Maximum Discharge Gas Temperature; Operating Conditions - Danfoss MLZ Selection & Application Manuallines

A
PPLICATION GUIDELINES
Maximum discharge gas
temperature
Discharge gas temperature
protection (DGT)
O
PERATING CONDITIONS
The discharge temperature depends mainly on
the combination of evaporating temperature,
condensing temperature and suction gas super-
heat. Discharge gas temperature should be con-
trolled with an isolated thermocouple or thermo-
DGT protection is required if the high and low
pressure switch settings do not protect the com-
pressor against operations beyond its specific ap-
plication envelope. Please refer to the examples
below, which illustrate where DGT protection is
required (n°1) and where it is not (n°2).
160
150
140
130
120
110
100
90
80
70
60
50
-30 -20
Example 1 (R22, SH = 20°F)
LP switch setting: LP1 = 29 PSI (5°F)
HP switch setting: HP1 = 345 PSI (142°F)
The LP and HP switches don't protect suf-
ficiently from operation outside the envelope. A
DGT protection is required to avoid operation in
the hatched area.
Discharge line
FRCC.PC.016.A1.22
stat attached to the discharge line 6 inches from
the compressor shell. Maximum discharge gas
temperature must not exceed 275°F when the
compressor is running within the approved oper-
ating envelope.
The compressor must not be allowed to cycle on
the discharge gas thermostat. Continuous opera-
tions beyond the compressor's operating range
will cause serious damage to the compressor!
A DGT accessory is available from Danfoss: refer to
page 39.
MLZ / MLM
LP1 LP2
-10 0 10 20
Evaporating temperature (°F)
Example 2 (R22, SH = 20°F)
LP switch setting: LP2 = 36 PSI (14°F)
HP switch setting: HP2 = 247 PSI (120°F)
The LP and HP switches protect from opera-
tion outside the envelope. No DGT protection
required.
Thermostat
Bracket
R22 - SH 20°F
HP1
Example 1
HP2
Example 2
30 40 50 60
Insulation
23