Help with age of Carrier A/C unit

This is a Carrier central A/C unit.

Model #50YH036300

S/N # 0869948


Preston’s says between 1981 & 1986.

Thanks Buck, we thought so because of the 086 at the beginning of the S/N, Just was not sure.

Carrier Blue Book concurs.

Thanks Chris, thats what I thought.

That first digit should be the letter O and not the number zero, which would give you February 1986.

Russel, How does o relate to February?

Just curious.

My research indicates that they apparently didn’t like the convention that everyone else was using (A = January, skip “I”), so they did
N = January

Z = December.

Here’s what’s interesting, though. In order to get from N to Z, one has to leave out a letter. Usually one leaves out the letter “O” since it can be confused with the number “0” (the letter usually is fatter than the number, which can help in copying numbers if one compares the letter/number to other letters/numbers on the manufacturing plate). I do have confirmed serial numbers from January (N) through July (T), and the only way to get from N to T is to include O. I also have other confirmed serial numbers with the letter O, in addition to the one here.

My research is incomplete from August to December, so I don’t know which letter they left out. I suspect X since it’s commonly used to mark the spot. :slight_smile:

This is a good link for info on air conditioners,

For A C age info follow the link below.

Thanks Russel & Greg.

This is what makes NACHI great!

PS Whatever happened to keeping it simple?

How about this one. It’s also a Carrier
Model: 38EN024310
S/N: R636373

The furnace is a 1985 DOM and the house was built in 1962. I was trying to follow the letter codes from this post, but I didn’t find and R.


That one is April 1986.