Mitsubishi Electric PKA-RP1.6GAL Service Technical Manual page 53

Control modes
4-1. Normal control
4. LEV(A)
4-2. Low discharge super heat temperature protection control
4-3. Evaporation protection control
4-4. Others
LEV opening pulse will be controlled every minute to adjust the discharge
temperature in order to let the intake super heat temperature be 0: to 5:.
• Control timing: Once per minute after 3 or 7 minutes have passed since
the compressor started.
• Opening pulse range: The following range is specified according to the
compressor operating frequency.
Opening pulse range (Lower limit to upper limit)
Compressor
frequency
PUHZ-RP1.6, 2VHA
49Hz or less 55 ~ 250
50Hz to 75Hz 85 ~ 350
76Hz to 90Hz 100 ~ 400
91Hz to more 125 ~ 480
• Opening pulse range corresponding to the change of compressor
operating frequency
Opening pulse range = Present opening pulse o (Target frequency /
Operating frequency -1) o 0.8
• Compressor start-up
Opening pulse will be adjusted according to only the change of frequency
during 3 or 7 minute start-up.
The start-up control time will be changed according to the discharge
temperature (TH4).
Discharge temperature (TH4) ] 30:: 3 minute start-up
Discharge temperature (TH4) < 30:: 7 minute start-up
Set a small value for the targeted opening pulse according to the discharge
super heat temperature.
• Correction range of the discharge super heat temperature : 10: or less
• This control does not work for 3 or 7 minutes after the compressor gets started.
20 pulse will be added to the present opening pulse in the condition written below.
Outdoor condenser/evaporator temperature (TH6) - Outdoor liquid pipe
temperature (TH3) ] 6:
W This control does not work for 3 or 7 minutes after the compressor gets started.
1 LEV opening pulse is set to 400 while the compressor is being stopped.
2 After LEV opening pulse is initialized to 400 by making 700 pulse down from
the present pulse, set the pulse to 400.
Control details
PUHZ-RP2.5, 3VHA PUHZ-RP4,5,6VHA
80 ~ 250
95 ~ 350
130 ~ 400
130 ~ 480
53
70 ~ 300
90 ~ 350
100 ~ 400
120 ~ 480
Discharge super heat
temp. is calculated from
discharge temp. (TH4)
and outdoor cond./eva.
temp. (TH6).
Remarks