Mitsubishi Electric CITY MULTI PUHY-400YMF-B, Service Handbook

Page: 88 / 204

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(11) Liquid Refrigerant Correction Control
The liquid refrigerant correction control adjusts the liquid refrigerant amounts between both accumulators in the
unlikely event that the liquid refrigerant amount in both the constant and variable capacity unit accumulators should
be insufficient, or if and excessive amount of liquid refrigerant is returned from either accumulator.
During this operation, Service LED No. 4 on the variable capacity unit will light up.
Direction of Accumula-
tor Liquid Transfer
Variable Capacity Unit
Constant Capacity Unit
↓
Indoor Unit
Variable Capacity Unit
↓
Constant Capacity Unit
Variable Capacity Unit
↓
Constant Capacity Unit
Variable Capacity Unit
↓
Constant Capacity Unit
Variable Capacity Unit
↓
Constant Capacity Unit
Constant Capacity Unit
↓
Variable Capacity Unit
Constant Capacity Unit
↓
Variable Capacity Unit
Start Conditions
• In heating mode
• Run and stop indoor units
are mixed.
• Pd 13k (1.27 MPa), or
during an accumulator
overflow preliminary error.
• Td < 110
°
C
• In heating mode
• While the constant capacity
unit is stopped.
• During an accumulator
overflow preliminary error
in the variable capacity unit
(AL1 = 2)
• TdSH < 40 deg *1
• In heating mode
• During constant capacity
unit operation
• When AL1 = 2 is detected in
the variable capacity unit.
• TdSH < 40 deg *1
• In cooling mode
• While the constant capacity
unit is stopped.
• During an accumulator
overflow preliminary error
in the variable capacity unit
(AL1 = 2)
• Constant capacity unit
AL2 = 0 or 1
• Variable capacity unit
TH6 < 25
°
C
• In heating mode
• Constant capacity unit
switches from operation to
stopping.
• Constant capacity unit AL2 = 0
• In heating mode
• During an accumulator
overflow error delay in the
constant capacity unit
(AL2 = 2)
• Variable capacity unit
AL1 = 0 or 1
• During cooling or heating
• During an accumulator
overflow preliminary error
in the constant capacity
unit (AL2 = 2)
• Variable capacity unit
AL1 = 0 or 1
Actuator Action
Com-
pressor
–
OFF
OFF
OFF
OFF
–
OFF
Constant Capacity Unit
Variable
capacity
unit
–
–
–
Opera-
tion
fre-
quency
level
up
–
Opera-
tion
fre-
quency
level
down
21S4a,
b
ON
Indoor
Unit
Opera-
tion:
nor-
mal
control
Stop:
LEV = 60
–
–
All
indoor
unit
LEV = 60
–
–
All
indoor
unit
LEV = 60
Stopping
Conditions
While all
indoor units
are operat-
ing
Td 115
°
C
• AL1 = 0 or 1
• Continuing
for 20
minutes
• AL1 = 0 or 1
• AL2 = 2
• Continuing
for 10
minutes
• AL1 = 0 or 1
• Continuing
for 15
minutes
• AL1 = 0 or 1
• Continuing
for 3 ~ 6
minutes
• AL2 = 0 or 1
• AL1 = 2
• Continuing
for 10
minutes
• AL1 = 2
• Continuing
for 4
minutes
LED Monitor
No.4
• Verify
surplus
refrigerant
• LD1 lights
up
Liquid
refrigerant
control
2
LD3 lights
up
Liquid
refrigerant
control
4
LD5 lights
up
Liquid
refrigerant
control
6
LD7 lights
up
Liquid
refrigerant
control
7
LD8 lights
up
Liquid
refrigerant
control
3
LD4 lights
up
Liquid
refrigerant
control
5
LD6 lights
up
LEV2
–
2000
2000
2000
2000
–
2000
SV5b
–
ON
(open)
ON
(open)
ON
(open)
ON
(open)
–
ON
(open)
Other
–
–
–
Fan
ON
–
–
LEV1 =
480
SV4 ON
21S4
OFF
* 1 TdSH (Discharge temperature superheating) = Discharge temperature (TH11 or TH12) - Tc (High pressure saturation
temperature)