Learn to install PC fans in this Eniun PC Lab practice. The PC already has a rear fan. Install a 120 mm front intake fan, connect it to CHA_FAN2 and check that the cable stays clear of the blades.
Components in this lab
- 120 mm front fan. Four-contact PWM cable, like the rear fan.
Safety and preparation
- Shut down and unplug the computer before opening the case.
- Wear a grounded antistatic wrist strap, as in the previous labs.
- The PC starts with the rear fan from the case assembly practice already installed. Here you add the front fan.
- Keep the motherboard manual nearby: it identifies the available slots and connectors.
Male and female connectors
In a pin connection, the male connector has protruding contacts and the female connector has sockets that receive them. In this practice, the end of the fan cable is a four-contact female connector. The motherboard header is male: its four pins fit into the holes in the cable connector.
Before connecting, check compatibility and align the connector guide with the header guide. Do not force it or rely only on colour. Handle the connection with the computer off and unplugged; when disconnecting it, hold the connector housing rather than pulling on the wires.
Why a PC needs airflow
The processor, graphics card and other components generate heat. Heat sinks transfer it to the air, and case fans replace the warm air with cooler air. Poor airflow can raise temperatures and make components slow down to protect themselves. The case fan works alongside the CPU cooler fan.
Which components need cooling
The CPU and GPU produce heat during operation. The RAM, chipset, motherboard power circuitry and storage drives also get warm. Their temperatures must stay within the manufacturer’s limits. Not every component needs its own fan: depending on the component and computer, cooling uses heatsinks, fans or the air circulating through the case.
Passive, active air and liquid cooling
Passive cooling dissipates heat without fans or pumps, for example using a finned heatsink and natural airflow. Active cooling uses devices that force circulation. With active air cooling, a fan moves air over a heatsink. In an active liquid loop, a block collects heat, a pump circulates coolant, and a radiator with fans transfers the heat to the air. “Active or passive” and “air or liquid” are different classifications; here we compare these three common examples.
Overclocking and heat
Overclocking means increasing a CPU or GPU’s operating frequency above its factory configuration to seek more performance. It can increase power consumption and heat, so temperatures, stability and cooling capacity must be checked. It does not always require liquid cooling or guarantee a sustained improvement. This practice does not perform overclocking or teach changes to frequencies or voltages.
Read more: computer cooling systems (Eniun, in Spanish).
Air intake and exhaust
In this case, the front fan draws air in and the rear fan exhausts it. This is a common layout, though the best arrangement depends on the case and its components. Set a consistent airflow direction and keep the air path clear. Adding more fans alone does not guarantee better cooling.
Check the arrows on the frame and the manufacturer’s instructions. One arrow may indicate blade rotation and another airflow direction. On many conventional fans, air exits on the side with the motor supports. Reverse-blade fans exist, so check the markings.
What three and four pins do
A three-pin fan has ground (GND), power and a speed feedback signal (tachometer, RPM). The RPM signal reports the speed. If the motherboard supports DC control, it can adjust the supply voltage to change the speed, including in response to temperature.
A four-pin fan adds a PWM control signal. The 12 V fan in this practice keeps its 12 V supply and receives the speed command on the fourth pin. PWM stands for pulse-width modulation. It controls the motor without varying the supply voltage.
A standard three-pin fan can fit a compatible four-pin header if you align the guide. The PWM pin remains unused. Select DC mode to control the speed if the motherboard supports it. Check the specifications for proprietary connectors and avoid forcing the plug.
Temperature, speed and noise
A fan curve links a sensor temperature to a requested fan speed. If the motherboard supports it, use BIOS/UEFI to select DC or PWM mode and set a profile. A balanced curve keeps temperatures under control without running the fans at full speed unnecessarily. A response delay can prevent frequent changes in noise.
This practice covers installation and connection. Set the fan curve and check temperatures on a real PC. The simulator does not measure temperatures or reproduce a BIOS.
CPU_FAN is for the CPU cooler fan. CHA_FAN headers are for case fans. Here we use CHA_FAN2 because the rear fan already uses CHA_FAN1. CHA_FAN3 would also work if it were free and within its electrical limit. The number identifies the header. On this motherboard, each CHA_FAN header supports up to 1 A (12 W). When using a splitter, add up the current drawn by all fans on that header. Check the manual for other motherboards or powered hubs.
Fan motor and lighting use separate connections. A lighted fan may need both. RGB and ARGB use different signals, voltages and connectors. Keep lighting cables away from CHA_FAN and avoid forcing similar-looking connectors.
Choose and secure a compatible fan
Check the fan size and mounting points, the available space in the case and whether its connection is compatible with the motherboard. Similar looks or matching colours are not enough. Here we install a 120 mm front fan with four screws: use all four mounting points and tighten without distorting the frame or forcing the threads.
Installation and maintenance
Secure the cable without tension and keep it out of reach of the blades. Keep intake and exhaust grilles clean and clear: adding more fans does not compensate for a blocked air path. If a cable rubs against the fan during testing, switch off and unplug the computer before moving and securing it; do not intervene while it is spinning. Hold the blades still during cleaning and follow the manufacturer’s instructions.
Lab sequence
Open the side panel, place the front fan and secure it with four screws. Connect the cable to CHA_FAN2. The simulator orients the fan for intake. Check the cable route and close the case.
The components are generic. Their connectors, dimensions and assembly sequence follow manuals for equivalent components and the motherboard. The 3D representation is an educational approximation.
Assessments
Test: installing PC fans
Your progress is saved only in this browser and is not sent to any server. Privacy and cookies
