41
9.5 - Operating limits for stable operation (no mode
changeover)
9.5.1 - Cooling only mode
Please refer to the earlier chapters in this manual:
6.1 - Unit operating range
6.7 - Evaporator water flow rate
9.5.2 - Heat reclaim mode
Condenser water temperature
°C
Minimum
Maximum
Water entering temperature at start-up
12.5*
55
Water entering temperature during operation
20
55
Water leaving temperature during operation
25
60
Evaporator water temperature
°C
Minimum
Maximum
Water entering temperature at start-up
-
45
Water entering temperature during operation
6.8
21
Water leaving temperature during operation
3.3
15
* The water entering temperature at start-up must not be lower than 12.5 °C. For
installations with a lower temperature a three-way valve must be used.
NOTE: If the temperature at the evaporator is below 4 °C, a glycol/water solution or
the frost protection option must be used.
In part-load operation, the limitation of the condenser
leaving water temperature is due to the operating range of
the screw compressor. If the condenser leaving water
temperature is above the limit value given in the curves
below, the unit will automatically change over to the mode
without heat recovery:
9.3 - Condenser location
All heat reclaim condensers are located between the
air-cooled condensers on the upper part of the chassis,
support-ed by two cross rails. The water inlet and outlet are
on the same side.
9.4 - Condenser water connections
9.4.1 - Unit with one heat reclaim condenser (30XA 252-502)
The water flow switch must be installed at the water inlet of
the installation that arrives at the heat reclaim condenser.
Legend
1 Heat reclaim condenser
2 Entering water temperature sensor (supplied)
3 Leaving water temperature sensor (supplied)
4 Condenser water flow switch (supplied)
5 Three-way valve (not supplied)
9.4.2 - Unit with two heat reclaim condensers (30XA 602-1002)
The two condensers must be installed in parallel in the water
system of the installation. The water flow switch and the
entering/leaving water temperature sensors must be
instal-led in the line that is common to both heat reclaim
circuits and as close as possible to the condensers. A
T-piece must be provided by the installer at the water inlet
and outlet of the condensers.
For units with two condensers the maximum cable length
of the temperature sensors and the flow switch (7.5 m) is
designed to allow connection to the common inlet or outlet
in a radius of 4.5 m after routing along the width of the unit.
Legend
Please refer to the legend in chapter 9.4.1 opposite, noting that items 2, 3 and 4 -
flow switch and sensors - are placed on the common sections.
9.4.3 - Three-way valves
It is strongly recommended to install a three-way valve in
the system (not supplied with the unit). A 0-10 V output is
available on the unit electronic board to control this valve.
The valve allows bypassing of the heat reclaim condenser
entering/leaving circuit to ensure unit operation with heat
reclaim at low entering water temperature (< 12.5 °C). It also
ensures an optimal and controlled leaving water temperature.
20
25
30
35
40
45
50
55
60
65
0
5
10
15
Condenser
lea
ving
w
ater
temper
atur
e,
°C
Evaporator leaving water temperature, °C
Part load operating limits (evaporator leaving water
temperature = 7 °C)
40
45
50
55
60
30
40
50
60
70
80
90
100
Maximum condenser lea
ving w
ater
temper
atur
e,
°C
Unit load, %
Full load
Part load limit, approx. 60%
Minimum load limit, approx. 30%
Summary of Contents for Aquaforce 30XA Series
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