Lennox ROOFTOP FLEXY FXK 55, Installation, Operating And Maintenance Manual

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ADVANCED SCROLL TEMPERATURE PROTECTION (ASTP)
FLEXYII_WSHP-IOM-1307-E - 56 -
O
PERATION
M
ODE
E
XPLANATION
v
Protection is activated when Scroll Discharge Port.
Reaches 150°C (+/- 17K)
v
Compressor is protected as « Unloaded » but
continues to run
•
Protection mode balances discharge/suction
pressure
-
Motor heat builds inside compressor
-
No refrigerant flow to carry motor heat away
v
Motor protector opens (Klyxon)
•
Compressor turns off, cools
v
Motor protector resets, compressor restarts
•
Bi-metal disk resets before motor protection
•
Cycle will continue until cause of overheat is fixed
S
ERVICE A
C
OMPRESSOR
v
What to do?
•
If a protected compressor is identified
-
Stop the compressor
-
Allow to cool thoroughly
-
Restart pump & check for normal operation
v
DO NOT ASSUME A COMPRESSOR RUNNING
UNLOADED (BALANCE PRESSURE) IS A FAILURE
v
Likely situations where protection may activate :
•
Initial system charging (or recharging after servicing)
-
Compressor is run with too little system charge
§
Very common on split system
§
Will result in very low suction pressures (<1.7
Bars)
§
Do not disable low pressure cutouts while
charging
§
Charge high-side with liquid first
•
Field servicing (system problem causes overheating)
-
Technician will observe « Balanced pressures »
-
Risk of misdiagnosis as failed compressor
-
Must stop pump, cool thoroughly, reset
Temperature Behavior with ASTP Protection
40
65
90
120
150
180
0 20 40 60 80 100 120 140 160
Time (Minutes)
T
em
p
er
at
u
re (
°C
)
DISC OPENS,
SCROLLS UNLOAD
Compressor Runs
Balanced
Pressures
PROTECTOR RESETS,
PUMP RESTARTS FULLY
LOADED
MOTOR PROTECTOR
OPENS, PUMP TURNS
OFF
Discharge
Port
Klyxon
ASTP
Compressor
off