Water Heaters - Odd drain tube

Hi all,

At the bottom of the valve on the inlet pipe of my water heater, there is an odd clear tube that is constantly draining water. I followed it, and it leads to a larger drain pipe in the floor. It doesn't appear to serve an purpose except waste water. When I pull the clear pipe from the CPVC pipe it's inserted into, there is a steady stream of water flowing from it.
Anyone have any idea what the purpose of this is, if any?
Thanks!http://i572.photobucket.com/albums/ss164/the1burgh/water_heater.jpg

It would be helpful to to see picture shows the heater and its immediate surroundings.

It's a pressure relief valve that is used in place of a diaphragm expansion tank. Its purpose is to relieve excess pressure caused by thermal expansion (from heating water) and is a lousy way in my opinion. You can remove the relief valve from the shut off valve and insert an 1/8 inch plug IF you also install an expansion tank.

You may also have a malfunctioning pressure regulating valve (PRV) in your water supply piping.

It's a pressure relief valve that is used in place of a diaphragm expansion tank. Its purpose is to relieve excess pressure caused by thermal expansion (from heating water) and is a lousy way in my opinion. You can remove the relief valve from the shut off valve and insert an 1/8 inch plug IF you also install an expansion tank.

You may also have a malfunctioning pressure regulating valve (PRV) in your water supply piping.

Thanks for the replies. I have attached another pic, but don't even see a pressure regulating valve. Can you locate it on the pic?
http://i572.photobucket.com/albums/ss164/the1burgh/water_heater_3.jpg

If that valve right above the water meter is the main shut off then you don't have a PRV.

You need to add a tee in the copper piping that runs between the water heater shut off valve and the temperature regulating valve (the silver one with the hot water from the tank and also the hot water to the home) and then run piping to a diaphragm expansion tank. The piping to the tank can be 1/2 inch size and can be either copper or approved plastic. Mount the expansion tank to prevent any stress on the connecting piping and the tank connection.

For starters:

<link rel="File-List" href="file:///C:%5CDOCUME%7E1%5CADMINI%7E1%5CLOCALS%7E1%5CTemp%5Cmsohtml1%5C05%5Cclip_filelist.xml"><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><style> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} --> </style><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} </style> <![endif]-->2006 IRC P2803.6.1 Requirements for discharge pipe. The discharge piping serving a pressure-relief valve, temperature relief valve or combination valve shall:
1. Not be directly connected to the drainage system.
2. Discharge through an air gap located in the same room as the water heater.
3. Not be smaller than the diameter of the outlet of the valve served and shall discharge full size to the air gap.
4. Serve a single relief device and shall not connect to piping serving any other relief device or equipment.
5. Discharge to the floor, to an indirect waste receptor or to the outdoors. Where discharging to the outdoors
in areas subject to freezing, discharge piping shall be first piped to an indirect waste receptor
through an air gap located in a conditioned area.6. Discharge in a manner that does not cause personal injury or structural damage.
7. Discharge to a termination point that is readily observable by the building occupants.
8. Not be trapped.
9. Be installed to flow by gravity.
10. Not terminate more than 6 inches (152 mm) above
the floor or waste receptor.
11. Not have a threaded connection at the end of the piping.
12. Not have valves or tee fittings.
13. Be constructed of those materials listed in Section P2904.5 or materials tested, rated and approved for
such use in accordance with ASME A112.4.1.

And while I can't tell for sure from the picture, some lines may be too close to the draft hood and/or vent pipe.
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Thanks again for the replies, and excuse my ignorance as I try and understand this setup.

So, Michael...you are saying that the clear tubing that feeds into the CPVC pipe is no longer compliant due to it feeding into the same tube as the Pressure Relief Valve on the tank?

And Furd...does it matter if the T-connector is to the right or left of the vertical copper pipe that feeds in to the tank?
...and what ensures that the expanded water goes into the expansion tank instead of back through the shutoff valve to the right, and into that piping?

Every pressure, temperature or combination TPRV must be full compliant with P2803.6, which means that it needs its own, dedicated,complaint drain line - the line must meet all the requirements in that section of the code.

your t&p valve drain is compliant with that code with the exception of the otherr pipe draining into it but may or may not be the code where you are.

an expansion tank allows the xtra pressure in a closed system to expand into it to protect the system. you have a check valve that stops the water from pushing back into you cold line.

your t&p valve drain is compliant with that code with the exception of the otherr pipe draining into it but may or may not be the code where you are.

an expansion tank allows the xtra pressure in a closed system to expand into it to protect the system. you have a check valve that stops the water from pushing back into you cold line.

Thank you for clarifying this plumbermandan. I'll be installing an expansion tank to meet code and to save on water that is being wasted through the current setup.