# Rust/Moisture at burner ports. **URL:** \ **Category:** Inspecting HVAC Systems\ **Created:** [February 23, 2007, 11:08pm UTC](https://forum.nachi.org/t/rust-moisture-at-burner-ports/13448 "2007-02-23T23:08:08Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![dmacy](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dmacy/32/1466_2.png) [@dmacy](https://forum.nachi.org/u/dmacy)\ **Post date:** [February 23, 2007, 11:08pm UTC](https://forum.nachi.org/t/rust-moisture-at-burner-ports/13448/1 "2007-02-23T23:08:08Z")
What would cause the Rust/moisture at the burner ports. The unit is a Armstrong manufactured in 2001. It appeared to be venting properly and the A coil is below the burners. Thanks ![91907 021 (Small).jpg](https://global.discourse-cdn.com/internachi/original/3X/0/6/06ca7c6259f5ebd547298a658a916a08c7bf1723.jpeg) ---
**Author:** ![dmacy](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dmacy/32/1466_2.png) [@dmacy](https://forum.nachi.org/u/dmacy)\ **Post date:** [February 23, 2007, 11:52pm UTC](https://forum.nachi.org/t/rust-moisture-at-burner-ports/13448/2 "2007-02-23T23:52:53Z")
Bump ---
**Author:** ![tdietrich1](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/tdietrich1/32/1561_2.png) [@tdietrich1](https://forum.nachi.org/u/tdietrich1)\ **Post date:** [February 23, 2007, 11:54pm UTC](https://forum.nachi.org/t/rust-moisture-at-burner-ports/13448/3 "2007-02-23T23:54:30Z")
IMHO, Looks like some condensation. I would comment about it, and recommend like all gas fired appliances, it should be inspected and service regularly by a professional. tom ---
**Author:** ![Paul\_Tos](https://avatars.discourse-cdn.com/v4/letter/p/bc79bd/32.png) [@Paul\_Tos](https://forum.nachi.org/u/Paul_Tos)\ **Post date:** [February 24, 2007, 1:13am UTC](https://forum.nachi.org/t/rust-moisture-at-burner-ports/13448/4 "2007-02-24T01:13:13Z")
Would write it up as previous poster stated. For reference: Possible cause for this would be a switch over from a gravity type exhaust system (less then 70% efficient usually a 5 in pipe) being converted to an induced motor exhaust (80% efficient usually a 4 in pipe), and then venting through a standard brick chimney (inside or exterior - condition from picture makes me believe an exterior in this case) w/o installing required flue liner. Believe what happens, is that in the gravity type exhaust, standard chimney is allowed to heat properly, as the air is heated, it rises. Thru the new 80% induced motor exhaust, the heated air never propertly warms the chimney due to inducement, thus causing excessive condensation. ---
**Author:** ![bkelly2](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/bkelly2/32/58257_2.png) [@bkelly2](https://forum.nachi.org/u/bkelly2)\ **Post date:** [February 24, 2007, 1:35am UTC](https://forum.nachi.org/t/rust-moisture-at-burner-ports/13448/5 "2007-02-24T01:35:02Z")
Incomplete combustion [http://www.nationalfurnace.com/advice.htm](http://www.nationalfurnace.com/advice.htm) [http://www.lennox.com/pdfs/manuals/Lennox%20G61%20Manual.pdf](http://www.lennox.com/pdfs/manuals/Lennox%20G61%20Manual.pdf) Reccomend CO detector be installed in every house with fuel appliances and or fireplaces. ---
**Author:** ![Paul\_Tos](https://avatars.discourse-cdn.com/v4/letter/p/bc79bd/32.png) [@Paul\_Tos](https://forum.nachi.org/u/Paul_Tos)\ **Post date:** [February 24, 2007, 1:51am UTC](https://forum.nachi.org/t/rust-moisture-at-burner-ports/13448/6 "2007-02-24T01:51:54Z")
A good pdf 1.+ mb file which hits on combusiton air venting sizing and theory [http://www.duravent.com/tech.htm#tech](http://www.duravent.com/tech.htm#tech) then click on sizing handbook picture 2/3 down on page right side to download ---
**Author:** ![dandersen](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dandersen/32/59398_2.png) [@dandersen](https://forum.nachi.org/u/dandersen)\ **Post date:** [February 26, 2007, 2:42am UTC](https://forum.nachi.org/t/rust-moisture-at-burner-ports/13448/7 "2007-02-26T02:42:33Z")
Low heat exchanger temp from a/c, condensing ambient air moisture. ---
**Author:** ![jkormos](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jkormos/32/1701_2.png) [@jkormos](https://forum.nachi.org/u/jkormos)\ **Post date:** [February 26, 2007, 6:53pm UTC](https://forum.nachi.org/t/rust-moisture-at-burner-ports/13448/8 "2007-02-26T18:53:36Z")
> [@tdietrich1](#): > > IMHO, > > Looks like some condensation. I would comment about it, and recommend like all gas fired appliances, it should be inspected and service regularly by a professional. > > tom I would have to agree, with tearing into the unit, which is not our job anyway