hvac age

can someone tell me how to find out how old this system is? php12a24da-1a s/n 8497c13035 made by armstrong

Richard, try here:
http://www.armstrongair.com/contact.php

They are a Lennox internation company which are ISO certified, they should be able to look it up for you

Thank you

My guess, without looking at the unit, is march of 1997

Anatol