Heating Unit + Return?

[Allsbury]

How do I determine the size of my heating unit? The only info I can find on the unit is that it is an Confortmaker RPJ II. It has a 2000CFM FAST media filter at the inlet plenum.

Once I know the size whats the rule of thumb for return air ducts?

I have two 30" x 12" registers on first floor of my 1925 bumglaow. One in the living room and one adjacent a large dining room. The rooms are connected by a six foot passageway and the returns are ~20ft apart. I also have 1 register on 2nd floor and one in the basement. I want to loose one of the registers on the first floor.

Any thoughts? Thanks in advance for reponse.

[hvac4u]

what is the model # from the tag inside the unit? do you have a/c? what is that model#?

[Ed Imeduc]

Is that 2000CFM just on the filter or on the furnace. thats a lot of air for sure.

ED ;)

[Allsbury]

Heater model # GNE125J20A1 (125,000 BTU /hr)
A/C model # AG048GB2

The 2000 CFM info is on the case that holds the air filter. The air filter is ~5" thick. The air filter is located between the furnace and the 'cold' air plenum.

Any help on this would be greatly appreciated.

Chad