Q-Control (Reciprocating)
Simple, purpose-built controller for reciprocating packages. Do not confuse with Power$ync II/III — Q-Control is recip-only and cannot sequence rotary screws.
Manufacturer
Quincy Compressor
Display
4-line backlit LCD, 4-key membrane.
Years produced
~2016 – present on QP / QR-25 reciprocating packages.
Power supply
24 VDC control power, 120/230 VAC input.
Ambient range
0 – 46 °C.
Protection rating
IP54 front.
Relay outputs
Main contactor, unloader solenoid, aftercooler fan, alarm, remote-run.
Used on
- Quincy QP / QP MAX two-stage reciprocating 5–30 hp
- Quincy QR-25 pressure-lubricated recips
- Some Quincy QT packages when specified
Features
- Auto/Continuous/Manual selection
- Run-time and load-cycle counters
- Service reminders (oil, valves, belts)
- Auto-drain solenoid timer
Interfaces
- Modbus RTU (RS-485, option)
- Digital I/O terminal strip
- USB service port
Sensor inputs
- Discharge pressure (4–20 mA)
- Head temp (thermistor, per-stage on 2-stage)
- Oil pressure (option, splash lube omits)
- Motor PTC
Common fault codes
First checks
- Cooler & flywheel fan airflow
- Belt tension & slip
- Verify unloader relieves at unload
- Check valve condition (broken reed = huge heat)
First checks
- Oil level & viscosity
- Oil filter
- Verify pressure sensor at known-good pump
First checks
- Reset overload
- Verify FLA & voltage balance
- Check for compressor drag (seized valve, bearing)
First checks
- Verify 3 phases
- Swap 2 phases for rotation
- Check phase-monitor relay
First checks
- Unload setpoint & pressure switch
- Unloader solenoid function
- Verify pressure sensor
First checks
- Perform correct kit (oil, valves, belts)
- Reset only the completed timer
Fault list is non-exhaustive and firmware-dependent. Always confirm against the controller’s on-screen help or OEM manual.
Wiring notes
- 24 VDC control from onboard PSU
- Unloader solenoid pulses at every unload — verify diode across coil to protect controller output
- Head thermistors ride on the head with a spring clip — REPLACE the clip if it's lost tension after service
Known issues & field notes
- Head-temp thermistor clip on QP heads relaxes with heat cycling — most spurious HT-1 alarms trace to the clip, not the sensor
- USB port covered with rubber plug — leaving it open lets oil mist in and fault the port
Single service PIN, default 1234 on new commissioning; change on install. No separate factory level.
Manuals & literature
Quincy Compressor — manuals index
Public literature library
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