hot/cold water fittings on Atwood Water Heater

[Jenny]

Hi ladies and gents-
Can anyone tell me what type of fittings to use on the hot and cold intake/outlet on an Atwood water heater?  I've called Atwood twice and they will not commit to an answer.  Their instructions say to use a high-quality plastic; the person on the phone said make sure it's rated for at least 140 degrees but would not recommend any manufacturer or source.  This is brand new, out of the box and I'm putting it in a homemade rig.

Thanks for your help!
Jenny

 

[Mikeh449]

pec fittings from lowes or home depot or any hardware store take old ones with you

 

[Ned]

Those would be Pex (not pec).

 

[Jenny]

I don't have any old ones because this is a build from scratch RV and I'm putting it in new. 
Thanks-
J

 

[John From Detroit]

If it is a threaded fitting on the water heater it is 1/2 inch Iron Pipe (standard water pipe thread) most likely,, Take a measurement, I would use plastic (high temp rated) fittings though.  Make sure they are rated for water heater use.

 

[Rene T]

I would use  brass fittings and not black iron. Black iron will rust over time. Also, keep in mind when it comes to winterizing. If it's a one valve bypass system, you'll need to install a check valve  (available at most RV place's) in the outlet hole which will be the top hole. This is so you don't fill your hot water tank needlessly with pink antifreeze. If you're going to use a 3 valve bypass system, just use a couple of 2" close nipples available at Home depot, Lowe's or any hardware store.

 

[Gary RV_Wizard]

I'm not sure what you were expecting from Atwood, since you are talking about the plumbing system YOU are designing for your homemade RV. You need sufficient knowledge of hot and cold water plumbing to do that.  RV manufacturers typically use PEX (XLPE) tubing and compatible fittings, but you have to select a variety of PEX that has the pressure and temperature ratings needed to meet residential plumbing standards. PVC and CPVC are alternatives, but PVC isn't as robust for the rigors of over-the-road travel. You can probably get advice at a Lowes or Home Depot, or any plumbing supply shop.

You should probably design the water heater plumbing with a heater bypass system, to simplify winterizing your new RV. You can design your own or buy a prepackaged set of valves from an RV supply house.

 

[Bill B]

PEX and NO iron, brass, etc on the tank itself. The tank is Aluminum and any of the metals will set up a galvanic reaction. John really should have said 1/2 standard pipe thread and left out the iron.

Manual - http://www.atwoodmobile.com/manuals/waterheaters/MPD%2093756%20SP%2011.19.07.pdf

DO NOT USE EVER, an anode rod in an ATWOOD.

 

[John From Detroit]

Bill, I have always said the thread size listed as 1/2 Inch IPT
IPT stands for Iron Pipe Thread.

Thats why I phrased it that way.... I also added use plastic fittings, (The reason for plastic. You explained).

 

[tvman44]

My Atwood water heater has a 1/2" gray plastic fitting on the tank and the PEX connects to that.

 

[Gary RV_Wizard]

Bill, I have always said the thread size listed as 1/2 Inch IPT
IPT stands for Iron Pipe Thread.

The standard acronym for pipe thread is NPT, not IPT.  NPT=National Pipe Tapered Thread and refers to the ANSI and ASME national standards of that name.

 

[Bill B]

I knew what you meant John. As Jenny sounds 'new to this", I just wanted to emphasize the NO IRON point. And Gary rightly called us both on the NPT.

Jenny, I hope that you got the no metal to the tank part. That is the important thing that we are all saying, just differently.

 

[Jenny]

Thanks everybody.  Plastic fittings and Pex-got it is......on with the show.

Jenny

 

[Rene T]

Thanks everybody.  Plastic fittings and Pex-got it is......on with the show.

Jenny

Can you get check valves in plastic if you have a 1 valve bypass system?  That's why I said to use brass. I know check valves for that application does come in brass. My heater uses brass.

 

[Ned]

Sure, check valves can be found in plastic.  That's what we have on our single valve bypass system.  Both the original and the replacements we installed 2 years ago are plastic.