Common questions. Practical answers.

The chiller can operate with water or an approved water/glycol solution, depending on the application and operating conditions. Glycol is commonly used where the fluid may be exposed to freezing temperatures or where the required leaving-fluid temperature approaches or falls below the freezing point of water. The glycol type and concentration should be selected for the expected operating and ambient conditions. Keep in mind that increasing glycol concentration changes heat-transfer performance, pressure drop, and required pump performance.

Generally, no. Use a glycol product specifically intended for HVAC, process cooling, or heat-transfer applications and compatible with the system materials. Automotive antifreeze contains additives formulated for automotive engines and may not be appropriate for the chiller's heat exchanger, pumps, seals, or piping system.

A chiller cools a circulating fluid typically water or a water/glycol mixture which is then pumped to the process or building load. A condensing unit is part of a direct-expansion refrigeration system and generally provides the compressor and condenser portion of the refrigeration circuit while an external evaporator handles the cooling load.

Propylene glycol in a chilled water system doesn’t “expire” on a calendar date, but its protective performance can degrade. In a well-maintained, inhibited system, it can last decades, but in untreated or poorly maintained systems, it may need replacement within a few years to avoid corrosion, fouling, and loss of freeze protection.

To determine if your propylene glycol solution is still effective, regularly check

Glycol concentration (to ensure freeze point and viscosity are correct)

Freeze point (should match system requirements)

pH (should be in the inhibited range, typically 6.5–8.5)

Conductivity (to detect contamination)

Clarity and color (to spot deposits or corrosion products)

Condition of corrosion inhibitors (via lab testing)

Technically... no but that's what we tell the sales department.

A chiller doesn't actually "make cold." It moves heat. The refrigeration system removes heat from the process fluid and rejects that heat somewhere else typically to the outdoor air through the condenser.

The fans will ramp up, down, or not at all accordingly to maintain the condensing saturation set point (typically 110-112°F.)

The pump, condenser fan, and compressor all need to be enabled when first powered up. Also, check for any possible system alarms that may be preventing the motors from running.

A made flow switch indicates enough flow to protect the chiller barrel or plate exchanger from icing up and rupturing. It does not indicate enough flow needed for its designed operation.

Not necessarily. When a compressor is unloaded or the hot gas bypass is engaged, it is common for there to be bubbles in the sight glass. The system needs to be evaluated as a whole to determine if the refrigerant charge is adequate or not.

Not necessarily. If you're having head pressure alarms and the condenser fan operation has been verified and no refrigerant has been added in recent time, there's a very good chance that the condenser coil is dirty. Sometimes, this means rinsing the condenser more than once.

Refer to the chiller nameplate and electrical documentation. You will typically see MCA, MOCP, and SCCR listed. These values serve different purposes:

1. MCA — Minimum Circuit Ampacity: The minimum required ampacity of the conductors supplying the equipment. MCA is used when determining the minimum allowable branch-circuit conductor size.

2. MOCP — Maximum Overcurrent Protection: The maximum permitted rating of the upstream fuse or circuit breaker protecting the equipment. The installed overcurrent protective device must not exceed this value.

3. SCCR — Short-Circuit Current Rating: The maximum available fault current the equipment can safely withstand when installed and protected as specified. The available fault current at the installation location must not exceed the equipment's SCCR.

Always use the unit nameplate, supplied electrical drawings, applicable electrical code, and local requirements when sizing conductors and overcurrent protection.

The required voltage, phase, frequency, MCA, and MOCP are identified on the equipment nameplate and electrical drawings. Verify the available facility power matches the unit requirements before energizing the equipment.

It depends on the electrical design of the specific unit. Many industrial three phase chillers require only three phase power and an equipment grounding conductor, while others may require a neutral for specific loads. Always refer to the electrical schematic and incoming power connection details for the specific unit.

The chiller is equipped with a hardwired remote enable/start input. From the factory, a jumper is installed across the remote-enable terminals, allowing the chiller to operate from its local controls. To control the chiller from a remote control system, remove the factory jumper and connect a set of dry contacts to the designated terminal blocks.

Yes. The chilled water temperature setpoint is adjustable from the LCD/HMI located on the chiller control panel. Depending on the unit configuration and options provided, additional operating parameters, alarms, status information, and setpoints may also be available from the display.

Normally, no. Control power is typically derived internally from the incoming chiller power supply. The control panel provides the required control voltages for the PLC/controller, relays, sensors, and other control devices. Any required external control power will be clearly identified on the electrical drawings.

Yes, dry contact outputs are provided for signals such as General Alarm. This alarm contact is typically landed at terminals C and D.

Yes. BACnet and/or Modbus communications are available as options, depending on the control package selected. These interfaces allow a BMS, PLC, or other supervisory system to monitor operating conditions, alarms, temperatures, pressures, and other available data points.

An embedded web server may also be provided, allowing authorized users to remotely view chiller operation through a web browser, essentially giving you a remote view of what you would see while standing in front of the chiller.

This depends on the communications package and how the controls are configured. Certain parameters can be made available as read/write points, while others may intentionally remain read-only.

The chiller's primary refrigeration and equipment-protection controls operate locally and do not normally depend on the BMS connection to safely control the refrigeration system.

Yes. Depending on the selected controls package, alarms can be made available through BACnet, Modbus, Ethernet, dry contacts, and/or the embedded web interface. Available information may include active alarms, operating status, temperatures, pressures, compressor status, pump status, and other system conditions.

Receiving a start command does not necessarily mean the compressor starts instantly. The controller first verifies that required permissives and safety conditions are satisfied. The unit may also incorporate anti-short-cycle timers, water/glycol flow proving, pressure checks, temperature conditions, staging delays, or other protective sequences before allowing a compressor to start.

No. The main disconnect or circuit breaker is intended for power isolation and overcurrent protection, not normal operating control. Normal starting and stopping should be performed through the chiller controller, local controls, or designated remote enable/start circuit.

It is preferred for motors to be disabled through the controller. Refer to the appropriate equipment manual for the procedure.

No. The root cause of an alarm will not simply go away on its own. At a minimum, pictures should be taken of the alarm before clearing the alarm via the controller. Typically, a reputable commercial air-condition/ refrigeration service contractor should be called out to diagnose and resolve the condition.