How To Plumb A Water Heater With Pex

PEX at Water Heaters & TPR valves
Pipage connection requirements, restrictions, codes

• Mail a QUESTION or COMMENT about this PEX piping at water heating equipment & TPR valves

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This article describes the requirements for copper or other metallic piping to protect PEX piping from heat damage at a water heater.

Nosotros also discuss the use of PEX tubing for heating equipment discharge tube pipage

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Proper vs Wrong PEX Plumbing Connections to a H2o Heater

PEX Clearance Distances at Water Heaters

• Electric h2o heaters: Zurn PEX tin can be connected directly to residential electric water heaters used for domestic hot h2o (Zurn PEX uses brass adapters for this connection)
• Gas water heaters: vi" or more than from exhaust flue
• Gas water heaters, power vented: 6" or more from metal blower housing except if blower housing itself is plastic (then direct-connectedness is permitted)
• QuickPort Manifold (Zurn): xviii" or more from water heater outlet
• Tankless water heaters: 12" or more from frazzle pipe (because this piping an reach 460° F.)
• TPR Discharge tube: PEX is permitted just bank check with the TPR valve and heater manufacturer to be sure that the diameter restriction from PEX fittings is acceptable

- source: (Zurn 2010) cited below

Reader question:

Something I didn't mention, but which shows on the picture of the water heater which I sent earlier and illustrated at Water HEATER SAFETY, are the two hot and cold PEX lines leading directly to the top of the tank.

If the T&P valve is still functional, I understand information technology won't open earlier information technology gets hotter or up to a higher pressure level than is good for PEX .

Then with this configuration is a failure at the tiptop of the tank before the water tin can vent through its proper channel (the T&P valve) unheard of? - Bearding past individual email 2021/07/01

Moderator reply:

PEX water piping should not be connected directly to a gas or oil fired or tankless water heater; in two photos we can run across cerise or blue PEX piping to the top of the water heater.

Merely your h2o heater is electric. Co-ordinate to Zurn (cited beneath) this is a permitted connection if the installation uses Zurn PEX and Zurn PEX fittings.

Really? Other codes and PEX guidelines practise non explicitly permit this connection and are more full general, requiring at least 18" of copper isolating PEX from the water heater - meet our citation below.

For gas or oil fired heaters there are boosted clearance distances required between PEX plumbing and the flue vent connector because that too is an area where high temperatures might exist found.

There are other similar lawmaking citations discussing how PEX tin be connected to all types of water heaters: tank type, instantaneous, and tankless coils, only this one from the Uniform Plumbing Code can suffice:

604.11.2 Water Heater Connections. PEX shall not be installed within the first xviii inches (457 mm) of piping connected to a h2o heater.

cited in

• HUD, PPFA, Blueprint GUIDE for RESIDENTIAL PEX H2o SUPPLY PLUMBING SYSTEMS [PDF] (2006) HUD, U.S. Section of Housing & Urban Evolution, Plastics Pipe Constitute, Inc (PPI) 105 Decker Court Suite 825 Irving, TX 75062 www.plasticpipe.org and Plastic Piping and Fittings Association (PPFA) 800 Roosevelt Road, Bldg. C, Ste. 312 Glen Ellyn, IL 60137 world wide web.ppfahome.org and Partnership for Advancing Engineering science in Housing 451 7th Street, SW Washington, DC 20410 www.pathnet.org and NAHB Inquiry Center, Inc. 400 Prince George's Boulevard Upper Marlboro, MD 20774 www.nahbrc.org retrieved 2019/09/xx or\iginal source: https://www.huduser.gov/portal/publications/pex_design_guide.pdf

You volition detect this same item cited in other PEX plumbing manuals and codes and you lot'll detect it mentioned in quite a few water heater installation manuals.

Lookout out: This is simply 1 more than of multiple prophylactic questions most this particular heater that suggest that its installation appears not to have been inspected / approved by a building official, or if it was, that official didn't practice her job properly.

The risk is a plumbing leak; in the worst example, a outburst hot water pipe could scald someone nearby.

But the risk of burst pipage is partially mitigated, as you lot can read in the following excerpt from the aforementioned HUD document.

In the result of a water heating system malfunction, PEX pipage is designed to adjust short-term conditions of 48 hours at 210ºF (99ºC) and 150 psi (1034 kPa) until repairs can be made. The well-nigh commonly used safety relief valve (T&P) activates (opens) at either of these temperature or force per unit area conditions.

All PEX pipage has been tested to withstand T&P activation for 30 days to ensure that safety requirements are met.

As such, PEX systems DO NOT require the employ of a special T&P valve.

Wade,

I suspect the flexible copper connectors shown in your photo are UL listed or otherwise listed for connecting the appliance or for connecting two of them. However your installation makes me nervous about an increased risk of a catastrophic plumbing leak.

I meet

- flexible plastic water pipes continued to flexible copper connector at the water heater (which is proper) but without any visible back up. Allowing pipes to jerk about invites damage and leaks.

- no shut-off valve on the cold water in to the water heater

- what looks similar a gas fired water heater flue vent connector that is touching or very close to flammable woods framing

- maybe the same vent connector passing through what looks similar foil faced cream (flammable) insulation nether the roof. Give me a photo of the labeling on the insulation and I tin research clearance requirements further.

Dual h2o heaters that are piped in a series with Brasscraft 3/four FIP iron pipe x connected to PEX tubing.

Can i use the same cloth (3/4 Fip)to piping the same h2o heaters in parallel? Or exercise I need to sorer [sic] bodily copper piping?

Thanks

Codes, Standards, Instructions for PEX Pipe Connections at Water Heaters

• PEX Pipe Information.
• Plastic Pipage & Fittings Assoc. PEX INSTALLATION HANDBOOK [PDF] (2016) Plastic Pipe & Fittings Assoc. , Plastic Pipage and Fittings Clan 800 Roosevelt Road Edifice C, Suite 312 Glen Ellyn, IL 60137 world wide web.ppfahome.org

  Cross-linked Polyethylene (PEX) Hot- and Cold-Water Distribution systems And Service Lines
  Excerpts:

  Practice not utilize in applications where the temperature of the water could exceed 180 °F at 100 psi unless specifically approved in the lawmaking, e.1000., h2o heater relief line. See manufacturer'southward recommendations for college operating temperatures at lower pressures.

  Exercise non install PEX tubing downstream of any instantaneous, indicate-of-use or immersed coil water heater where the output is uncontrolled or temperature can exceed 180 °F. Contact manufacturer for recommended metal transition fittings.

  PEX tubing may be connected directly to residential electric tank or tankless (instantaneous) water heaters, if the local code and manufacturer's instructions allow. When connecting PEX tube to gas tank or tankless h2o heaters, the tube must be kept at least vi inches away from the frazzle vent of the heater. Flexible metal water heater connectors may be needed in some instances.

• RELIANCE 40 Gallon Brusque Free energy Efficient Liquid Propane Water Heater MODEL half dozen 40 LBFS- vi Year Warranty

  Excerpt: For homes with plastic pipe, use threaded connectors suitable for the specific type of plastic piping used: CPVC or PEX (cross-linked polyethylene). Do not use PVC pipage.

• Zurn, ZURN PEX PLUMBING INSTALLATION GUIDE [PDF] (2010), ZURN PEX®, Inc. Highway xi Eastward, Commerce, TX, UsaA. 75428 USA, Tel: 1-800-872-7277 Spider web: www.zurn.com

  Canada: ZURN Industries Ltd., 3544 Nashua Bulldoze, Mississauga, Ontario, Canada L4V 1L2 Tel: 905-405-8272 retrieved 2021/07/01 original source: https://api.ferguson.com/dar-stride-service/Query?ASSET_ID=927224&USE_TYPE=INSTALLATION&PRODUCT_ID=3784258
  Excerpts:

  ASTM F 877 is the standard that specifies the performance requirements for a PEX system, tube and fittings together. It has requirements for Minimum Flare-up at 73°F and 180°F, Sustained Pressure level Exam (thousand hours) at 73°F and 180°F, Thermocycling at 100 psi and Excessive Temperature and Pressure level for 30 days to simulate a water heater malfunction. The Zurn PEX systems meet the requirements of ASTM F 877.

  ASTM F 1807 is the standard for brass or copper insert and crimp fittings. This standard specifies acceptable materials for these plumbing equipment and specifies the dimensions for the insert or barbed portion of the fittings. It also gives the dimensions and the material specifications for the copper crimp rings and the finished crimp dimensions. These fittings, when tested with PEX tube accept to come across the performance requirements for PEX systems as required in ASTM F 877. Zurn PEX contumely insert fittings and copper crimp rings meet the requirements of ASTM F 1807.

  ASTM F 2159 is the standard for plastic insert and crimp fittings. This standard specifies the adequate materials and dimensions for the fittings. It likewise has some test requirements for evaluating the quality of the molding process that was used to make the fittings. These fittings, when tested with PEX tube have to encounter the performance requirements for PEX systems as required in ASTM F 877. Zurn PEX plastic insert fittings encounter the requirements of ASTM F 2159.

  Other ASTM Plumbing equipment Standards

  ASTM F 1960 is the standard for "Common cold Expansion Fittings" every bit sold past Wirsbo/Uponor. Zurn PEX tube can be used with these fittings and then the standard number is included in the print cord on our tube but the system is non covered by the Zurn PEX warranty.

  ASTM F 2080 is the standard for "Common cold Expansion Fittings with Metallic Compression Sleeves" as sold by Rehau. Zurn PEX tube tin can be used with these fittings then the standard number is included in the print string on our tube just the system is not covered by the Zurn PEX warranty.

  ASTM F 2098 is the standard for a "Stainless Steel Clamp" to be used in identify of a copper crimp ring for brass or copper insert fittings meeting the requirements of F 1807 or plastic insert fittings meeting the requirements of ASTM F 2159. Zurn PEX does sell rings meeting the requirements of this standard and they are covered by a special, limited time warranty.

  Detailed Description of the Test Requirements of ASTM F 877 for PEX Plumbing Systems

  Burst Test at Room Temperature and 180°F In this test, sample assemblies are subjected to a constantly increasing force per unit area until something fails. The minimum acceptable pressure depends on the size of the tube, only it is a minimum of 620 psi at room temperature and 275 psi at 180°F. The pressure is increased at a rate that will cause failure in nigh 1 minute.

  The significance of this exam is that it demonstrates that the short term forcefulness of the connection exceeds the force of the tube

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How To Plumb A Water Heater With Pex,

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