Johnson Controls DHW18CMB21S, Руководство по обслуживанию

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12
Technical Information
Service Manual
6. Function and Control
1 Basic functions of the system
1.1 Cooling Mode
1.1.1 Cooling conditions and process:
When turning on the unit for cooling operation, if any of the indoor units calls for cooling the system will start in cooling mode. In
this case, the electronic expansion valve, the outdoor fan and the compressor start operation.
1.1.2 Stop in cooling operation
1.1.2.1 Compressor stops
The compressor stops immediately
;
the outdoor fan stops after 1min.
1.1.2.2
If any
of the indoor units
needs cooling, the outdoor unit will still be operating in the cool mode
(the compressor does not
stop)
The compressor operates immediately according to the required frequency. For the indoor unit with no requirement, the
corresponding electronic expansion valve is closed.
1.1.3 Cooling mode
switches
to heating mode
When the unit
switches
to heating mode, the 4-way valve is energized after the compressor stops for 2min.
1.1.4 4-way valve:
I
n this mode, the 4-way valve is
de-energized
.
1.1.5 Outdoor fan control in cooling mode
The outdoor fan starts 5s
before
the starting of compressor. The outdoor fan will run in high speed for 3min after starting and
then it will run in
the
set speed. The fan shall run at every speed for at least 80s. (When the quantity of running indoor
unit
s
is changed, the unit will enter the control described in 1.3.5.1 and 1.3.5.2)
.
When the compressor stops, the outdoor fan runs at present speed and stops after 1min.
1.2 Dry Mode
(also called dehumidification mode)
1.2.1 The dry conditions and process are the same as those in cooling mode
.
1.2.2 The status of 4-way valve:
De-energized .
1.2.3 The temperature setting range:
60.8°F - 86°F (
16
-
30 ć
) .
1.2.4 Protection function:
T
he same as those in cooling mode
.
1.2.5 In dry mode, the maximum value A of the capacity requirement percentage of single unit is 90% of that in cooling mode.
The open condition of the electronic expansion valve, outdoor fan and compressor is the same as those in cooling mode.
1.3 Heating Mode
1.3.1 Cooling conditions and process:
When one of the indoor units reaches the heating operation condition, the unit starts heating operation.
1.3.2 Stop in heating operation:
1.3.2.1 When all the indoor units reach the stop condition, the compressor stops and the outdoor fan stops after 1min
.
1.3.2.2 Some of the indoor units reach the stop condition
The compressor reduces the frequency immediately and operates according to the required frequency
.
1.3.2.3 Heating mode transfers to cooling mode (dry mode), fan mode
a.
The compressor stops;
b.
T
he power of 4-way valve is cut off after 2min;
c.
T
he outdoor fan stops after 1min;
d.
T
he status of
4-way valve:
De-
energized
.