Defrosting; Defrosting Process - Viessmann EVO-COOL Series Installation And Operating Instructions Manual

GB
6.

Defrosting

6.1

Defrosting process

When the defrost function activates, the compressor and the
fan are switched off and the heater for the defrost water hose
is switched on.
Once the defrost water hose lead time has passed, the com-
pressor switches on and the bypass valve opens. The heater for
the defrost water hose continues running during this process.
The compressor remains running until the set defrost tempera-
ture is reached in the evaporator unit or the set maximum de-
frost period has passed. The maximum defrost period should
usually be set as a longer period rather than shorter one so
that defrosting occurs in full. The correct position and thermal
contact of the sensor in the evaporator unit must be checked
during maintenance (see figure).
The sensor is inserted diagonally downwards from the left
between the 9th and 10th fins and the 1st and 2nd sensor tube
at a depth of 34 mm.
If the sensor is positioned against a tube that is close to the
inflow during the defrosting process, defrosting does not
complete fully. The sensor reaches the set defrost temperature
prematurely and the control unit terminates the defrosting
process. The ice is simply melted and sinks to the bottom. This
results in a block of ice on the lower edge of the evaporator,
which can only be manually defrosted by a service engineer.
If the maximum defrosting period has passed or the defrost
temperature has been reached, the compressor switches off
and the bypass valve closes. The defrost water hose heater
continues running until the dripping time has passed. The
defrosting process is now complete.
Caution!
When using hot gas defrosting, the process should best be
conducted quickly and often. Large ice formations cannot
be melted as the defrosting process works with far lower
temperatures and therefore less radiant heat.
General notice (liability): the details of this technical documents serve for description. Consents regarding the availability of certain features or
regarding a certain purpose always require a special written agreement.
Page 48 GB
Relay
Compressor
Solenoid valve
Bypass
Defrost
water hose
heater
Lead time Defrosting
(min)
duration (min)
Defrosting temp.
(°C)
Insert sensor
between the
9th and 10th fin
Insert the sensor
to a depth of 34 mm
Right reserved to make technical changes!
Time
Dripping
time
(min)
Insert sensor between
the 1st and 2nd
evaporator tube