How to Install Filter Fans Correctly
How to Install Filter Fans Correctly | Charter Controls Thermal Management
Summary:
Correct installation of filter fans is essential for reliable panel cooling. This guide explains airflow direction, heat zones, dust build-up, and why the Linkwell LK32 hinged-grille design makes maintenance fast and reliable.
🔥 Why Filter Fans Fail More Often Than You Think
At Charter Controls, we take weekly calls from panel builders experiencing overheating panels even though filter fans are installed.
In almost every case, the root cause is not the fan itself, but incorrect installation, blocked airflow paths, mismatched fan directions, or uncontrolled heat zones.
Filter fans are extremely effective when installed correctly — but they rely on natural convection, clean airflow paths, and a logical hot-to-cold flow through the enclosure.
💧 Principle 1: Always Pull Cool Air In From the Bottom
Heat naturally rises. Your cooling strategy should reinforce this, not fight it. A typical panel should be configured as follows:
- Filter fan (intake) at the bottom pulling cool ambient air into the enclosure.
- Exhaust grille at the top to expel rising warm air.
- No fans blowing downward, sideways, or across each other.
Installing fans high up on the panel blowing inward will force hot air downward, opposing convection and trap heat around drives, contactors, and power supplies.
💨 Principle 2: Ensure a Clear Airflow Path
Even with the intake and exhaust correctly positioned, airflow can collapse if:
- Cable bundles block airflow between intake and the hottest components.
- DIN-rail equipment is too tightly packed.
- Multiple internal partitions restrict air movement.
- Heatsinks of drives or power supplies face away from the airflow path.
Think of the airflow as a “cooling tunnel”: air must travel from intake to exhaust without obstruction.
📿 Principle 3: Never Install Fans That Fight Each Other
Another common design errors is:
- A bottom fan blowing in
- A top fan also blowing in
- No exhaust path
When fans oppose each other:
- Static pressure rises inside the panel.
- Airflow stops or reverses unpredictably.
- Hot zones become hotter and equipment derates or fails.
Only one fan should be actively pulling air in.
The opposite side should be passive exhaust or a dedicated exhaust fan.
🔩 Principle 4: Understand Panel Heat Zones
Different components generate very different levels of heat. In panel thermal design, the top 30% of the enclosure is typically the hottest zone.
Major heat contributors include:
- AC Drives / VFDs (largest heat producers in most panels)
- Switch-mode power supplies
- Soft starters
- Contactors and motor starters
- PLC CPUs and HMIs (mild but still relevant in compact enclosures)
Because of this, cool air must enter at the opposite end of the enclosure and pass these high-power devices on its path upward.
🧹 Principle 5: Dust Restricts Airflow — Regular Maintenance Is Critical
Even the best cooling system fails when dust builds up. Dust creates:
- Reduced airflow
- Higher static pressure
- Hot spots around power electronics
- Premature derating of drives and power supplies
For this reason, filter mat replacement must be routine, especially in dusty workshops or outdoor sites.
Linkwell’s LK32 series filter fans make this easy with their:
- Hinged front grille for tool-free access
- Simple slide-out filter mat
- Durable ABS housing (RAL7035)
Technicians can replace a filter mat in seconds — no screws, no disassembly, no downtime.
💡 When to Use an Exhaust Fan (Instead of Passive Exhaust)
An active exhaust fan is recommended when:
- The enclosure is large or tall
- Airflow path is long or obstructed
- Ambient temperature is high
- Internal heat load is significant (VFD-heavy panels)
In these cases, pairing a bottom intake fan with a top exhaust fan creates a controlled, reliable flow.
🛠 Recommended Products
📞 Need Support?
If you are experiencing overheating issues or uncertain airflow patterns, our technical team can help.
Phone: 01424 850660
Email: enquiries@charter-controls.com
Contact: https://www.charter-controls.com/contact/contact.aspx
Frequently Asked Questions
Q: Should the filter fan blow in or out?
A: Always blow inward at the bottom of the panel and exhaust upward. This reinforces natural convection and prevents hot-air trapping.
Q: How often should I replace the filter mat?
A: In clean environments, every 3–6 months. In dusty workshops, weekly or monthly. The LK32 hinged grille makes this fast and simple.
Q: Can I use multiple fans?
A: Yes, but only if they reinforce the same airflow direction. Never mix intake and intake, or exhaust and exhaust, or fans will fight each other.
Q: When should I use enclosure air conditioning instead of filter fans?
A: When ambient temperature is high or when internal heat loads (drives, power supplies) exceed what passive airflow can remove.