How to Replace a Trane Rooftop Unit Pulley

The belt and pulley system of an RTU is vital to keep it running. Over time, adjustments or part replacements may be needed due to wear and tear. So if you’ve finished your diagnostics and determined it’s time to make the swap, you may be in need of some help. This guide for how to replace a Trane rooftop unit pulley will help get you through the repair and ensure your customer is satisfied with the work.

Supplies

• Drill and bits
• OEM replacement pulleys
• PPE (consult your work’s SOPs for required PPE)
• Wrenches
• Allen keys
• 3-jaw puller

Replacing the Pulleys

There are typically two pulleys in the Trane RTU. One is on the blower wheel and the other is on the motor.

• Step 1. Access the cabinet – To access the section of the RTU with the blower assembly, remove the panel.
• Step 2. Loosen the motor – The belt needs to be removed to take off the pulleys. To properly remove the belt, first loosen the bolts mounting the blower motor to give yourself some slack. 
• Step 3. Take off the belt – Carefully roll off the belt so it isn’t damaged.
  • Note: Inspect the belt to ensure it isn’t also worn out. If it’s damaged or torn, replace the belt.
• Step 4. Remove the wheel pulley – To remove the pulley mounted to the blower wheel, use an allen key to loosen it. Then either slide it off or use a 3-jaw puller for more difficult to remove pulleys.
  • Note: Be careful not to lose the set screw
• Step 5. Install the new wheel pulley – Slide on the new pulley. Ensure the set screw is properly lined up and then tighten everything with an allen key.
• Step 6. Remove the motor pulley – To remove the pulley mounted to the blower motor, use an allen key to loosen it. Then either slide it off or use a 3-jaw puller for more difficult to remove pulleys.
  • Note: Be careful not to lose the set screw
• Step 7. Install the new motor pulley – Slide on the new pulley. Ensure the set screw is properly lined up and then tighten everything with an allen key.
• Step 8. Reinstall the belt – Ensure the pulleys are properly lined up with a straightedge, and then install the belt back onto the pulleys.
• Step 9. Button up the unit – After the replacement is made, make sure the motor bolts are tightened and the panel has been reinstalled so the unit is ready to be put back into operation.