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Operation and Maintenance
Envistar Top 04-21
DSET.220501.07.en
Continuous product development may give rise to specification changes without notice.
Cooling circuit function
The reversible heat pump has four basic components: evaporator, condenser,
expansion valve and compressor.
A 4-way valve is used to shift between cooling and heating.
For cooling, the 4-way valve is in cooling mode. For heating, the 4-way valve
is in heating mode. This means that the coil, which was a condenser in cooling
mode, becomes an evaporator in heating mode. Conversely, the evaporator
becomes a condenser.
00035
8
3
9
11
13
14
10
16
18
19
17
4
1
5
6
2
12
15
7
Flowchart for cooling mode, reversible heat pump
1 Compressor
2
Suction gas sensor (temp after evaporator)
3
Pressure sensor, low pressure
4
Expansion valve
5
Frequency inverter
6
4-way valve
7
High pressure switch
8
Pressure sensor, high pressure
9
Temperature sensor, hot gas
10 Temperature sensor liquid line cooling
11 Temperature sensor liquid line heating
12 Temperature sensor sump
13 Extract air coil (condenser/evaporator)
14 Supply air coil (condenser/evaporator)
15 Suction gas separator
16 Exhaust air
17 Extract air
18 Outdoor air
19 Supply air
