3
2
1
4
CC-0056
1
2
3
4
Thermostat
Discharge line
Bracket
Insulation
Discharge temperature protection
The discharge gas temperature must not exceed 135°C. The discharge gas thermostat accessory kit (code 7750009)
includes all components required for installation as shown below. The thermostat must be attached to the
discharge line within 150 mm from the compressor discharge port and must be thermally insulated and tightly fixed
on the pipe.
Figure 22: Discharge temperature protection
A DGT protection is required if the high and low pressure switch settings do not protect the compressor against
operations beyond its specific application envelope. Please refer to the examples below, which illustrate where DGT
protection is required (Ex.1) and where it is not (Ex.2). A discharge gas temperature protection device must be
installed on all heat pumps. In reversible air-to-air and air-to-water heat pumps the discharge temperature must be
monitored during development test by the equipment manufacturer. The DGT should be set to open at a discharge
gas temperature of 135°C. The compressor must not be allowed to cycle on the discharge gas thermostat.
Continuous operations beyond the compressor’s operating range will cause serious damage to the compressor!
C
o
n
d
e
n
si
n
g
t
e
m
p
e
ra
tu
re
(
°C
)
Evaporating temperature (°F)
C
o
n
d
e
n
si
n
g
t
e
m
p
e
ra
tu
re
(
°F
)
CC-0045
Evaporating temperature (°C)
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
-40
-31
-22
-13
-4
5
14
23
32
41
50
59
68
77
86
10
15
20
25
30
35
40
45
50
55
60
65
70
75
50
59
68
77
86
95
104
113
122
131
140
149
158
167
LP1
HP2
HP1
Map example R410A
Example 1
Example 2
LP2
Example 1
(R410A)
LP switch setting: LP1 = 3.3 bar (g) (-15.5°C)
HP switch setting: HP1 = 38 bar (g) (62°C)
Risk of operation beyond the application envelope.
DGT protection required.
Example 2
(R410A)
LP switch setting: LP2 = 4.6 bar (g) (-10.5°C)
HP switch setting: HP2 = 31 bar (g) (52°C)
© Danfoss | Climate Solutions | 2022.09
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