Coleman EB series

[FrenchRV]

We are fixing up our daughter’s mobile home to rent out. It’s a 2003 Fleetwood. The electricity has been cut off several times in the past few years for non payment. We have been doing a thorough cleaning from top to bottom including the central heat and air. My husband is real handy around the house. He took out the fan housing and cleaned it and put it back. It was very, very dirty. It had to be cleaned! We sprayed the coils with coil cleaner, we cleaned the floor registers, vacuumed the ductwork, bought new filters, and we even spray painted the return air duct vent cover and the cover on the unit itself. It’s a Coleman Electric EB series (EB -12B) air conditioning /heat pump unit. The inside unit is located in the hall and it almost looks like new now! We haven’t done anything with the outside part of the air conditioner yet. We now have the electricity turned on and we think we have a few issues and questions.

Now our questions:
We were a little surprised to find two air conditioning filters on each side (lying on the coils) when we took the cover off. The coils are on the diagonal and the filters don’t seem to fit exactly (too tall one way, not wide enough the other direction) we have never heard of using two filters. We found a slot at the top of the unit where a filter slides into (16 x 20 x1).
Above this slot is the open area where the return air vent is located.
So where should the filter/filters go?

The fan blades were very nasty. We have to wonder why and how they got that dirty?

When we turned the unit on for the first, we heard a sound like a vibration or maybe the fan blades where hitting something or something was loose. My husband readjusted the fan blades and it was better. But it is still making a slight vibration sound, what should we try now?

The unit front cover has a small vent on the upper portion of the front cover and there is a return air vent situated above the unit in the hallway and is it about a 14” X 14” square vent.
Why two vents?

Why does the front cover of the unit have a vent, doesn’t it need a filter to keep the coils and fan blades clean?

No one is living in the mobile home at this time, we have had some cold days just lately, when we are there working and turn on the heat, it doesn’t seem to blow out enough and the air doesn't seem warm. What should we do next?

The unit has always made to much noise, having to turn up the TV. The mobile home was new when it was bought and I think that the mobile home repairman has been out twice through the years but I am not sure about what he may have done if he did anything.

Any help would be appreciated.

[DaleM]

Can you post some pictures of the unit as well as the venting you describe?