AKO AKO-16520, Руководство пользователя

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1652H302 Ed.03
14
Defrost
Types of defrost
There are 5 possible defrost types, depending on the option selected in the wizard (Inl):
Electric ( InI= 1, 2 and 3) ( d7 =0)
Defrost is performed through electrical resistors, supplying the evaporator with heat. The operation of fans in this
mode depends on parameter
F3 ; the compressor and solenoid are stopped.
By air ( InI= 4, 5 and 6) ( d7 =1)
Usually used in positive cold rooms (> 3°C), since the inside temperature of the cold room is sufficient to melt
evaporator ice. By default, the fans are activated so that air may circulate through the evaporator; to stop them,
change parameter F3 to 0. The compressor and solenoid are stopped.
Static ( InI= 11, 12 and 13)
In this type of installation, there are no evaporator fans and defrost is performed by stopping cold production.
Hot gas ( InI= 7 and 8) ( d7 =2)
The hot gas from compressor discharge is used to melt evaporator ice and, to this end, two valves are necessary:
one at the condenser input (A) (SSV relay) and another between the compressor output and the evaporator input
(B) (DEF relay).
During the process, the liquid solenoid valve (C) and the condenser input valve are closed and the evaporator input
valve is opened, forcing hot gas to pass through the latter and melting the ice.
Optionally, a high pressure switch (D) can be added to control the solenoid valve (digital input D2,
l20 =9) during
the defrost process using hot gas. If the pressure decreases, the solenoid opens to allow liquid into the tank; when
the pressure rises again, the solenoid closes.
Gnd
D2 / S3
D1
DIG. IN
SSV N DEF N FAN N COOL N A
UX 1
N H.
CRANK.
N
COND.
EVAP.
A
D
B
C