Advantage OACS Series Central Chillers

Power and process piping only — OACS units ship fully charged and tested, ready to set on an outdoor pad. There's no mechanical room, no cooling tower and no plant-water connection to plan for.

Dual-zone units make sense when two process loops genuinely need independent temperature setpoints running at the same time. If only one temperature is needed, or the two loops don't run concurrently, a single-zone unit (or two independent single-zone units) is usually simpler to size and service.

It's the one real construction break in the line: a rotary Screw compressor, a shell-and-tube evaporator and a stainless-steel reservoir on R-513A refrigerant, versus the brazed-plate evaporator, polyethylene reservoir and R-454B used across every smaller OACS model. Plan its service and spare parts separately from the rest of the line.

Single-zone (S-suffix) models use the OACS-MG manual; dual-zone (D-suffix) models use a separate OACS dual-zone manual. Check the specific PN page for your model — the correct manual differs by configuration, not by tonnage.

Advantage calls for at least 4 ft between every side of a single-zone OACS unit and any wall or obstruction, and no overhead obstructions at all. Units placed side by side need 8 ft between them; end to end, 4 ft. If the unit sits in a pit or is walled in, the top of the condenser must be level with or above the top of the pit, with 8 ft to the pit walls. Screening fences or louvers need at least 80% free area and 4 ft of clearance, and must not be taller than the unit. Set it on a level concrete pad rated for the operating weight.

More often than an indoor chiller does. Advantage requires a water and inhibited propylene glycol mix whenever the setpoint is 48°F or lower or the unit could see ambient temperatures under 35°F. Mix it to protect to the lowest expected ambient or 25°F below the lowest setpoint, whichever calls for more glycol, and verify the mix with a refractometer. Don't hook up the optional automatic water make-up in a climate that freezes, because it would dilute the glycol. On the refrigerant side, EC fan speed control and pressure-staged fans hold head pressure down to -20°F ambient.

The model number shows the pump set: 1P is a single process pump, 2P adds an evaporator recirculation pump, 3P adds a standby pump, and APT means no integral tank or pumps, for sites that already have a reservoir. The process pump is sized at a nominal 2.4 gpm per ton. Single-circuit units use Advantage's MG instrument; dual-circuit units use the MZC III, with a zone board per circuit. Both include Modbus RTU or SPI, and Modbus TCP is optional. Other options include drain-back prevention for overhead piping, supply and return isolation valves, an automatic low flow bypass valve and a main disconnect.