Hello-
I was changing the filters in my mom's furnaces in her house. When I got under the crawlspace, the furnace filter cover says that the filter is a permanent type. There was no filter in it at all and I need to know what kind goes in it. It is a ruud model #RCBA 2457GG14 with a serial # M1802. Amy help would be appreciated. Thank you.
Charles

I, would take a close measure with a rule or yardstick and see what size fits the whole or slot ,is not a good thing to run for very long without a filter,can plug up an evaporator coil,gets way too much dust and filth around the blower motor,, I kind of like the cheap filters,and replace every 30 days myself, some might not agree but regular habit of changing will keep you from forgetting, and a dirty,clogged filter is a bad thing also.for around 10 bucks,you can buy enough to last a year,, the so-called perminate filters still have to be removed and cleaned,

Charles, I had the same question in my mind. Why does it say there is a permanent filter installed, but it is no where to be found? I am calling the Ruud dealer and asking what is going on, as the coils in the unit are loaded with dirt, etc. I do have a filter that I change monthly, but I did not know about this one under the unit. My a/c was installed about 5 or 6 years ago in a brand new home and I just found out about this while investigating another problem with the condensate drain. Joanne

It takes a 12x20x1