Here is a clear, Marley-specific cooling-tower fan motor replacement guide. This applies to Marley NC, MCW, Series 1500, Series 3000, AV, Class 800, and most gear-driven Marley towers.
If you want, I can tailor this to your exact Marley model—just tell me which series you have.
✅ Marley Cooling Tower – Fan Motor Replacement Guide
Marley towers typically use:
* Gear-driven axial fans (right-angle Marley Geareducer)
* Marley Cooling-Tower Duty motors (TEAO/TENV, vertical shaft, long-life bearings)
The replacement process must preserve:
* Shaft alignment to the Marley Geareducer
* Fan pitch and load
* Motor support frame integrity
* Correct electrical and rotation setup
1. Preparation & Safety
✔ Lockout/Tagout (LOTO)
* Shut down tower fan, open motor disconnect, lock it, and test for zero voltage.
✔ Inspect Before Removing
* Note motor frame size, shaft diameter, mount pattern, RPM, HP, service factor, and enclosure type.
* Marley commonly uses 1750 RPM motors for gear-driven axial fans.
✔ Confirm new motor matches:
* HP/kW
* RPM (must match → different RPM creates incorrect fan pitch load)
* Frame size (e.g., 250T, 280T, 324T)
* Shaft height
* Rotation
* Enclosure: TEAO, TENV, or Cooling Tower Duty
* Space heater & RTD leads
2. Remove the Old Motor
A. Disconnect wiring
* Tag T1/T2/T3 and any auxiliary leads.
* Loosen conduit to free it from the motor junction box.
B. Uncouple from the Marley Geareducer
Marley machines use:
* Hollow-shaft motor couplings, OR
* Flexible grid couplings (Falk, Lovejoy type), OR
* Shaft-to-shaft spacer couplings on some models.
Steps:
1. Remove coupling guard.
2. Mark coupling half positions.
3. Remove bolts and separate the coupling.
4. Slide motor free from the input shaft side.
⚠ Important
Do NOT remove fan or gearbox during a standard motor change.
C. Lift motor out
* Use a chain fall or hoist.
* Remove motor hold-down bolts.
* Lift motor straight up to avoid bending the conduit.
3. Install the New Motor
A. Set the motor in place
* Ensure motor support channels (Marley "motor rails") are not rusty or flexing.
* Clean rails and apply anti-corrosion coating if needed.
B. Bolt motor loosely first
* Do not torque bolts until alignment is complete.
4. Align Motor to the Marley Geareducer
Proper alignment dramatically extends gearbox and bearing life.
Marley alignment guidelines:
* Parallel offset ≤ 0.005 in
* Angular misalignment ≤ 0.003 in per inch of coupling radius
* Motor shaft must be centered relative to gearbox input shaft
Use:
* Dial indicator
* Straightedge
* Feeler gauge
⚠ If using the Marley grid coupling:
Ensure the spacer piece fits freely without forcing; misalignment causes vibration and input-shaft seal failures.
5. Electrical Reconnection
* Connect leads per the motor nameplate (Wye/Delta or High/Low voltage).
* Reconnect space heater, RTDs, or thermistors.
* Seal conduit entries with watertight fittings.
6. Rotation Check
Before fully coupling:
1. Jog/bump the motor for 0.5 second.
2. Verify correct rotation:
* Induced draft towers → fan pulls upward
* Forced draft towers → fan pushes horizontally
If wrong:
* Swap any two power leads.
After correct rotation:
* Tighten coupling bolts or belt tension (if belt-driven Marley AV).
7. Final Steps
* Tighten all motor mount bolts.
* Reinstall coupling guard.
* Clear fan deck of tools.
* Remove LOTO and start the tower.
Monitor:
* Motor amps (must be ≤ nameplate × service factor)
* Gearbox vibration/noise
* Inlet bearing temperature
* Fan tip clearance
8. After 24 hours
* Recheck coupling bolts
* Check alignment again (temperature settling)
* Inspect gearbox input seal
* Verify motor amps under full load
* Confirm fan blade pitch has not shifted
