D-EIMHP01505-22_00EN 26/59
OPERATION RANGE HEATING
– EWYT-CZ
EWYT021~064-CZ
Figure 18
– Operating limits on EWYTCZ in heating mode
OAT
Outside ambient temperature
CLWT
Condenser Leaving water temperature
Ref. 1
Certain unit sizes might work in part load in this area
The charts shown above constitute a guideline on operating limits in the range.
Refer to the CSS selection software for the actual operating limits in the working conditions for each
model.
4.14. Operating stability and minimum water content in the system
For the correct functioning of the machines, it is important to guarantee a minimum water content inside the system,
avoiding an excessive number of compressor startups and stops. In fact, every time the compressor starts working, an
excessive amount of oil from the compressor enters the refrigerant circuit and at the same time there is an increase in the
temperature of the compressor stator, generated by the inrush current of the starting. In order to prevent damage to the
compressor, the control system will therefore permit no more than 10 startups per hour. The plant where the unit is installed
must therefore ensure that the overall water content allows constant operation of the unit and consequently also greater
environmental comfort.
As a general indication the water content should not be less than the values in the following table:
Heat Pump
Suggested l/kW
Min water content [l]
EWYT021CZ(I/O)-A1
5.0
100
EWYT032CZ(I/O)-A1
4.9
160
EWYT040CZ(I/O)-A1
4.6
180
EWYT064CZ(I/O)-A2
2.7
170
Table 12
– Minimum water content in the system
Extra water may be required in critical processes or in spaces with a high thermal load.
The difference in startup temperature may vary from 1 to 5 K. This has an impact on the minimum water volume required
when the unit is functioning in cooling mode. The unit is pre-set for a start-up temperature difference of 2.5 K.
The Thermo ON condition is shown below:
EWT > Se S
tartup ∆T
Default
Max
Min
S
tartup ∆T (K
)
2.5
5
1
1
