# Steam vent??

**URL:** <https://forum.nachi.org/t/steam-vent/12180>\
**Category:** Inspecting HVAC Systems\
**Created:** [January 25, 2007, 6:55pm UTC](https://forum.nachi.org/t/steam-vent/12180 "2007-01-25T18:55:12Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![brepanshek](https://avatars.discourse-cdn.com/v4/letter/b/9de0a6/32.png) [@brepanshek](https://forum.nachi.org/u/brepanshek)\
**Post date:** [January 25, 2007, 6:55pm UTC](https://forum.nachi.org/t/steam-vent/12180/1 "2007-01-25T18:55:12Z")

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What you are looking at is sometype of vent??? ![DSCF0001 (Small).JPG](https://global.discourse-cdn.com/internachi/original/2X/a/ad5accc738abd31c402bb2504b74b29809d5ec59.jpeg) This is on the return piping to a steam boiler. All the room radiators have no steam release valves on them, just supply pipe in and a return pipe out.

When the boiler fires up on call for heat you can hear a whistling coming from this thing on the return pipe. I’m guessing this is correct to hear, and assume it’s working correctly??? Give me your input.

![DSCF0001 (Small).JPG](https://global.discourse-cdn.com/internachi/original/2X/a/ad5accc738abd31c402bb2504b74b29809d5ec59.jpeg)

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**Author:** ![cbottger](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/cbottger/32/206_2.png) [@cbottger](https://forum.nachi.org/u/cbottger)\
**Post date:** [January 26, 2007, 5:49am UTC](https://forum.nachi.org/t/steam-vent/12180/2 "2007-01-26T05:49:39Z")

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> [@brepanshek](#):
>
> What you are looking at is sometype of vent??? ![DSCF0001 (Small).JPG](https://global.discourse-cdn.com/internachi/original/2X/a/ad5accc738abd31c402bb2504b74b29809d5ec59.jpeg) This is on the return piping to a steam boiler. All the room radiators have no steam release valves on them, just supply pipe in and a return pipe out.
> 
> When the boiler fires up on call for heat you can hear a whistling coming from this thing on the return pipe. I’m guessing this is correct to hear, and assume it’s working correctly??? Give me your input.

What does the condensate return to. A CRU or what.

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**Author:** ![brepanshek](https://avatars.discourse-cdn.com/v4/letter/b/9de0a6/32.png) [@brepanshek](https://forum.nachi.org/u/brepanshek)\
**Post date:** [January 26, 2007, 1:37pm UTC](https://forum.nachi.org/t/steam-vent/12180/3 "2007-01-26T13:37:03Z")

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It returns to a hartford loop then into the boiler.

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**Author:** ![brepanshek](https://avatars.discourse-cdn.com/v4/letter/b/9de0a6/32.png) [@brepanshek](https://forum.nachi.org/u/brepanshek)\
**Post date:** [January 26, 2007, 1:37pm UTC](https://forum.nachi.org/t/steam-vent/12180/4 "2007-01-26T13:37:28Z")

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What is CRU stand for???

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**Author:** ![gbeaumont](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/gbeaumont/32/1094_2.png) [@gbeaumont](https://forum.nachi.org/u/gbeaumont)\
**Post date:** [January 26, 2007, 4:11pm UTC](https://forum.nachi.org/t/steam-vent/12180/5 "2007-01-26T16:11:39Z")

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Hi to all,

Brian, what you are seeing there is a Jacobus Maid O’Mist air valve used to vent air from the supply/return lines.

[http://www.kingsolar.com/catalog/mfg/maidomist/1straight.html](http://www.kingsolar.com/catalog/mfg/maidomist/1straight.html)

Regards

Gerry

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**Author:** ![brepanshek](https://avatars.discourse-cdn.com/v4/letter/b/9de0a6/32.png) [@brepanshek](https://forum.nachi.org/u/brepanshek)\
**Post date:** [January 26, 2007, 4:45pm UTC](https://forum.nachi.org/t/steam-vent/12180/6 "2007-01-26T16:45:27Z")

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Thank you Gerry so much. I always get great reponse on the board. Thanks again