Mitsubishi ceiling fan.

[Artisi]

I have a number of mitsubishi ceiling fans in the house, they are 4 speed controlled by a rotary wall mounted speed controllers.
1 of the units is now running very slowly on the lower speed. Other speeds are ok and it doesn't appear that it is mechanical, on shut down the fan rotates freely for what seems like a normal rundown period.

As yet I haven't looked at or checked anything but tomorrow I will open the rotary switch and have a bo-peep. I am assuming there will be contacts for each speed position and will be looking for dirty/ burnt / damaged contacts.

Any further ideas or suggestions for the low speed.
Thanks

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[ScottyUK]

Start with the easy stuff: swap the controller from one of the good fans, then you know whether you're looking for a fan problem or a controller problem.

 

[badservo]

If Scotty's plan rules out a bad controller then the fan may need a new capacitor.

 

[OperaHouse]

The simple controls are passive switching in one of several windings. There usually is a capacitor for a phase shift winding. That capacitor changing value would effect the lower speeds first. That would be very unusual, but I have a GE 10uF capacitor out of a furnace that measures 6.7uF. That is way beyond the 6% capacitor spec.

 

[Artisi]

Thanks guys; gives me somewhere to start.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Artisi]

Sorted, swapped controllers and the unit now runs at correct low speed. Re-installed the faulty controller to the donating unit, it now runs at low speed - but no problem as it only ever runs at high speed.
Thanks again.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[jraef]

If a component is failing in the controller, using it at all increases the risk of a fire.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[Artisi]

Thanks for the heads up, I forgot to mention that I will order a replacement - but the immediate problem is cured as the fan in question is highly utilised.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[crshears]

"Highly" or "Hardly"?

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[Artisi]

Highly, the original troublesome fan. The donating fan now with faulty controlker is rarely used and never at low speed.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)