# age help please

**URL:** <https://forum.nachi.org/t/age-help-please/34407>\
**Category:** Inspecting HVAC Systems\
**Created:** [December 13, 2008, 7:16pm UTC](https://forum.nachi.org/t/age-help-please/34407 "2008-12-13T19:16:45Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![smcintire](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/smcintire/32/1147_2.png) [@smcintire](https://forum.nachi.org/u/smcintire)\
**Post date:** [December 13, 2008, 7:16pm UTC](https://forum.nachi.org/t/age-help-please/34407/1 "2008-12-13T19:16:45Z")

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Armstrong oil fired furnace  
Model # L78B4DC12-1  
SER# A 26682BNA

Thanks!

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**Author:** ![rharrington](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/rharrington/32/1467_2.png) [@rharrington](https://forum.nachi.org/u/rharrington)\
**Post date:** [December 13, 2008, 10:04pm UTC](https://forum.nachi.org/t/age-help-please/34407/2 "2008-12-13T22:04:50Z")

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Steve are you sure this is the complete model number?

Model # L78B4DC12-1

Preston guide has a model number L78B84DC12 in 1992 through 1995.

Hope this helps.

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<div class="post-metadata">

**Author:** ![smcintire](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/smcintire/32/1147_2.png) [@smcintire](https://forum.nachi.org/u/smcintire)\
**Post date:** [December 13, 2008, 10:18pm UTC](https://forum.nachi.org/t/age-help-please/34407/3 "2008-12-13T22:18:02Z")

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Yes, that helps. I guess it would help to put all tne numbers in L78B84DC12-1  
Thanks,  
Steve McIntire

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**Author:** ![rray](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/rray/32/2162_2.png) [@rray](https://forum.nachi.org/u/rray)\
**Post date:** [December 14, 2008, 10:28am UTC](https://forum.nachi.org/t/age-help-please/34407/4 "2008-12-14T10:28:18Z")

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The last three letters of the serial number give you the date of manufacture:

B = month  
N = year  
A = place of manufacture

B = February  
N = 1992

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<div class="post-metadata">

**Author:** ![smcintire](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/smcintire/32/1147_2.png) [@smcintire](https://forum.nachi.org/u/smcintire)\
**Post date:** [December 14, 2008, 5:21pm UTC](https://forum.nachi.org/t/age-help-please/34407/5 "2008-12-14T17:21:57Z")

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Thanks for the help