Intellisys SG / SE (legacy)
When quoting a repair on an SG, price the Xe retrofit alongside it — board availability is the deciding factor more often than labor.
Manufacturer
Ingersoll Rand
Display
2-line vacuum-fluorescent or LCD text display with tactile keypad.
Years produced
~1995 – 2015. Widely still in service; parts increasingly scarce.
Power supply
24 VDC from control transformer; some builds 115 VAC control circuit.
Ambient range
0 – 46 °C.
Protection rating
IP54 front panel.
Relay outputs
Star/delta contactors, load solenoid, blowdown, common alarm.
Replaced by
Xe-70M / Xe-90M
Used on
- IR SSR / R-Series pre-2015
- UP6 Series
- Some Nirvana fixed-speed frames
Features
- Online/offline and modulation control
- Basic maintenance hour timers
- Simple alarm history (last few events)
Interfaces
- Volt-free run/alarm contacts
- Optional Intellisys communication module (RS-485)
Sensor inputs
- Sump pressure
- Package discharge pressure
- Airend discharge temp (thermistor/RTD)
- Inlet vacuum switch
Fault code lookup
First checks
- Coolant level and cooler cleanliness
- Thermostatic valve
- Sensor resistance check
First checks
- Blowdown valve leaking
- Inlet valve stuck closed
- Transducer zero
First checks
- Minimum pressure valve stuck
- Separator plugged
- Unload solenoid not shifting
First checks
- Amp draw vs nameplate
- Voltage imbalance
- Starter contacts pitted
First checks
- Swap two legs
- Verify all three phases present
First checks
- Service the item then reset that timer only
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
- Control transformer taps must match site voltage — mis-tapped 208 V panels cause random resets that look like controller failure
- Sensor grounds land on a single panel star point; daisy-chained grounds cause erratic temperature readings
Known issues & field notes
- Vacuum-fluorescent displays dim to unreadable after ~15 years; the CPU still works
- Original controller boards are largely obsolete — most shops now retrofit to Xe-70M/90M rather than repair
Service parameters are behind a dealer code entered from the keypad; no published universal code.
Manuals & literature
Ingersoll Rand — support portal
Customer Care → Manuals & Parts (login often required)
Your manuals
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