HVAC
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PRESSURE SWITCHES
TRINARY PRESSURE SWITCHES - GENERATION II
This switch assembly performs three distinct functions. The first function prevents the compressor from
operating if system charge is lost or ambient temperature is too low. The second stops compressor if
head pressure increases to unsafe levels. It automatically resets when pressure drops back to normal.
The third function is a shutter⁄fan override switch that keeps head pressure within normal range by
opening shutters or operating engine fan to increase air flow across condenser when head pressure
rises above set valve. Install Trinary on liquid side of A⁄C system between condenser and expansion
valve. For use with R-12 and R-134a
OPENS
CLOSES
LOW PRESSURE PROTECTION
22.5 ± 7.5 PSIG (descending pressure)
40 PSIG maximum (rising pressure)
HIGH PRESSURE PROTECTION
325 ± 25 PSIG
230 ± 20 PSIG
SHUTTER FAN⁄OVERRIDE
35 - 60 PSIG (rising pressure)
200 - 230 PSIG
BELOW CLOSING PRESSURE
ABP N83 318149
ABP N83 322175
TRINARY™
E/C Connection end of TRINARYTM
4
3
1
2
7/16-20 UNF-2B female
3/8-24 UNF-2A male
thread for installation
thread with bulkhead
on male Schrader-type
type seal using a 2-012
Terminals 1 & 2
valve
O-Ring
Controls Clutch High/Low Pressure Protection
Shutter/fan switch is
Shutter/fan switch is
Terminal 1:
normally open
normally closed
To compressor clutch “compressor” black wire
Terminal 2:
ABP N83 322303
ABP N83 318009
To thermostat “AC/Thermostat” black/white
wire
Terminals 3 & 4
Controls Fan Clutch or Shutters
Terminal 3:
To solenoid valve “override” yellow wire
Terminal 4:
To ignition “DC power” orange wire
ELECTRICAL
7/16-20 UNF-2B female
3/8-24 UNF-2A male
7 Amp Resistive
thread for installation
thread with bulkhead
4 Amp Inductive
on male Schrader-type
type seal using a 2-012
valve
O-Ring
28 Volt D.C. Maximum
Shutter/fan switch is
Shutter/fan switch is
2.50 Series Male Tab Terminals
normally closed
normally open
RED DOT TRINARYTM HARNESS
ABP N83 318131
TRINARYTM boot (provides a molded 4 wire connection to
Trinary switch; lead wires are 28” long.) helps eliminate
terminal corrosion and breakage.