Building Code and Building Construction - Questions and Answers
Or when you want to know how construction is supposed to be done.

|
AskCodeMan.com
|

Custom Search

Pex supply and discharge

Pex supply and discharge

New postby wwilson3 on Mon Aug 10, 2009 10:32 am

Hi there
Can pex be connected directly to the tank with out 18 inches of solid pipping ( electric or gas)
wwilson3
 
Posts: 4
Joined: Mon Aug 10, 2009 10:12 am
Location: Powell TN

Re: Pex supply and discharge

New postby Jerry Peck - Codeman on Mon Aug 10, 2009 1:33 pm

wwilson3 wrote:Can pex be connected directly to the tank with out 18 inches of solid pipping ( electric or gas)


Electric: Yes but ... the following items must also be followed.

Gas: No but ... in addition to the following items, such as regarding the clearance from Type B Gas Vents being shown as only 1 inch, keep in mind that the clearance from the draft hood is 6 inches just like the clearance from single wall vents is and the PEX must be kept a minimum of 6 inches away from the draft hood as measured from the lip and sloping surface of the draft hood.

Also keep in mind that in garages the garages are filled with direct sunlight when the garage doors are open or when there are windows which allow sunlight into the garage, and that PEX is not to be exposed to direct sunlight.

Also keep in mind that attics with off-ridge vents, wind turbines, and some other types of vents light direct sunlight into the attic and the PEX is not allowed in direct sunlight.

Keep in mind that PEX connected to water heaters in garages may be susceptible to "organic chemicals, pesticides, strong acids or strong bases to come into contact with Uponor PEX" from items stored on the water heater.

When reading the following list keep an open mind as to what each item applies to, some of which I addressed above.

From the Uponor PEX installation guides:
- Handling Guidelines for PEX Tubing
- - Although not comprehensive, the following highlights the most common guidelines to use when handling Uponor PEX tubing:
- - - Install Uponor systems according to the manufacturer's installation instructions. Failure to follow the instructions and installation guidelines can result in the failure of Uponor systems.
- - - Do not use Uponor PEX where temperatures and pressures exceed ratings.
- - - Do not use or store Uponor PEX where it will be exposed to direct sunlight for more than 30 days.
- - - Do not weld, glue or use adhesives or adhesive tape with Uponor PEX.1
- - - Do not apply open flame to Uponor PEX.
- - - Do not install Uponor PEX within 6 inches of any gas appliance vents, with the exception of double-wall B-vents, which have a minimum clearance of 1 inch.
- - - Do not install Uponor PEX within 12 inches of any recessed light fixtures, unless the PEX line is protected with suitable insulation.
- - - Do not solder within 18 inches of any Uponor PEX tubing in the same water line. Make all sweat connections prior to making the fitting connection.
- - - Do not use Uponor PEX to convey natural gas.
- - - Do not install Uponor PEX between the tub/shower valve and tub spout.
- - - Do not use Uponor PEX for an electrical ground.
- - - Do not spray on or allow organic chemicals, pesticides, strong acids or strong bases to come into contact with Uponor PEX.
- - - Do not use petroleum or solvent-based paints on Uponor PEX.
- - - Use only approved and appropriate firestop materials with Uponor PEX.
- - - Do not allow rodents, insects or other pests to come into contact with Uponor PEX tubing.
- - - Do not subject Uponor PEX to impact.
- - - During remodeling or ceiling repair, implement appropriate precautions to protect the tubing from damage.
- - - Uponor PEX and fittings are intended for use in systems outlined on page 1.

Viega PEX (formerly Vanguard PEX) installation manual states:
- 10.10 Water Heaters
- - PureFlow tubing should not be connected directly to gas-fired water heaters. The high temperatures of these appliances can damage the tubing. When connecting a PureFlow system to a gas-fired water heater, install a minimum of 18" of metallic piping between the water heater and tubing, keeping tubing more than 6" away from the vent pipe. Where local code allows, PureFlow tubing may be connected directly to electric water heaters and used for hot water recirculation lines which do not come within 6" of the gas heater vent.
- - ViegaPEX may be used to connect to instantaneous / tankless water heaters or other hot water producing devices. However, consult manufacturer’s recommendations for use with plastic tubing and ensure temperature and pressure do not exceed the maximum ratings of the tubing.
- 10.11 Heaters, Flues, Vents and Recessed Lights
- - Keep PureFlow PEX tubing a MINIMUM of 12" vertically and 6" horizontally from sources of high heat such as gas flue vents, heating appliances or electric motors. (then this continues on about recessed lights, etc.)

Uponor's installation guide is not a clear and concise, in some ways, not a complete as, Viega PEX, thus applying the Viega PEX requirements should provide a good standard to use.
Jerry Peck - CodeMan
AskCodeMan.com
Construction Litigation Consultant - Retired
Construction and Code Consultant - Semi Retired
User avatar
Jerry Peck - Codeman
Site Admin
 
Posts: 1199
Joined: Fri Dec 12, 2008 12:06 pm

Re: Pex supply and discharge

New postby wwilson3 on Tue Aug 11, 2009 12:35 pm

Thanks Jerry
I just wanted a second thought on this been a dispute around here. I new gas but was not sure about electric. How ever the sun light thing is good to know.
wwilson3
 
Posts: 4
Joined: Mon Aug 10, 2009 10:12 am
Location: Powell TN

Re: PEX supply and discharge

New postby Jerry Peck - Codeman on Tue Aug 11, 2009 4:08 pm

Yes, just gas as the newer electric water heaters (of the last 20-30 years, and especially the newer foam insulated ones since around 1990) are insulated enough to keep the heat in the water that there is not much heat being transmitted to the surrounding area.

Gas water heaters are also well insulated but the draft hood and the vent, either Type B Gas Vent or single wail, are the problem areas.

The powered vent water heaters with the PVC for the vents would also not be a problem as there is not much heat transmitted through the PVC vents.
Jerry Peck - CodeMan
AskCodeMan.com
Construction Litigation Consultant - Retired
Construction and Code Consultant - Semi Retired
User avatar
Jerry Peck - Codeman
Site Admin
 
Posts: 1199
Joined: Fri Dec 12, 2008 12:06 pm


Return to Plumbing: Water heaters, fixtures, traps, hose bibbs, water pressure, supply & DWV piping



Who is online

Users browsing this forum: No registered users and 7 guests