Control Principle; Defrost Method; Dimensions Of Outdoor Unit Model Cs3400Iaws; Or-S - Bosch Compress 3400i AWS Installation Manual

Product description
3.6

Control principle

The control of the system is based on the heat demand of the building,
changing the compressor output and/or by switching on the integrated/
external auxiliary heater via the indoor unit. The user interface controls
the outdoor unit according to the heating curve that has been set. If the
outdoor unit is unable to meet the heat energy demand of the building on
its own, the indoor unit automatically start the auxiliary heater which,
together with the outdoor unit, generates the required temperature in
the building and in the DHW cylinder if necessary.
Heating and DHW mode when the outdoor unit is deactivated
When the outdoor temperature is less than –20 °C or exceeds 45 °C
(adjustable), the outdoor unit is automatically turned off and is unable to
produce any heat. In this case, the integrated/external auxiliary heater of
the indoor unit adopts the heating and DHW mode.
3.8 Dimensions of outdoor unit model CS3400iAWS 4 OR-S
341
Fig. 2 Dimensions of outdoor unit CS3400iAWS 4 OR-S
[1] Liquid side service valve
[2] Gas side service valve
[3] Feet for anchorage
6
902
976
609
3.7

Defrost method

The principle of defrosting in the outdoor unit is known as hot gas
defrosting. During defrosting, the flow in the refrigerant circuit is
reversed by means of an electrically-controlled four-way valve.The
compressed gas from the compressor is fed into the top of the
evaporator, causing the ice on the outside to melt. During this process,
the water in the heating system is slightly cooled. The time required for
defrosting depends on the amount of ice and the outdoor temperature.
The base of the casing below the evaporator of the outdoor unit serves
as a drip pan which accumulates condensation and ice.
We recommend installing heating cable for the condensate tray and
drain outlet (accessory for systematic removal of condensate). The
power supply of the heating cable is supplied by the indoor unit, which
will be activated during defrost operation.
705
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Compress 3400i AWS – 6721825369 (2021/11)
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0010036139-001