I have a Gooman heat pump system and I was going to clean my filter from the furnace unit in basement and can not get it out. It seems to be caught on something and restricting it from sliding out. I have had trouble before but I could eventually get it out as I clean it twice a year. The unit is 5 yrs old, it is a slide out plastic filter that can be washed and reused, it is a black frame with blue mesh for the filtering. Is there a panel I can take apart to see what's holding it from coming out? I may have put it back in upside down last time I cleaned it, not sure what to do.