I HAVE A FEDDERS MODELA3X05FEA SERIAL JNO13839246A HOW MANY BTU IS IT

Try Fedders web site

How do I tell the age of a Fedders furnace or air conditioner from the serial number?
Although the Fedders brand is used for window units nowadays, this encoding only applies to when they manufactured unitary (split) systems years ago. The second letter of the serial number indicates the year of manufacture (from 1966 to 1977):
A = 1966 B = 1967 C = 1968
D = 1969 E = 1970 F = 1971
G = 1972 H = 1973 I = (not used)
J = 1974 K = 1975 L = 1976 M = 1977
An ancient Fedders unit we recently inspected had the serial number AH11877, indicating that it was manufactured in 1973. The home was built in 1973, which provided a secondary verification of the manufacture date indicated by the serial number

https://www.manualslib.com/brand/fedders/air-conditioner.html

Looks to be a 12,000 btu

Usually the front is held on with screws on the sides of the unit. I would check behind the filter screen trim plate as well. I would be surprised if the front is just snap locked on.

Fedders A6Y12F2A-A - 12,000 BTU

First, I'm not a Fedders tech.
* Repairs must be done by a Certified Refrigeration Tech.
* Check your warranty and call for service.
*** The following is for information only ***
Info link and service manual;
https://www.google.com/search?client=firefox-b-1&ei=n-Q7W9ybIqac0gKF97DYDw&q=Fedders+Air+Conditionner+pdf&oq=Fedders+Air+Conditionner+pdf&gs_l=psy-ab.12...3704.7371.0.8654.4.4.0.0.0.0.155.607.0j4.4.0....0...1c.1.64.psy-ab..0.3.456...0i13k1j33i160k1.0.tva6VApcC8U
* Be safe, call for service
Aloha, ukeboy57

It is an 8000 BTU, I have one myself. The model A6Q08F2A

The Fedders A6Q10F2A, is a 10,000 BTU

Hi, The numbers you have given tell me, this unit is a 8,000 btu unit.!2, 000 btu's equal a ton of cooling, so you are just under a ton. This is about all I can tell you. There should be a data plate that will give you amps, volts, compressor amps ect.
Shastalaker7
A/C, Contractor

BTU means "British thermal units" and is a measurment of cooling and heating capacity. Other units are Kw "Kilowatts", and HP "Horse Power".
To convert
Multiply by
To obtain
kW
1.341
hp

kW
3,413
Btu/hr
hp
2,545
Btu/hr