I have mears 240 volt double pole[m602] thermostats in my house for my celling heat.They have been in for 23 years. They work great.except they have become very hard to turn the dial.Any [email protected]

Replacement is one option or I have used a dry teflon spray to free up controls.

Teflon Spray, RTV Silicone Adhesive

Lowe's has the one below. The tricky part is being able to get it into the control itself but I always manage and when you are done it will be so smooth you will ask yourself why you did not do it sooner. PS turn off power first and let set for 15 minutes after spraying.