How to Maintain an Oil Temperature Controller for Long-Term Use

An oil temperature controller (TCU) is the backbone of precision temperature management in industries like plastic molding, chemical processing, and laboratory testing. Neglecting maintenance can lead to erratic temperature control, component failure, or even safety hazards. To keep your TCU running reliably for years, follow this comprehensive maintenance guide.

1. Daily Routine: The Foundation of Longevity​

Consistent daily checks prevent small issues from escalating into costly breakdowns. Start by verifying the oil level through the sight glass—low levels cause sensor misreads and pump damage, while overfilling risks pressure buildup . Next, inspect for leaks: check pipeline connections, seals, and valve joints for oil stains, as even minor leaks degrade performance over time .​

Monitor operational parameters closely. A stable TCU should maintain temperature within ±1°C of the setpoint; fluctuations beyond this may signal sensor drift or oil degradation . Listen for unusual noises from the pump or heater—grinding sounds often indicate worn bearings, while humming could mean electrical issues . Finally, keep the exterior clean: wipe dust from vents and control panels with a dry cloth to ensure proper heat dissipation .

2. Thermal Oil Management: The Lifeblood of Your TCU​

Thermal oil degradation is the leading cause of TCU failure, so proactive oil care is non-negotiable. First, always use manufacturer-approved oil—mixing different grades creates sludge that clogs lines and damages heaters .​

Know when to replace oil by combining three indicators:​

• Appearance: Dark, cloudy oil or visible sediment means oxidation has occurred .​

• Performance: If heating takes 20% longer than usual or temperature swings increase, oil efficiency has dropped .​

• Schedule: For lab use (2–4 hours/day, ≤200°C), replace every 1.5–2 years; industrial high-heat use (8–12 hours/day, ≥250°C) requires changes every 6–12 months .​

When changing oil, drain the system completely and flush the tank with a manufacturer-recommended cleaner to remove residue . Never reuse old oil, even if it looks clean—hidden contaminants accelerate wear.

3. Core Component Care: Sensors, Actuators, and Electronics​

Each TCU component has unique maintenance needs that directly impact accuracy and lifespan.​

Temperature Sensors​

Sensors like PT100 probes are critical for precise readings. Every quarter, calibrate them using a multimeter: at 0°C, resistance should be 100Ω ±0.1Ω . Regularly clean the probe with a soft brush to remove oil buildup, which distorts measurements . Ensure sensors are installed in oil flow-rich areas—avoid air pockets or dead zones that cause false readings . If your TCU shows "HHH/LLL" errors, check for loose wiring or sensor damage .​

Heaters and Cooling Systems​

Heaters fail when oil contaminants burn onto their surfaces. Inspect heating elements annually: look for carbon deposits and use a non-abrasive tool to clean them . Test for short circuits with a multimeter—replace elements if resistance is abnormal .​

For cooling systems, clean condenser fins monthly with compressed air (keep pressure below 0.3MPa) to prevent overheating . Replace dry filter every 4000 hours, as saturated filters reduce cooling efficiency by 60% .​

Electrical System​

Tighten wiring connections every three months to prevent overheating from poor contact . Check 继电器触点 for 碳化 —if resistance exceeds 0.5Ω after 2000 hours of use, replace the relay . Use an infrared thermal camera to scan terminals: a 15°C temperature difference between connections signals a problem .

4. Preventive Maintenance: Avoiding Catastrophic Failure​

Preventive steps reduce downtime by addressing issues before they cause breakdowns.​

• Filter Care: Clean inlet filters monthly (weekly in dusty environments) to prevent clogging, which strains the pump .​

• Leak Testing: Use a pressure gauge to check for system leaks quarterly—drop-offs in pressure indicate seal damage .​

• Vibration Monitoring: Install vibration sensors on pumps; readings above 4mm/s signal bearing wear .​

• Environment Control: Keep the TCU in a dry, ventilated area with temperatures between -20°C and 70°C . Avoid direct sunlight, which accelerates plastic component aging .​

5. Troubleshooting Common Issues​

Even with maintenance, problems arise. Here’s how to address frequent issues:​

• Temperature Fluctuations: Check for bad earth(add a shielded cable if needed) or dirty filters .​

• Heater Not Working: Verify the relay has 12VDC output and inspect for wiring errors .​

• Oil Leaks: Replace worn O-rings and gaskets—use only manufacturer-approved parts .​

• Keep a maintenance log tracking oil changes, calibrations, and repairs—this identifies wear patterns .​

• Upgrade aging systems with redundancy: add a backup mechanical thermostat set 5°C above the main controller .​

• Train operators to avoid frequent start-stop，which stresses components .​