Quincy 4103D12HCB20M QT MAX 10 HP 120-Gallon Two-Stage Air Compressor, 208V 3-Phase

Most compressors in this class are sold on how much air they make. The reason to look at this one is what happens to the air after it is made. The QT MAX package puts a built-in, air-cooled aftercooler downstream of the pump, with a temperature-driven variable-speed fan that spins harder as the machine gets hotter. That single component is what separates this horizontal unit from the vertical QT Pro machines sitting beside it in our catalogue, and it is the component that decides whether your air line runs wet or dry.

Underneath the cooling hardware it is conventional heavy industrial equipment, and conventional is the compliment here: a splash-lubricated cast-iron pump with aluminium heads, belt driven from a 1,750 RPM industrial motor, mounted on a horizontal 120-gallon receiver. Quincy rates the pump for more than 50,000 hours of service. The motor on this particular part number is wound for 208V, 3-phase power.

What an aftercooler actually does for you

Air leaving a two-stage pump is hot, and hot air carries water vapour that cold air cannot hold. Without a cooler, that vapour travels into the receiver and condenses wherever the pipe finally gets cool enough — which, in a working shop, tends to be inside a die grinder, a plasma torch consumable, or the last three feet of hose before a spray gun. An aftercooler forces the condensation to happen at the tank, on purpose, in the one place where you have a drain.

That is why the automatic electronic tank drain matters as much as the cooler: water deliberately dropped out of the air still has to be removed on a schedule, and rust in a receiver starts as condensate nobody drained.

Two stages, and the cooler in between

Two-stage compression takes the air up in two bites rather than one. The first cylinder raises it to an intermediate pressure, the finned intercooler pulls the heat back out of it, and the second cylinder takes the cooled, denser charge the rest of the way to the working pressure. The package is rated to 175 PSI.

Cooling between the stages is the whole point rather than a refinement: compressing cool air takes less work than compressing hot air, so the second stage runs cooler and the oil in a splash-lubricated pump stays in condition longer.

Will It Fit?

• Footprint. The unit measures 78" long by 28" wide. It is a horizontal package, so it wants a length of wall rather than a square of floor.
• Height. 55" overall. That is low enough to sit under a mezzanine, a duct run or a mechanical shelf that a tall vertical tank would not clear.
• Floor loading. 850 lbs dry, before oil and before the water that will live in the tank. Set it on a level slab, not on timber packers.
• Power. 208V, 3-phase. It will not run on single-phase service and it is not field-convertible to another voltage — the motor winding and the magnetic starter are specific to this part number.
• Circuit. Quincy’s own guidance for this model is to have a certified electrician size the breaker and the conductors. We publish that rather than a number, because the correct breaker depends on the run length and the local code as much as on the machine.
• Plumbing. The tank outlet is 1". Take your shop drop off the top of the tank, not the bottom, and slope the header away from the compressor.

Site preparation is the buyer’s responsibility. Confirming that you have 208V 3-phase service available at the intended location, that the slab will carry the machine, and that the electrical work is permitted and inspected where your jurisdiction requires it, all sit with you and your electrician. We are happy to talk it through before you order.

Protection that is already fitted

Three things on this machine exist purely to stop a bad day becoming a new compressor. The magnetic starter gives the motor thermal overload protection, so a stalled or overloaded motor drops out instead of cooking. The low oil cut-off switch stops the unit if the oil level falls far enough to put the bearings at risk — the failure mode that kills more shop pumps than anything else. The oil sight glass means checking the level is a two-second glance rather than a job that gets skipped.

Perfect For

• Independent service shops running impact tools, tyre machines and a paint booth off one system, where wet air is a quality problem and not just a nuisance.
• Fabrication and welding shops where plasma consumables and air-driven tooling are unforgiving about moisture.
• Buildings with a low ceiling or a full floor plan that can give up 78" of wall but not a tall vertical footprint.
• Sites already on 208V 3-phase service, which is common in commercial buildings fed from a wye transformer.

What is in the Box

The compressor as described: two-stage cast-iron pump, industrial motor, magnetic starter, horizontal receiver, finned intercooler, built-in air-cooled aftercooler with its variable-speed fan, automatic electronic tank drain, low oil cut-off switch and oil sight glass. Our data records this unit as supplied without an air dryer, so budget separately if you need dryer-grade air. The 3-year warranty extension is not included either — it requires the EWK-4 Maintenance Kit bought at the same time.

Specifications

Delivered air volume and motor current are on the manufacturer’s data sheet, and the figures held in our catalogue carry no units alongside them. Ask us and we will read both straight off the data plate for you.

Certification, stated plainly

The receiver is built to the North American pressure-vessel code and the unit carries a CSA mark. Our supplier data also references a North American third-party electrical listing, but that entry is not clean enough for us to badge it here, and we will not print a mark we have not confirmed. If your insurer or your municipal inspector requires a specific listing on the electrical package, ask us and we will confirm what appears on this unit’s data plate.

One thing to confirm before you order

Published details for the tank drain differ: Quincy’s feature list and the detailed specification on this page both state that an automatic electronic tank drain is fitted, while a summary field lists it as absent. If the automatic drain matters to your maintenance routine, ask us to confirm it against the shipping configuration before you order — we will check it with Quincy.

Shipping and delivery

This compressor moves as freight, not as a parcel, and it ships to the lower 48 states. The carrier delivers to the curb or the dock line; the driver is not responsible for getting the unit inside, so have a forklift or an equipment mover ready on the day. Terminal pickup is available and is often simplest for a shop without a dock.

Delivery to a residential address carries a residential fee. Tell us at the point of order if the address is a home or anywhere without commercial receiving, and we will quote it correctly rather than surprise you later.

Inspect the crate before you sign. Photograph dented sheet metal, a cracked skid or a shifted load, and write what you saw on the bill of lading before the driver leaves. A clean signed bill of lading is the carrier saying the freight arrived undamaged, and a claim after that is very hard to win.

Warranty

The compressor carries a 1-year factory warranty as standard, on both consumer and commercial use. That extends to Quincy’s 3-year "No Bull" warranty when the EWK-4 Maintenance Kit is purchased at the same time as the machine, and the extended cover includes on-site service and labour rather than parts alone. The unit has to be registered with Quincy for the extended term to apply.

One standing warning that applies to every compressor we sell: if you think you have a warranty failure, stop and call before you take anything apart. A pump that has been opened is a pump whose failure can no longer be diagnosed, and a disassembled unit is the most common reason a legitimate claim is refused.