Emerson Copeland EazyCool OMQ-56-Nxx-TWD Series Application Manuallines page 10

1) PS2-W7A: Alco Controls® dual pressure switch with automatic reset (for single
compressor unit)
The switch is equipped with display scale and pointers to indicate the
approximate settings. The display scales are printed in relative pressure
units "bar" and "psi".
For precise setting of the control, external gauges must be used.
The PS2-W7A has the following characteristics:
Automatic reset dual pressure controls
Combined pressure limiter for low pressure / high-pressure
protection.
On pressure rise above the upper setpoint, contacts 1-2 open and
contacts 1-4 close.
On decreasing pressure below lower setpoint contacts 1-4 open and
contacts 1-2 close.
Adjustable dual pressure switch
Setpoint adjustment range: LP (left) = -0.5 to 7 bar and HP (right) = 6 to 31 bar.
Differential adjustment range: LP = 0,5 to 5 bar, HP = 4 bar.
Factory setting: LP = 3,5 / 4,5 bar, HP = 20 bar.
2) PS1-W3A: Alco Controls single low pressure switch with automatic
reset
The control is equipped with display scale and pointers to indicate the
approximate settings.
The display scales are printed in relative pressure units "bar" and "psi".
For precise setting of the control, external gauges must be used.
The PS1-W3A has the following characteristics:
Automatic reset single pressure controls
Pressure limiter for low-pressure protection.
On decreasing pressure below lower set-point contacts 1-4 open and
contacts 1-2 close.
Adjustable single pressure switch
Setpoint adjustment range: = -0.5 to 7 bar.
Differential adjustment range: = 0,5 to 5 bar.
Factory setting: = 3,5 / 4,5 bar.
3) PS3-WF4-HNS: Alco Controls high pressure switch with an automatic reset
Automatic reset single pressure switch
Pressure limiter for high-pressure protection.
Switches from 1-2 to 1-4 on rising pressure and from 1-4 to 1-2 on falling
pressure.
Fixed switch point settings
Cut-out point: 22 bar
Cut-in point: 26.2 bar.
C6.1.4/0305/E
Condensing Unit For Refrigeration Networks
9
2 4
p
1
- +
2 4
p
1
- +
Part no: 3136433