35
NOTE 1:
If the thermostat wiring is incorrect, the control will
be blocked (red LED on) and all the outlets will be deactivated
when unit power is supplied.
NOTE 2:
The thermostat cable should be independent and
separate from any 230 V or 400 V cable.
Refrigerant line connections (38FZ/BZ and 40TZ/BZ)
To guarantee correct unit performance ensure that the line
length and number of bends are kept to a minimum. Avoid pipe
kinking by using large radius bends.
IMPORTANT: Always use refrigerant-grade deoxidized and
dehydrated copper tubing between the indoor and outdoor
units.
Before connecting the refrigerant lines carefully follow the
steps below:
-
Remove the nitrogen holding charge from the refrigerant
circuits.
-
Select the diameter of the copper tubing according the the
units installed and according to the distance between the
indoor and outdoor units.
-
Use silver alloy rod for soldering purposes, and ensure
that this work is done in a nitrogen atmosphere.
-
To avoid oxidation insulate the refrigerant lines
adequately.
-
Pull a vacuum in the refrigerant circuit until a pressure of
0.7 mm water column is maintained for at least 2 hours.
-
Charge the refrigerant circuit with the necessary amount
of R-407C refrigerant (in accordance with tables 1 and 2
and the length of the refrigerant lines).
-
Check there are no refrigerant leaks.
Refrigerant line selection
General
When designing refrigerant lines the following must be kept in
mind:
-
Depending on the unit arrangement:
Fig. 35 - Refrigerant lines option A
Suction line:
-
A siphon at the base of the vertical pipe run and inter-
mediate siphons every 8 m or oil separators are needed.
-
Most unfavourable condition: the suction speed in the
vertical pipe run must be more than 6 m/s.
Fig. 36 - Refrigerant lines option B
Suction line:
-
The intermediate siphon can be omitted.
-
Most unfavourable condition: the suction speed in the
vertical pipe run must be more than 6 m/s.
For both option A (Figure 34) and option B (Figure 35) the
following conditions should be observed:
-
The maximum speed permitted in any line is 15 m/s.
-
Suction line must be insulated and have a 2% slope towards
the compressor and the horizontal pipe run.
-
In long pipe runs it may be necessary to adjust the oil charge.
-
If the liquid line flow is downward, it is necessary to
install pressure equalizer for heights above 10 m.
-
The liquid should be subcooled by at least 1 K at the
restrictor inlet. In this case, if the liquid line flow is
upward and the pipe is longer than 15 m, it must be
subcooled by 1 K for each 3.5 m in excess of 15 m.
-
For each metre of refrigerant pipe installed, refrigerant has
to be added in accordance with table 5.
Table 5 - Refrigerant charge (g/m)
Diameter
3/8"
1/2"
5/8"
3/4"
7/8"
1-1/8"
1-3/8"
Liquid line
40
75
120
180
250
420
645
Suction line
6
14
23
34
47
81
123
Liquid line
Outdoor unit
Indoor unit
Cooling
(suction line)
Liquid line
Outdoor unit
Indoor unit
Cooling
(suction line)
Heat pump
Cooling
Heat pump
(discharge)
Heat pump
Cooling
Heat pump
(discharge)
Gas