Samsung AM072FXVAFH series Service Manual page 172

Troubleshooting
: Comp. Down due to Low Pressure Protection Control
Outdoor unit display
Indoorunit display
Judgment Method ∙ Inspection when the value of low pressure sensor is 2.6kg/cm², or less for air conditioning and 1.4kg/cm² for heating.
∙ Refrigerant shortage
∙ Electronic expansion valve blocked
∙ Low pressure sensor defective
∙ Low pressure sensor defective
Cause of problem
∙ Leakage of compressor discharge check valve of not-go-end outdoor unit
∙ Error may be found when used in temperature range outside the conditions of use
(Operating outside temperature at -20°C or less for heating and operating outside temperature at -5°C or less for Cooling)
∙ When heating operation, if the water temperature and quantity are below the normal range.
1. How to check
Are all service valves open?
estimated value and the
Manifold Gauge value in range?
When heating operation
temperature and the quantity is within
Are the Indoor Unit and Outdoor
Unit EEV normally operating?
Are there any blockage inside
the Liquid Pipe Valve or the discharge check
valve of the not-go-end Outdoor Unit when only
Check the refrigerant amount.
4-76
(Water Cooled)
Duct, Cassette (1/2 Way),Console, Celing
Operation Defrost Timer Fan
× × ◑ ◑
※ ● : ON ◑ : Flash ×: OFF
Auto Trial Operation
Yes
Is the S-net
Yes
the normal range?
Yes
Yes
the pipe? (filter etc.)
No
Is there any leakage in
some Outdoor Units
are operating?
No
Cassette (4/Mini4 Way)
Filter/MPI Operation Defrost Timer
◑ × ◑ ◑
No
No
No
Yes
Yes
Yes
(cont.)
Wall-mounted (NeoForte)
Filter Operation Timer Turbo
◑ ● ◑ ◑
Connect S-net and Manifold Gauge.
(essential requirement)
Open the Service Valve
Replace Low Pressure sensor
Check the water pipes
Check the relevant EEV
Pipe inspection
Replace relevant component
Samsung Electronics