Electronic Expansion Valve; Valve Pre-Opening; Equalizations At Start-Up; Pressure Equalizations At Compressor Shutdown - Mitsubishi Electric i-BX-N Technical Manual

TM_i-BX(-N)_NC05_00_06_20_EN
4.8

ELECTRONIC EXPANSION VALVE

The electronic expansion valve is driven based on the PID algorithm, the proportional, integral and derivative values of which are set using the
parameter.
4.8.1

VALVE PRE-OPENING

Using parameter 136T it is possible to set the type of valve pre-opening before the start of the compressor.
With 136T = YES, valve pre-opening is equal to the number of steps defined by parameter 1360 (no relation with the requested capacity).
136K defines the pre-opening time.
Other parameters: 1386 pre-opening in chiller
136U pre-opening in heat pump
With 136T = NO valve pre-opening is based on the requested capacity.
On i-BX-N units always set 136T = YES
4.8.2

EQUALIZATIONS AT START-UP

Parameter 131K is used to set the type of valve pre-opening before the start of the compressor in compressor startup conditions with pressure
difference defined by parameter 1358 not being met.
With 131K = YES, the valve pre-opening is equal to the number of steps defined by parameter 131Q (no relation with the requested capacity).
On i-BX-N units always set 131K = YES
Other parameters: 1359 maximum equalization time
4.8.3

PRESSURE EQUALIZATIONS AT COMPRESSOR SHUTDOWN

In order to guarantee pressure equalization, at compressor shutdown the valve will open to the set number of steps (equal to parameter 1362 "Steps
valve open eq."), and will maintain this opening level for the time set in parameter 1361 ("time equalization EEV"). At the lapsing of this time, the valve
will switch to the set stand-by position.
Also this function is managed by parameter 131K = YES.
On i-BX-N units always set 131K = YES
For the default values of the various parameters, see the parameters table
MEHITS S.p.A. ● TECHNICAL MANUAL
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Version NC05 - Translation of the Original Instructions