One of my Mitsubishi 4 speed, wall mounted rotary speed control fans is running slow on lowest speed - other speed can't really be sure if running at their design speed. 

 

I have a second unit with the same problem but of no consequence as it always run on either 2 or 3 setting. 

 

What / where should I be looking. 

Thanks 

First check would be your house electric voltage (if 180 rather than 220 can make quite a difference) - if voltage is low the fans will run slow as the speed is controlled by the voltage.  As more than one unit shows this expect voltage is the reason.  You can obtain multimeters for about 200 baht if there is nobody that can check.

3 minutes ago, lopburi3 said:

First check would be your house electric voltage (if 180 rather than 220 can make quite a difference) - if voltage is low the fans will run slow as the speed is controlled by the voltage.  As more than one unit shows this expect voltage is the reason.  You can obtain multimeters for about 200 baht if there is nobody that can check.

Thanks - 

can rule that out, other fans on the same circuit are fine. 

I'm thinking start /run capacitors - but not being a sparkie I'll take advise from others. 

Yeah, look at the capacitors (cheap, just replace) and possibly the bearings if they are of the sleeve/sintered variety.

6 minutes ago, Crossy said:

Yeah, look at the capacitors (cheap, just replace) and possibly the bearings if they are of the sleeve/sintered variety.

Thanks