Advanced Scroll Temperature Protection (Astp) - Lennox FLEXY II Series Installation, Operating And Maintenance

A S
DVANCED CROLL
O M E
PERATION ODE XPLANA TION
 Protection is activ ated when Scroll Discharge
Port. Reaches 150°C (+/- 17K)
 Compressor is protected as « Unloaded » but
continues to run

Protection mode balances
discharge/suction pressure
-
-
Motor protector opens (Klyxon)


Compressor turns off, cools
 Motor protector resets, compressor restarts

Bi-metal disk resets bef ore motor
protection

Cycle will continue until cause of
ov erheat is fixed
180
150
120
ASTP
Klyxon
90
65
Compressor Runs
40
Balanced
Pressures
0 20
DISC OPENS,
SCROLLS UNLOAD
IOM – FLEXY II – 1007 – E
T P
EMPERATURE ROTECTION
Motor heat builds inside
compressor
No ref rigerant flow to carry
motor heat away
Temperature Behavior with ASTP Protection
Discharge
Port
40 60
Time (Minutes)
MOTOR PROTECTOR
OPENS, PUMP TURNS
OFF
(ASTP)
S C
ERVICE A OMPRESSOR
 What to do?

 DO NOT ASSUME A COMPRESSOR RUNNING
UNLOADED (BALANCE PRESSURE) IS A
FAILURE
 Likely situations where protection may activate :

Initial system charging (or recharging after
serv icing)

Field servicing (system problem causes
ov erheating)
Compressor
off
80 100 120
If a protected compressor is identif ied
-
Stop the compressor
-
Allow to cool thoroughly
-
Restart pump & check f or
normal operation
-
Compressor is run with too little
sy stem charge
 Very common on split
sy stem
 Will result in v ery low
suction pressures (<1.7
Bars)
 Do not disable low
pressure cutouts while
charging
Charge high-side with

liquid f irst
-
Technician will observe
« Balanced pressures »
-
Risk of misdiagnosis as failed
compressor
-
Must stop pump, cool
thoroughly , reset
140 160
PROTECTOR RESETS,
PUMP RESTARTS FULLY
LOADED
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