Timer can turn on but not turn off the filter?

[shinachen]

The filter timer was set from 10am to 2pm on high and from 7pm to 8pm on low. However, I found that recently, the filter can start on the set time but it can not stop on the set time. What's wrong with it? I just moved in this house and does not have the manual for the filter.

I am in Texas. It is super hot recently. Is it possible due to some temperature sensor? So, when it is hot, it will keep running?

 

[Isaac-1]

What type of timer do you have? Brand Model? If you don't know can you post a photo?

 

[alanpaul]

Shinachen,
Many manuals are also available online, so if you can identify your manufacturer and your model number on the timer, you may be able to locate the manual without too much difficulty. Most companies let you download their manuals to your computer.