Pressure Differential; Modifications - Carrier 38AJ 008 Installation, Operation And Maintenance Instructions

Pressure differential (difference between cylinder
load point and unloader points)
Turn the adjusting screw
position. In this position the differential is 41 kPa. The pressure
differential is set by turning the adjusting screw clockwise. Each
full turn increases the differential by 10 kPa. Approximately 10
turns clockwise will increase the pressure to 152 kPa.

Modifications

It is possible to convert pressure-controlled capacity reductions to electrically controlled reductions or to add capacity reductions
in accordance with the table below.
38AJ/AZ
008
010
012
014
018
024
030
036
046
062
074
Low and high pressure switch control and condensing pressure pressostat control
Pressostat control:
38AJ/AZ
008-012
014-036
046-074
12
counter-clockwise to its back stop
Fig. 7 - Pressure-operated control valve
Pressure-controlled
unloader standard
-
-
-
yes
yes
yes
yes
yes
yes
yes
yes
High pressure, kPa
Opens Closes
2500 2150
2900 2200
2900 2500
The capacity control factory settings for 4-cylinder units are:
475 kPa gauge control setpoint (cylinder load point), 70 kPa
differential, 405 kPa gauge cylinder unload point.
The settings for 6-cylinder units are: the left cylinder bank
setpoint is 482 kPa gauge (70 kPa differential); the right
cylinder bank setpoint is 469 kPa gauge (70 kPa differential).
Legend:
1 Control setpoint adjustment screw
2 Valve body
3 Sealing cap (covering the differential adjustment screw)
4 Differential pressure adjustment screw
Possibility of changing
press. to electric unloader
-
-
-
yes
yes
yes
yes
yes
yes
yes
yes
Low pressure, kPa
Opens Closes
50 150
50 150
240 390
Possibility of 2
pressure-contr. unloaders
-
-
-
yes
yes
yes
yes
yes
yes
yes
yes
Condensing pressure, kPa
Opens Closes
870 1820
870 1820