STIEBEL ELTRON WWK 300 - Description of Functions; Operation Outside the Limits

1.4 Description of functions
Heat pump operation
This is the standard operating mode for DHW production, to which the limits of scope of the heat
pump apply ( s ee specification table, page 3 ) . Below are the heat up times the WWK300 requires
to heat water in the tank by 45°C for three different
ambient air temperatures.
If the heat pump was manually switched OFF an ON again after a power failure, the compressor will only re-start ( after
approx. 15 minutes ) when the pressure inside the refrigerant circuit has normalised again.
Electrical supplementary heater
You can accelerate the heating-up process with the electrical supplementary heater if the DHW
demand increases or if the WWK 300 has previously been switched OFF and you require hot water
as quickly as possible. For saving energy purposes, the electrical supplementary heater only heats
the top third of the cylinder capacity ( approx. 100 L ) . This takes about 2 hours.
1.5 Operation outside the limits of use ( b etween 4° C to 6°C )
Subject to relative humidity and the DHW temperature inside the cylinder, the evaporator begins to
ice up below a room temperature of 6
o
C. When the evaporator is covered in hoarfrost, the frost stat
N2 ( see wiring diagram ) shuts down the compressor while the fan continues to operate, thereby
defrosting the evaporator. The compressor starts again automatically after the defrosting process has
been completed and the heat pump operation continues.
The minimum temperature allowed for heat pump operation is +4°C. The evaporator is defrosted
upon demand at operating temperatures between +4
o
C and +6°C. This increases the heat-up time.
Room temperature higher than 35
° C
The heat pump will be switched OFF by safety equipment at room temperatures above approx.
35° C. It will re-start automatically after a brief cooling down period, but will be switched OFF again if
the room temperature is still higher than 35°C.
Space Humidity Cold Water Heat-up time COP
6
o
C 70% 15
o
C 11.5 h 3.3
15
o
C 70% 15
o
C 9.0 h 4.1
35
o
C 47% 15
o
C 6.4 h 5.1
5
1. OPERATING INSTRUCTIONS
cont..
Take appropriate steps to prevent the ambient
temperature rising above 35
o
C