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12
OPERATING LIMITS
12.1
EVAPORATOR WATER FLOW RATE
The nominal water flow rate refers to a 5°C temperature difference between the evaporator inlet and outlet. The maximum
permitted flow rate features a 3°C temperature difference while the minimum one has an 8°C temperature difference at the
nominal conditions as shown in the technical sheet.
Insufficient water flow rates can cause excessively low evaporation temperatures causing the
safety devices to trigger and stopping the unit and, in some extreme cases, forming ice in the
evaporator and resulting in serious failures to the cooling circuit.
For greater details, we have attached a table below with the minimum flow rates for the plate heat exchanger to guarantee proper
operation according to the model (please note: the water flow switch is applied to protect against failed triggering of the
antifreeze probe due to the lack of flow but does not guarantee the minimum water flow rate required for correct operation of
the unit).
Model
06
08
10-
10T
12-
12T
14-14 3ph
16-16 3ph
18
3ph
Minimum water flow to be assured in chiller mode
(condition (1) technical sheet) [l/s]
0.15
0.17
0.23
0.25
0.34
0.34
0,41
Maximum water flow to be assured in chiller mode
(condition (1) technical sheet) [l/s]
0.40
0.46
0.60
0.68
0.92
0.92
1,10
Minimum flow switch water flow rate* [l/s]
0.117
0.117
0.153
0.153
0.153
0.262
0,262
Maximum flow switch water flow rate* [l/s]
0.132
0.132
0.175
0.175
0.175
0.293
0,293
* When the flow rate drops below the indicated limit (flow switch minimum water flow rate) the flow switch issues an alarm,
which may be reset only upon reaching the maximum indicated flow rate.
12.2
COLD WATER PRODUCTION (SUMMER MODE)
A minimum temperature of 5°C is allowed at the evaporator outlet: for lower temperatures, contact the Technical Department. In
this case contact our technical department to study the feasibility and assess the changes to be made according to demands. A
maximum temperature of 25°C can be maintained at the evaporator outlet in steady-state operation.
12.3
HOT WATER PRODUCTION (WINTER MODE)
When the system has reached steady state, the water inlet temperature must not drop below 25°C: lower values, not due to
transient phases or reaching steady-state, can cause system failures and could possibly break the compressor. The maximum
outlet water temperature must not exceed 60°C.
There could be failures to the regular operation of the unit or, in more critical cases, the safety devices could be triggered due to
temperatures higher than those indicated, especially if coupled with reduced water flow rates.
12.4
AMBIENT AIR TEMPERATURE AND SUMMARISED TABLE
The units are designed and built to operate in summer mode, with condensation control, at outdoor air temperatures between -
10°C and +46°C. In heat pump mode, the allowed temperature range of the outdoor air is from-20°C to +40°C depending on the
outlet water temperature as shown in the table below.
Operating limits
Water chiller mode
Room temperature
Minimum -10°C M46°C
Outlet water temperature
M5°C M25°C
Heat pump mode
Room temperature
Minimum -20°C M30°C
Outlet water temperature
M25°C M60°C
Heat pump mode for domestic hot water
Room temperature with water at maximum 39°C
Minimum -20°C M40°C
Room temperature with water at maximum 55°C
Minimum -10°C M35°C
Outlet water temperature
M25°C M60°C
The following are the graphical operating limits for air-conditioning and domestic hot water production.
