Duplex Compressors

A duplex compressor has two compressor pumps mounted on a single shared receiver tank, each with its own motor and electrical controls. A lead-lag control sequence controls the pumps so one acts as primary and the other as backup, switching roles on a schedule. If one pump fails, the other continues operating — the shop stays running.

Two reasons: redundancy and operational flexibility. Redundancy keeps the shop operating during a pump failure or scheduled maintenance. Operational flexibility means one pump handles light loads while both run during peak demand, reducing wear on a single unit and matching output to actual usage.

Duplex configurations in this collection run from roughly 10 HP combined (two 5 HP pumps) up to 30 HP combined (two 15 HP pumps), with tank sizes from 80 to 240 gallons. Total CFM output at operating pressure scales with the combined pump rating when both pumps run simultaneously.

The control panel rotates the lead pump on a schedule — typically weekly — so both pumps accumulate roughly equal run hours. During high-demand periods, the lag pump starts when tank pressure drops below a second cut-in setpoint. If the lead pump faults, the lag immediately takes over and runs as the new lead.

Three-phase 208/230/460V is standard. Each pump motor requires its own circuit at the rated amperage. A 20 HP duplex (two 10 HP pumps at 460V three-phase) typically requires two 30-amp circuits plus control circuit power. Verify with the specific model's installation manual and consult a licensed electrician.

Generally no. Duplex compressors are engineered as integrated systems with sized receivers, manifolds, and control panels matched to dual-pump operation. Field conversion is not supported by Champion Air or FS Curtis. To gain duplex capability, purchase a factory duplex unit.

Duplex units are larger than single-pump compressors but smaller than two separate compressors with comparable combined output. Typical 240-gallon horizontal duplex installations occupy roughly 7 to 8 feet of wall length and require 3 feet of clearance on the service side. Verify clearance requirements before specifying.

Each pump follows its own service schedule based on its accumulated run hours — typically displayed on the control panel hour meters. Stagger maintenance so one pump remains operational while the other is serviced. This is one of the key operational advantages of duplex over single-unit installations.