AC tonnage determination

[nmbexcuse]

Hi I posted a thread last week about different technicians trying to determine the tonnage of my AC units and they came up with different numbers. Here are the unit models:

(1) Janitrol Model CKL 36-1D

(2) This one is a bit tricky because part of the label has torn off, leaving only part of the model number visible. The manufacturer is Rheem and it's model RAF8-04..........can't read the rest. However, after the digit "4" the next digit seems to be a "2" because I see part of the "2" in the lower left hand corner, I think it's a "2".

Another question is I noticed the Rheem unit has a main return in the hallway, but each of the four bedrooms has their own 10"x10" return and vent. I don't remember seeing an central AC system with so many returns. The main return needs a 23"x17" filter and each of the 4 room return require a 9"x9" filter. Is it efficient to have so many returns?

Thanks,

MC

[<kjpro]

36,000 Btu, which is a 3-ton unit.

If it&#39;s a 2, its 42,000 Btu, which is a 3 1/2-ton unit. If it&#39;s a 8, its 48,000 Btu, which is a 4-ton unit.

By having more returns, it helps circulate the air to keep your home at a more even temperature throughout. However, you don&#39;t pull return air from equipment rooms, utility rooms, bathrooms and kitchens.

You can have one filter at the unit to cover all the return air. Having multiple filters is a little overkill, unless they&#39;re piped into the return &#39;after&#39; your main filter?

[nmbexcuse]

Thanks. The individual rooms all have sheet metal ducts that leads to the air handler in the attic, the main return is in the hallway and it has a large duct that leads to the air handler over twenty feet away, I don&#39;t know why it&#39;s done this way but house was built 30 years ago so may be a different standard then?

[<kjpro]

A lot of times you will have returns in the bedrooms, while you have 1 or 2 larger returns in a central area to cover the living/family/dining rooms.

Since your filters are in the ceiling &#39;filter&#39; grills, all of them *are* necessary.

[nmbexcuse]

Thank you for the advise. Now I have a stupid question...

So now I have 4 small returns and a large main return in the hallway, and the cool air is being fed to 4 bed rooms, 3 bathrooms, and a family room.

I would like to install two ceiling fans in two of the bedrooms. Unfortunately both the returns and supply grille are both "near" the center of the room where I want to hang the ceiling fan. They are not right there in the center, but they are near enough. I can&#39;t say why, but is there any reason a return or supply grille should not be inside the sweep radius of a ceiling fan (other than the fact it looks odd to me)?

I asked the AC techs (I still have not determined who to hire yet) if it&#39;s possible to relocate the return and supply from the center of the room to the edge of the room, he said this would require running brand new ducts because these 30 year old sheet metal ducts once he touch them they may just leak and break - and I think he is right...

MC

[<kjpro]

It must be a very small room to be able to cover both of them with a ceiling fan. Otherwise, they should be separated further apart. The supply near an outside wall and the return in a corner near the center part of the house.

It would look odd to have a fan covering both grills.

Sheet metal ducts that fall apart... ? hummmm, so are you saying the metal is rusted and very thin? If not, how is it going to just leak and break? Sounds more like the contractor just doesn&#39;t want the job of relocating the grills.

[nmbexcuse]

The room is not very small, standard size, 12&#39;x13&#39; and the other

15&#39;x12&#39;, but for some reason the return and supply are all near the center in the ceiling. They are both 9"x9" or 10"x10" small squares. I don&#39;t know why they are not on the edge, I guess the idea was if they place it in the middle it will distribute to all sides of the room equally? Now that I am remodeling the rooms, I have to figure out the proper positions of AC return and supply, high hat lights, ceiling fan etc...

No, I removed the grilles and looked up the duct and they look fine, no corrosion whatsoever. I also went up to the attic and I think the ducts are covered with foam on the outside and those foam seemed brittle when touched.

[M Q]

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Get the supply and return vents away from each other! Otherwise, the air just comes out the supply and back into the return without doing much for the room. Best to have them on opposite sides of the room.

[<kjpro]

You want the supply located by the walls that are gaining/losing heat. The return should be towards the inner part of the home. Normally, this is by the doors.

Then why can&#39;t they be moved? The pipes can always be re-insulated.