where it is
installed will be cooled down during the operation by 1 to 3 °C
(2 to 6 °F).
The water heater also extracts moisture from the air that creates
condensate, which must be drained off. For this purpose, a
condensate drain is integrated in the water heater. This is where
you can connect a hose to a drain.
To protect the steel tank against corrosion, the interior is coated
with a special enamel and is equipped with a replaceable sacrificial
anode.
Heat pump function:
A sealed circuit inside the water heater contains R134A refrigerant
(see "Specification/data table"); this does not deplete ozone, is
non-flammable, and evaporates at low temperatures.
In the evaporator, where heat is extracted from the outside air,
the refrigerant changes from its liquid into its gaseous state. A
compressor draws in the gas in and compresses it. The increase
in pressure raises the refrigerant temperature and heats the water
tank.
This process requires electrical energy. The energy (motor heat)
is not lost, but reaches the condenser downstream together with
the compressed refrigerant. Here, the gas transfers heat to the
water tank. An expansion valve then reduces the pressure and
the process starts again.
4.1 Function description
4.1.1 Heat pump operation
The heat pump unit located on top of the water heater extracts
heating energy from the ambient air.
If the water heater was separated from the power
supply during operation, the compressor will only
restart if the pressure inside the refrigerant circuit has been
balanced. Pressure balance can only be created after waiting
15 minutes.
4.1.2 Booster heater
Primarily, the water inside the tank is heated by the heat pump.
When there is a higher hot water demand or when the water heater
was switched OFF and you require hot water quickly, the integral
booster heater will turn on. To save energy, the booster heater
only heats the top third of the tank (approx. 102 l (27 gallons)).
A thermostat switches the booster heater on if the water
temperature inside the tank falls below 45 °C (112 °F). A thermostat
switches the booster heater off if the water temperature inside the
tank exceeds 60 °C (140 °F).
4.1.3 Defrosting
The lower limit of use of the water heater is permanently set to
6 °C (42 °F). It is possible that at this limit, the evaporator will be
coated in frost. This is subject to the air temperature and humidity
level, particularly at low hot water temperatures.
The compressor will be switched off as soon as the evaporation
temperature falls below -7 °C (20 °F) for any length of time. When
the temperature at the evaporator fins rises above 3 °C (38 °F), the
compressor starts again, and the hot water heating continues. The
fan continues to run during defrosting.
5. Operation
You do not have to make any adjustments. The water heater
is therefore not equipped with any controls. The hot water
temperature is factory set to 60 °C (140 °F).
Should you wish to operate with different settings, contact your
local licensed installer.
WARNING Scalding
The water is heated inside the water tank to
60 °C (140 °F). There is a risk of scalding at outlet
temperatures in excess of 42 °C (108 °F).
Ensure that outflowing water does not directly contact
your body.
5.1 Initial start-up by a licensed installer
Initial start-up should be done by a licensed installer.
5.2 Starting and stopping
The water heater is not equipped with an ON/OFF switch. If a
power plug was fitted during installation, you can disconnect
the water heater from the power supply by pulling that plug.
Alternatively, you can terminate the water heater operation by
tripping the circuit breaker.
5.3 Emergency stop
In case of emergency, carry out the following steps:
» Isolate the power supply by tripping the circuit breaker or by
pulling the power plug.
» Shut off the cold water inlet.
6. Maintenance and care
A damp cloth is sufficient for cleaning the exterior of the water
heater. Never use abrasive or corrosive cleaning agents. Do not
hose down the water heater.
» Monthly, check that the condensate drain is clear.
» Monthly, carry out a visual inspection of the condensate
pan drain (in the top of the water heater; see the following
diagram). Look through the air intake grille at the front of the
water heater. If required, notify your local licensed installer
who will remove any contamination.