Maximum Discharge Gas Temperature - Danfoss MLM Series Application Manuallines

A G
PPLICATION UIDELINES
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 ther-
DGT protection is required if the high and low
pressure switch settings do not protect the com-
pressor against operations beyond its specifi c 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).
75
MLZ / MLM
70
65
60
55
50
45
40
35
30
25
20
15
10
-35 -30 -25
Example 1 (R22, SH = 11 K)
LP switch setting: LP1 = 2 bar (g) (-15°C)
HP switch setting: HP1 = 23.8 bar (g) (61°C)
 The LP and HP switches don't protect suffi ciently from opera-
tion outside the envelope. A DGT protection is required to avoid
operation in the hatched area.
Discharge line
FRCC.PC.015.A4.02
mostat attached to the discharge line 15 cm (6
inches) from the compressor shell. Maximum dis-
charge gas temperature must not exceed 135°C
(275°F) when the compressor is running within
the approved operating 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 section "Spare parts & accessories".
Example 1

Example 2
LP1 LP2
-20 -15 -10 -5
Evaporating temperature (°C)
Example 2 (R22, SH = 11 K)
LP switch setting: LP2 = 2.5 bar (g) (-10°C)
HP switch setting: HP2 = 18 bar (g) (49°C)
 The LP and HP switches protect from operation outside the
envelope. No DGT protection required.
Thermostat
Bracket
R22 - SH 11K
HP1
HP2
0 5 10 15
Insulation
20
25