Glycol chillers keep processes running in industrial environments like food and beverage, pharmaceuticals, plastics, data centers, and more. When they develop problems, the consequences are often temperature drift, production slowdowns, and unplanned downtime— all things that can cost you more time and money to remedy.
Most glycol chiller problems follow the same patterns. This article will cover the most common problems we see, along with practical steps to diagnose and troubleshoot each one.
Note: If you need assistance with your Delta T Systems chiller or other equipment, our support team is here to help. Call toll-free: (800) 733-4204.
1. Glycol Chiller Not Cooling Properly
Potential Causes:
- Low or incorrect glycol concentration reduces heat transfer capacity and freeze protection
- Fouled evaporator or heat exchanger surfaces (scale, biofilm, or mineral buildup)
- Degraded glycol that has oxidized or lost its inhibitor package
- Refrigerant charge issue reducing chiller cooling capacity
Troubleshooting Steps:
- Test glycol concentration: Use a refractometer to verify the glycol-to-water ratio. If it has dropped due to unintentional water additions, correct the concentration and retest.
- Inspect heat exchanger surfaces: Scale or biofilm on evaporator surfaces insulates them and blocks heat transfer. Clean and treat as needed.
- Evaluate fluid condition: Discolored, foul-smelling, or acidic glycol should be replaced. Aged fluid loses its inhibitor package and accelerates corrosion.
2. Flow Rate Alarms or Low Flow Conditions
Potential Causes:
- Clogged strainers or filters restricting pump inlet flow
- Air trapped in the system
- Glycol over-concentration increases fluid viscosity
- Pump wear or impeller damage
- Undersized piping or long line runs, creating excessive pressure drop
Troubleshooting Steps:
- Inspect and clean strainers: Remove and clean clogged strainers or filters. This is the most common and easiest fix for low-flow conditions.
- Bleed the system: Use the manual or automatic purge to eliminate trapped air from the loop.
- Check glycol concentration: Overly concentrated glycol becomes more viscous, especially at low temperatures, making it harder to pump. Verify the mix ratio with a refractometer.
- Assess pump condition: Listen and look for cavitation noise, vibration, or low flow alarms. Check impeller condition and verify the pump is rotating in the correct direction.
- Review system pressure drop: For facilities running glycol across multiple zones or long line runs, centralized cooling infrastructure can reduce pump strain. Delta T Systems’ industrial central chillers are sized for plant-wide distribution.
3. High Temperature Alarms
Potential Causes:
- Faulty temperature sensor or thermocouple providing inaccurate readings
- Blocked return flow preventing proper heat removal
- Fouled condenser reducing heat rejection capacity (air-cooled units)
- Incorrect setpoint or controller settings
Troubleshooting Steps:
- Validate sensor readings: Cross-check with a secondary temperature probe or calibrated thermometer to confirm whether the alarm reflects actual temperature or a sensor fault.
- Inspect return lines: Look for restrictions, kinked hoses, or check valves stuck in the closed position that are blocking return flow to the chiller.
- Clean the condenser: On air-cooled units, check that the condenser fins are clean and airflow is unobstructed. Dirty condensers are a leading cause of high-pressure and high-temperature faults.
- Reset and reprogram: Power cycle the unit and confirm all controller setpoints and operating modes are correctly configured.
4. Fluid Leaks
Potential Causes:
- Worn or damaged pump seals
- Loose hose connections or fittings
- Cracked heat exchanger or piping caused by freeze damage
- Corrosion from degraded, acidic glycol attacking metal components
Troubleshooting Steps:
- Inspect pump seals: Look for dripping at the pump seal. Replace worn seals promptly to prevent fluid loss and pump damage.
- Check all connections and fittings: Tighten loose fittings and replace any hoses showing cracks, abrasion, or soft spots.
- Look for freeze damage: If the system experienced a freeze event, inspect heat exchangers and piping for cracks caused by ice expansion.
- Test glycol pH: Acidic glycol actively corrodes metal components. If corrosion-related leaks are appearing, a full fluid replacement is needed before replacing parts.
Additionally, when water/glycol quality is questionable, we recommend contacting a water treatment specialist to assess current water/glycol quality to prevent biological growth and fluid contamination.
When Troubleshooting Isn’t Enough: Evaluating a System Upgrade
Some glycol chiller problems are signs that a chiller system has reached the end of its effective service life, was undersized for current process demands, or was never configured for the actual operating environment. When maintenance costs are climbing, cooling capacity no longer meets demand, it may be time for an upgrade.
Delta T Systems designs and manufactures industrial process chillers, industrial central chillers, and custom-engineered cooling solutions for applications where standard platforms aren’t enough. Our engineering team will assess your thermal load, operating conditions, and glycol system requirements to specify a solution that’s the correct size for your application from day one.
Dealing with a glycol chiller issue and not sure where to start? Contact Delta T Systems today — our team is ready to help and recommend the right solution for your process.