MaxxFan 4751ks Will Start For A Few Seconds Then Fan Stops And Lid Closes

Updated 08/13/2024 | Published 08/10/2024

Products Featured in This Question

Replacement Rain Sensor for MaxxAir RV or Trailer Roof Vent Fans

(58)

$21.85

Question:

We have the MaxxFan 4751ks in our RV bathroom, which has the wall control panel. When the fan lift switch is pressed, the fan lid will go up. When a fan speed switch is pressed, the lid will go up, the fan will start for about 2-3 seconds, then stop and the lid lowers. I searched online and also talked to a tech at AirExcel, who said it was the circuit board. I ordered a new one whole new and expensive story and after install of the new board, the fan is acting exactly the same way....it didnt solve anything and Im out $150! Im not sure where to go next....any suggestions? Thanks in advance for any assistance.

asked by: Glen

Expert Reply:

Hello Glen, thanks for reaching out. If the circuit board did not fix the issue, it could be the rain sensor that is causing the problem. Something triggering the sensor will cause the lid to close so that would explain it. The best way to test this is to simply disconnect the rain sensor and see if the vent starts to work normally. If disconnecting the rain sensor allows things to work, you will need to replace it with part # MA34FR.

expert reply by: Jesse M

Glen

8/13/2024

Thanks Jesse, for the note. Just so you are aware, there is no rain sensor on this 4751KS. I have checked and activated the operator and it seems fine (can be rotated without slipping. That only leaves the lid opening motor as a suspect. Cheers Glen

Jesse M.

8/13/2024

@Glen Oh ok well we can rule out the rain sensor then! The motor is really the only other functional component of the vent that could potentially cause the issue you are describing. it is not unheard of for the motors to go bad. Usually when the motor goes, the lid will not open or close at all. You could try disconnecting the mechanical links from the motor and see if it turns normally. The new motor is part # MA10-20270. The operator mechanism is part # MA10-20281K-1AF but you should be able to tell if the operator mechanism works normally or if the motor itself is the issue.

Glen

8/13/2024

@JesseM thank you for the quick response. There is only so many moving parts in this unit, so I'll try a new motor, as you suggest. It's getting to the point where it's almost cheaper to buy a whole new fan unit, rather than replace parts but I'll give it one more try. thanks again. Glen

Jesse M.

8/13/2024

@Glen I hear you there, Glen. Some of these parts are not cheap. At this point the motor is really the only part left that could be the culprit. Have you already verified that the vent is getting its full 12V power? That is something worth checking if you haven't already. Do let me know how it goes!