for this type of valve, for example, the maximum number of opening steps is 480.
Refrigerant type (par. PH)
This is used to set the type of refrigerant used in the system. The table below shows the possible types of
refrigerant and the associated values of PH. For compatibility with the E2V valve, see the manual for the
connected driver. Contact CAREL if installing E2V valves in systems that use refrigerants not listed in the
table.
Code Description Def Min Max UOM User
User
terminal
PH
Refrigerant
Val. Desc. Val. Desc. Val. Desc.
0 Custom gas 14 R417A 28 HFO1234ze
1 R22 15 R422D 29 R455A
2 R134a 16 R413A 30 R170
3 R404A 17 R422A 31 R442A
4 R407C 18 R423A 32 R447A
5 R410A 19 R407A 33 R448A
6 R507A 20 R427A 34 R449A
7 R290 21 R245Fa 35 R450A
8 R600 22 R407F 36 R452A
9 R600a 23 R32 37 R508B
10 R717 24 HTR01 38 R452B
11 R744 25 HTR02 39 R513A
12 R728 26 R23 40 R454B
13 R1270 27 HFO1234yf
3 0 40 - S NO
Important: if the type of refrigerant is incorrect, the superheat measurement will be wrong, with the
risk of liquid returning to the compressor.
In addition, a temperature/pressure conversion curve corresponding to an arbitrary new refrigerant can
be entered (custom gas) by writing from the supervisor suitable coefficients, a numeric ID for the gas and
the CRC protection value. The coefficients are provided by Carel. Once the new refrigerant has been
entered, it will be available by setting parameter PH to 0. The value 0 can only be applied if the cyclic
redundancy check (CRC) does not detect errors. If the coefficients are modified after having chosen to use
a custom refrigerant (PH = 0) and the CRC check fails, alarm GPE will be displayed on the user interface
and control will stop.
Superheat set point (par. P3)
Code Description Def Min Max UOM User
User
terminal
P3 Superheat set point 10 0 25 K S YES
The parameter that electronic valve control is based on is superheat, which effectively tells whether or
not there is liquid at the evaporator outlet. Superheat is calculated as the difference between:
superheated gas temperature (measured by a temperature sensor located at the end of the outlet tGS)
and the saturated evaporation temperature (calculated based on the reading of a pressure transducer
located at the evaporator outlet (PEu/tEu) and using the Tsat(P) conversion curve for each refrigerant)
SH = tGS - tEu
SH = superheat (K)
tGS = superheated gas temperature (°C/°F);
tEu = saturated evaporation temperature, converted from the pressure (°C/°F).
If superheat is high it means that the evaporation process is completed well before the evaporator outlet,
and therefore flow-rate of refrigerant through the valve is insufficient. This causes a reduction in cooling
efficiency due to the failure to exploit part of the evaporator.
74|5. Functions
MPXone +0300086EN rel. 1.0– 04.09.2018
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