How to Fix an Overheating Air Compressor: A Troubleshooting Guide
When your compressor overheats, it results in costly downtime, so you want to handle the problem ASAP and prevent it from happening again. This troubleshooting guide identifies the signs of an overheated air compressor, helps diagnose common causes and provides actionable steps to fix the problem, so your operation can quickly return to business as usual.
This guide primarily addresses oil-flooded rotary screw compressors, but can be applied to most industrial air compression technologies.
How Can I Tell if My Air Compressor is Overheating?
When an air compressor runs hot, it can reduce the life of the oil, increase loads on compressed air treatment equipment or completely shut down. There are a few ways to tell if your compressor is experiencing overheating.
Check the Control Panel: The control panel will show the operating temperature and most control panels will display warnings or fault codes if the compressor shuts down. A tripped circuit breaker could also be an indication that the compressor is overheating and is consuming too much power as a result.
Monitor for High Temperature: Optimal air-end discharge temperature for oil flooded rotary screw compressors is usually 185-190°F. Oil life may be reduced if the temperature exceeds 200°F and the compressor may automatically shut down if it hits 220-230°F. The compressed air discharge temperature out of the compressor package should be below 100°F. Your compressor manual will offer precise guidance regarding optimal temperatures for your model.
What Does a Burning Smell Mean?
The smell of burned oil, or if the oil has a varnish smell, is a critical warning sign that requires immediate shutdown of the compressor and an inspection to prevent catastrophic failure.
What are the Common Causes of an Overheating Compressor
Several issues may be responsible for an overheating compressor, including:
Inadequate ventilation: Poor ventilation or blocked ducting can cause a compressor to overheat. Compressor room ventilation should be able to remove the heat from the room, even when all the equipment is running at 100% capacity.
If the compressor cooler is ducted, ensure that it doesn’t restrict the compressor’s cooling fan flow. If it does, a booster fan may be required in the ducting. Provisions in the ducting may be needed to prevent freezing temperatures from getting into the compressor during winter months, and heat recovery to send heat from the compressor room into the building during winter may be beneficial.
Inadequate space around the compressor can also restrict airflow, so be sure there is enough space around the unit to enable airflow and maintenance activities.
High ambient temperature: When the air in the compressor room is too hot for air cooled systems to effectively cool themselves, overheating will occur. The solution may involve improving ventilation, using a water-cooled compressor or other means to remove excess heat from the room.
Insufficient or degraded oil: Low oil or oil that has varnished can result in overheating, as well as compressor wear and tear. Be sure to check the compressor’s oil level often, take oil samples and follow the manufacturer’s maintenance recommendations for oil change frequency.
Old or clogged components: If coolers, oil filters or separator elements become clogged, overheating can occur. These components should be serviced or replaced periodically to avoid problems.
Defective thermal valve: If the thermal valve is stuck in the wrong position, it can prevent oil from reaching the cooler, leading to overheating issues with the compressor. Because the valve may need replacement during the lifetime of your compressor, it may be beneficial to keep a replacement valve in stock.
Frequency of use: If adequate cooling capacity is available to the room and you’re doing a good job maintaining the compressor, overheating should not occur, even if it runs 24/7. Proper installation and proactive maintenance and monitoring the operating temperature of your compressor will help reduce wear and tear and instances of overheating.
How to Fix an Overheating Air Compressor and Prevent Reoccurrence
Fixing an overheating air compressor and preventing it from happening again is a multi-step approach. First, always follow the instructions in your compressor’s manual. Below is a general outline of what may be required.
Step 1: Safely Cool Down a Hot Compressor
1. Do not immediately restart the compressor if it has shut down due to high temperature.
2. Safely perform a shutdown procedure.
3. Allow the unit to cool down completely.
4. While the compressor is off, visually inspect the area for obvious blockages around air intakes and coolers.
Step 2: Troubleshoot and Fix the Root Cause
For Inadequate Ventilation: Check for and remove any obstructions around the compressor. Ensure that ducting is not blocked and verify that ventilation fans are operating correctly.
For Oil Issues: Check the oil level via the sight glass and top it off, if needed. Take an oil sample. If the oil appears abnormally discolored, smells burnt or varnished, schedule an immediate oil and filter change. If an oil change doesn’t solve the problem, it may indicate that the coolers need to be cleaned internally or replaced.
For Clogged Components: Use compressed air at the recommended pressure and direction to blow out dust and debris from the cooler fins of externally clogged, air-cooled compressor coolers. Check the pressure drop across filters and separators via the control panel or gauges. If high, replace the elements.
Step 3: Implement a Proactive Maintenance Schedule
Preventing future issues with overheating is essential to compressor and facility uptime. The following inspections should be performed on a routine basis as advised below:
Daily Inspections
- Check control panel temperatures.
- Check control panel for alarms or warning lights.
Weekly Inspections
- Inspect and clean coolers by air jet, if needed.
- Inspect ventilation system to ensure it is not blocked.
- Check for pressure drop over the filters.
Routine Service (follow manufacturer’s recommendations for frequency)
- Check and change oil, as recommended.
- Inspect air inlet filters for cleanliness or damage, replace if needed.
- Check and change separators, if needed.
Your Partner in System Reliability: Contact JHFOSTER for Compressor Service
While these steps can solve common issues, service from a certified technician may be needed if the compressor continues to run hot or overheat. JHFOSTER offers 24/7 emergency service, certified technicians for all major brands and comprehensive system evaluations to improve long-term efficiency and prevent future downtime. Request service and repair, contact us, call 855-688-0065 or email us at solutions@jhfoster.com for assistance.
