SENSOR FAULT P1/P2 — Supervisor Deluxe (WS series) Fault Code

Supervisor Deluxe (WS series)

These are workhorse panels with huge installed base. Keep a spare transducer and keypad tail on the truck — those two parts solve most field complaints.

Manufacturer

Sullair

Display

2-line 16-character vacuum fluorescent display with membrane keypad.

Years produced

~1995 – 2012 across the WS and LS screw packages.

Power supply

115 VAC control via internal transformer with 24 VAC logic rails.

Ambient range

0 – 46 °C.

Protection rating

NEMA 4 front when gasketed in the enclosure door.

Relay outputs

Starter coils, solenoid valves (load / blowdown), remote alarm horn, auto-restart relay.

Used on

Sullair LS-16 / LS-20 / LS-25 series
Sullair WS-1800 through WS-7500
Many shop-air 10–50 hp Sullairs of the era

Features

Full sequencing of up to 16 Sullair machines (protocol dependent)
Auto-restart after power failure with staggered delay
Hour meters for running, loaded, and each maintenance item
Adjustable pressure band with drift compensation

Interfaces

RS-485 Sullair sequencing protocol
Dry contacts for remote start/stop and alarm

Sensor inputs

P1 package discharge pressure (0–225 psi transducer)
P2 sump pressure
T1 separator / discharge temperature (RTD probe)
Differential filter inputs (option)

Fault code lookup

HI TEMP Separator/discharge RTD over trip point (typ. 235 °F / 113 °C).

First checks

Fluid level and cooler
Thermal valve kit condition
Probe resistance (~110 Ω class per 100 °F rise from 32 °F reference)

See trigger conditions & affected models →

SUMP PRESSURE LOW Sump failed to build minimum pressure at load.

First checks

Minimum pressure/check valve
Inlet valve not opening fully
Fluid aeration from low level

See trigger conditions & affected models →

SENSOR FAULT P1/P2 Pressure transducer out of range.

First checks

5 VDC excitation present
Sensor connector corrosion
Known-good sensor swap

See trigger conditions & affected models →

SEQ COMM LOSS Sequencing network dropped a machine.

First checks

Daisy-chain polarity A-to-A, B-to-B
Termination jumpers at end units
Each machine address unique

See trigger conditions & affected models →

STARTER FAULT Starter auxiliary feedback missing after run command.

First checks

Contactor coil voltage
Aux contact block condition
Overload reset state

See trigger conditions & affected models →

Fault list is non-exhaustive and firmware-dependent. Always confirm against the controller’s on-screen help or OEM manual.

Sensor pin resistance & signal values

Pin-level resistance and signal values for the sensor types this controller uses. Works offline. De-energise the panel and lift one lead before ohming any element.

Wiring notes

24 VAC logic — meter both sides to the transformer common, not to chassis, when tracing inputs
Sequencing runs on twisted shielded pair, shield grounded at the master only
Remote start/stop is a maintained dry contact, NOT a momentary

Known issues & field notes

VFD display dims with age — the filament supply caps on the display board dry out; board repair or display replacement required
Keypad membrane tails crack at the fold — intermittent keys mean replacement tail, not a bad controller

Calibration menu access code set at commissioning; documented in the unit's wiring packet.

Manuals & literature

Sullair — support portal

Manuals are per-product — search model below

Browse all OEM manual portals →

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