# Back draft devise

**URL:** <https://forum.nachi.org/t/back-draft-devise/39585>\
**Category:** Inspecting HVAC Systems\
**Created:** [June 16, 2009, 2:29am UTC](https://forum.nachi.org/t/back-draft-devise/39585 "2009-06-16T02:29:24Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![belliott](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/belliott/32/57038_2.png) [@belliott](https://forum.nachi.org/u/belliott)\
**Post date:** [June 16, 2009, 2:29am UTC](https://forum.nachi.org/t/back-draft-devise/39585/1 "2009-06-16T02:29:24Z")

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Wondering if these are ok to use, and what about that flap viewed from bottom opening.?  
Do not see any links on these.

Section can be seen just inside the crawlspace area past the water heater.

![flue (Small).JPG](https://global.discourse-cdn.com/internachi/original/2X/6/673081680e2f920f68737b01502ae7621938eb7b.jpeg) ![flue2 (Small).JPG](https://global.discourse-cdn.com/internachi/original/2X/2/27c6f30a1571fa304125a4a30d58120ac75df60f.jpeg) ![flue 3 (Small).JPG](https://global.discourse-cdn.com/internachi/original/2X/f/fefbfaf39ccdcc6ad17d7adaece2a01a160240bf.jpeg)

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**Author:** ![belliott](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/belliott/32/57038_2.png) [@belliott](https://forum.nachi.org/u/belliott)\
**Post date:** [June 16, 2009, 11:21am UTC](https://forum.nachi.org/t/back-draft-devise/39585/2 "2009-06-16T11:21:31Z")

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Bump

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**Author:** ![rmaday](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/rmaday/32/581_2.png) [@rmaday](https://forum.nachi.org/u/rmaday)\
**Post date:** [June 16, 2009, 3:56pm UTC](https://forum.nachi.org/t/back-draft-devise/39585/3 "2009-06-16T15:56:09Z")

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I have no idea what you’re trying to ask about.

Got a circle or arrow or something? Other wise “these” look fine. 😉

Pic 2 has significant rust, but you knew that already. 🙂

TPRV drain a bit short (looks capped also).

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**Author:** ![belliott](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/belliott/32/57038_2.png) [@belliott](https://forum.nachi.org/u/belliott)\
**Post date:** [June 16, 2009, 5:35pm UTC](https://forum.nachi.org/t/back-draft-devise/39585/4 "2009-06-16T17:35:12Z")

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Just wondering if that hood looks ok.

TPR is last of worries here.  
Thanks Rick, as the rest are to busy worrying about David Letterman to think of HI stuff.

Hmmm… maybe I should go to Inspection news.🙂

Did you notice the column? 🙂

Good catch on the TPR as I told client that the coupling is not allowed either and to replace the whole pipe after heater is moved up on a pad.

Foundation is flooded with 3 sumps 3 additions to house ,bad grading.short down spouts,trees from neighbor.plastic tarp with rocks against wall catching and retaining water …better stop there.

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**Author:** ![Gary\_Reecher](https://avatars.discourse-cdn.com/v4/letter/g/c68b51/32.png) [@Gary\_Reecher](https://forum.nachi.org/u/Gary_Reecher)\
**Post date:** [June 21, 2009, 8:09pm UTC](https://forum.nachi.org/t/back-draft-devise/39585/5 "2009-06-21T20:09:49Z")

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**That box installed in the pipe is a draft hood. There is also a draft hood on top of the water heater. That is double drafting and will cause improper venting of the flue gases.**