# High Efficiency FHA system Rust Issue

**URL:** <https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749>\
**Category:** Inspecting HVAC Systems\
**Created:** [May 16, 2022, 3:28pm UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749 "2022-05-16T15:28:36Z")\
**Posts on this page:** 14\
**Page:** 1

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**Author:** ![pbennett1](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/pbennett1/32/59556_2.png) [@pbennett1](https://forum.nachi.org/u/pbennett1)\
**Post date:** [May 16, 2022, 3:28pm UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/1 "2022-05-16T15:28:36Z")

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The attached photo shows significant rust on  
the system’s components. I saw this on three systems last year, and then again last week.  
One unit actually had condensation dripping similar to photo. The intake is connected to the exterior.  
Has anyone determined the cause, and the proper repair?

 ![068 heat](https://global.discourse-cdn.com/internachi/original/4X/f/1/e/f1e036046cacf98bd75bd60e1395f1036adb6812.jpeg)

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**Author:** ![jjonas](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jjonas/32/301755_2.png) [@jjonas](https://forum.nachi.org/u/jjonas)\
**Post date:** [May 16, 2022, 3:57pm UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/2 "2022-05-16T15:57:21Z")

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> [@pbennett1](#):
>
> The intake is connected to the exterior.

Was it installed according to manufacturers specifications?  
Google the install manual, and verify the intake AND exhaust.

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**Author:** ![lkage](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/lkage/32/347658_2.png) [@lkage](https://forum.nachi.org/u/lkage)\
**Post date:** [May 16, 2022, 6:00pm UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/3 "2022-05-16T18:00:57Z")

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> [@pbennett1](#):
>
> The attached photo shows significant rust on  
> the system’s components.

> [@pbennett1](#):
>
> Has anyone determined the cause, and the proper repair?

🤷‍♂️

Report what you see and refer it out to a qualified HVAC tech for correction is what I would do, Peter.

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**Author:** ![rsmith58](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/rsmith58/32/59628_2.png) [@rsmith58](https://forum.nachi.org/u/rsmith58)\
**Post date:** [May 16, 2022, 7:04pm UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/4 "2022-05-16T19:04:58Z")

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Bingo! Report and move on - I tell my clients my job is to report the defects and deficiencies I observe; it is a contractor/expert’s job to determine root cause and make the repair(s).

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**Author:** ![sbridges2](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/sbridges2/32/213319_2.png) [@sbridges2](https://forum.nachi.org/u/sbridges2)\
**Post date:** [May 16, 2022, 9:22pm UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/5 "2022-05-16T21:22:47Z")

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Interesting, My guess would be condensation from cold gas in the line?

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**Author:** ![pbennett1](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/pbennett1/32/59556_2.png) [@pbennett1](https://forum.nachi.org/u/pbennett1)\
**Post date:** [May 18, 2022, 3:04pm UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/6 "2022-05-18T15:04:34Z")

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> [@pbennett1](#):
>
> Has anyone determined the cause, and the proper repair?

Thanks for the replies, BUT, I already know what to write on the report, which is why I asked the question: “Has anyone determined the cause, and the proper repair?” so let me ask again. "Has anyone **determined** the cause, and the **proper** repair? Expert HVAC specialist comments preferred and welcomed!

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**Author:** ![yzou](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/yzou/32/270650_2.png) [@yzou](https://forum.nachi.org/u/yzou)\
**Post date:** [December 10, 2022, 3:46am UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/7 "2022-12-10T03:46:40Z")

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i think so too 😅

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**Author:** ![pbennett1](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/pbennett1/32/59556_2.png) [@pbennett1](https://forum.nachi.org/u/pbennett1)\
**Post date:** [January 8, 2023, 2:28am UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/8 "2023-01-08T02:28:16Z")

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I guess no one knows the answer here, yet.

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**Author:** ![bcawhern1](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/bcawhern1/32/408713_2.png) [@bcawhern1](https://forum.nachi.org/u/bcawhern1)\
**Post date:** [January 8, 2023, 2:38am UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/9 "2023-01-08T02:38:27Z")

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Nope, still guessing. But, I see rust above the pipe. Is it the evaporator coil? Leaking condensation down into the cabinet?

![image](https://global.discourse-cdn.com/internachi/original/4X/8/c/2/8c2a3cef538784c301aa98b984e689e88a094a72.jpeg)

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**Author:** ![ruecker](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/ruecker/32/357170_2.png) [@ruecker](https://forum.nachi.org/u/ruecker)\
**Post date:** [January 8, 2023, 2:45am UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/10 "2023-01-08T02:45:03Z")

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Is there an A coil above? Have any more pics? Further back so we can see the whole unit?

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**Author:** ![rkenney](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/rkenney/32/405447_2.png) [@rkenney](https://forum.nachi.org/u/rkenney)\
**Post date:** [January 8, 2023, 2:46am UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/11 "2023-01-08T02:46:36Z")

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> [@pbennett1](#):
>
> I guess no one knows the answer here, yet.

Are you a Home Inspector or an HVAC tech? Just report what you see. Do you have a condensation leak? That should be reported. Guesses should not. Your pictures don’t tell me that the surface rust is a concern. Off the top of my head I would say the wrong fittings were used.

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**Author:** ![bcawhern1](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/bcawhern1/32/408713_2.png) [@bcawhern1](https://forum.nachi.org/u/bcawhern1)\
**Post date:** [January 8, 2023, 2:51am UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/12 "2023-01-08T02:51:33Z")

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I would bet $100 on it coming from above. I see more clues. Drip stains and rust.

![image](https://global.discourse-cdn.com/internachi/original/4X/d/d/1/dd159eecccc81a068fd76dbfec448547a92b6abe.jpeg)

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**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:** [January 8, 2023, 1:52pm UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/13 "2023-01-08T13:52:56Z")

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I do, but I need a lot more information, yet provided…

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**Author:** ![amarshall7](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/amarshall7/32/301000_2.png) [@amarshall7](https://forum.nachi.org/u/amarshall7)\
**Post date:** [March 9, 2023, 8:53pm UTC](https://forum.nachi.org/t/high-efficiency-fha-system-rust-issue/215749/14 "2023-03-09T20:53:51Z")

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I am a HVAC Tech for over 20 years and a HVAC City Inspector. My guess from looking at pictures is this: My best guess is the combustion air intake is right above that rust piped in with PVC from the outside. Cold air + hot flame/metal is condensing water vapor. Guessing that because it is centered right on burner box where the intake should be. Someone asked about mixing the exhaust, the exhaust is always connected to the inducer vent motor assembly. The main worry as a tech is that gas valve gets too much moisture on it and breaks it. Again unless you are a HVAC tech and know for 100% fact of issue I would describe your observation on report and recommend evaluation by a HVAC professional. Not likely a safety issue but could cause a no heat issue in the future.
