Quincy Q-Master Sequencer

Plant master for Quincy fleets. Pairs with each machine's local Power$ync II/III panel. Mixed-brand plants can be run in dry-contact mode but lose per-unit trend visibility.

Manufacturer

Quincy Compressor

Display

5.7-inch color TFT touch, membrane bezel.

Years produced

~2012 – present, multiple hardware revisions.

Power supply

24 VDC control power, 120 VAC input.

Ambient range

0 – 46 °C.

Protection rating

IP54 front (NEMA 12 wall-mount enclosure).

Relay outputs

Per-machine run/stop dry contacts, common alarm, standby, dryer enable.

Used on

Networks of Quincy QGS / QSI / QSV rotary screws
Mixed-brand plants via dry-contact enable

Features

Sequences up to 12 compressors (mixed VSD + fixed)
Equal run-hours or lead/lag priority scheduling
Cascade or narrow-band control (adaptive on VSD-primary systems)
Weekly / holiday scheduling with 16 events
Event log with USB export

Interfaces

Ethernet Modbus TCP
RS-485 Modbus RTU
Digital I/O terminal strip
USB service
Optional cellular telematics

Sensor inputs

Common header pressure (4–20 mA)
Ambient temp (option)
Dewpoint (Modbus, option)

Common fault codes

M-Loss-n Unit Comm Loss Master lost Modbus link to unit n.

First checks

Verify cable & 120 Ω termination
Check slave node address matches config
Confirm unit's controller is powered and in Auto

See trigger conditions & affected models →

H-Sens Header Sensor Fault Header pressure sensor open / out-of-range.

First checks

Verify 24 VDC loop
Test sensor at known pressure
Check for condensate in the pressure line

See trigger conditions & affected models →

H-Low System Pressure Low Header < low-limit for > delay.

First checks

All machines in Auto?
Large leak or open service valve?
Review event log for cascading trips

See trigger conditions & affected models →

H-High System Pressure High Header > high-limit.

First checks

Unload setpoints on each unit
Check for a compressor stuck in load
Inlet valve stuck open on lead unit

See trigger conditions & affected models →

E-Stop Sequencer E-Stop Sequencer E-stop loop opened.

First checks

Release E-stop
Check remote loop wiring

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.

Wiring notes

Modbus RTU to Quincy Power$ync-equipped units — daisy-chain with 120 Ω termination at each end
Legacy Quincy or other-brand units wire via dry-contact enable + run-feedback + fault-feedback pairs
Header pressure sensor MUST be on the plant discharge header, downstream of all machines and the receiver

Known issues & field notes

Ethernet port on early hardware revs sensitive to ground loops — isolate with a media converter on long runs
Firmware < 2.10 could double-count run hours after Modbus reconnect — update recommended

Technician and Service PINs — default technician PIN is often 2222 on new commissioning; MUST be changed. Service level is Quincy-locked.

Manuals & literature

Quincy Compressor — manuals index

Public literature library

Direct PDFs

Browse all OEM manual portals →

Your manuals