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8 - HEAT RECLAIM CONDENSER OPTION (OPTION 50)
8.7 - Flow control
The water flow switch supplied needs to be installed at the heat
reclaim condenser water inlet and protects the conden-ser loop
against low water flow conditions. When the heat reclaim mode
is required, a signal from the additional board output activates the
system pump. Once the pump is started, flow detection takes
place for one minute. If no flow is detected by the end of this time:
1. Changeover to the heat reclaim mode is not permitted
2. Mode is changed to cooling only mode when the water flow
rate is low, accompanied by a water flow detection alarm.
Legend
1
Evaporator
2
Heat reclaim condenser
3
Air condenser (coils)
4
Compressor
5
Expansion device (EXV)
6
Motorised valve - heat reclaim mode
7
Motorised valve - cooling only mode
8
Solenoid valve - charge recovery in heat reclaim mode
9
Solenoid valve - charge recovery in cooling only mode
10 Check valve
11
Pressure and temperature measurement to calculate the liquid sub-cooling to
optimise the charge recovery
12 Check valve with capillary
8.8 - Heat reclaim operation
Changeover from one mode to the other (changeover from heat
exchange at the air condenser to heat exchange at the water
condenser and vice versa) is ensured by motorised two-way valves
located upstream of the air and water condensers.
ATTENTION: Mode changes may lead to higher sound levels
than the levels at stable operation.
If the heat reclaim mode has been selected, the logic compares
the condenser water entering temperature with the setpoint.
Depending on this difference the unit is either activated or
deactivated in heat reclaim mode, maintaining a deadband that
is centred on the setpoint.
The deadband of 5 K is controlled by default. For more details on
the heat reclaim operation logic please refer to the 30XAS control
manual in chapter "Heat reclaim module option".
8.9 - Condenser pump selection
Heat reclaim condenser water flow rate/pressure drop
Heat reclaim condenser pressure drop in water flow
rate function
70
60
50
40
30
20
10
0
0
10
Water flow rate, l/s
1
Condenser 12" (water volume = 55 litres)
2
Condenser 14" (water volume = 68 litres)
For units with a water condenser please refer to chapter 8.1.
8.10 - Frost protection
The heat reclaim condenser is equippped with electric heaters to
protect the condenser against frost. These are activated if the
condenser entering and leaving water temperatures are below 3
°C and deactivated, if they are higher than 4.4 °C.
20
30
40
27
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