Do I need 12” vertical brass stubs on this Rheem Water Heater?

Users who are viewing this thread

Borisj

In the Trades
Messages
14
Reaction score
1
Points
3
Location
Texas
Hello, I’m installing a Rheem Marathon 50-gal water heater, in a 2nd floor, where it’ll service only the 1st floor (so it kinda has a “built in” heat trap since the pipe only goes down). Been trying to contact Rheem for 2 weeks with no response. There’s no code official here for me to ask either (unincorporated area). I want to follow best practices to ensure safety and performance.

1) The manual says "pre-solder 12" minimum stub pipes before installing to unit." We don’t use copper here due to water composition. I could use a brass nipple, but I want to be sure I understand the purpose of this requirement. Is it:

-(a) to ensure vertical clearance (which I’ll have regardless)

-(b) to ensure that a plumber does not melt plastic components while soldering < 12" from the inlet/outlet (irrelevant to me)

-(c) to make sure there is not a pressure "bottleneck" at the tank whether for safety or water pressure issues (good reason!)

-(d) some other reason?

2) If I *do* need to put 12” of brass here... does it have to be vertical? Or could I instead attach a brass street elbow directly to the inlet/outlet, then put the brass nipple horizontal? Again I don’t want to mess with water pressure or safety.

--And if it *does* have to be vertical, then why Terry ok here?
(I trust him over the manual that came with my heater, which is generic for all Rheem tank models). Thing is, my installation will be all hard piped.

3) The unit is being plumbed with PEX-A (Uponor) which is rated for direct connection to a water heater. Manual p. 8 says "Hot water connection fitting must have an ID > 0.725”." I can accomplish that with a 3/4" brass nipple, which I will then adapt to PEX-A (0.681" ID) - but is there a minimum length required for that nipple?

Not trying to cut corners at all – just want to do what’s best in this situation. Thanks!
 

Reach4

Well-Known Member
Messages
36,629
Reaction score
3,898
Points
113
Location
IL
When you have a WH servicing a lower floor, you need a vacuum breaker.
 

John Gayewski

In the Trades
Messages
2,941
Reaction score
789
Points
113
Location
Iowa
18" of hard pipe is the rule for most codes. Yes it's a saftey thing for a runnaway water heater situation.
 

hj

Master Plumber
Messages
33,540
Reaction score
989
Points
113
Location
Cave Creek, Arizona
Website
www.terrylove.com
In a "run away heater situation" 18 " brass pipes will do NOTHING to salvage the destruction. It is it insure that PEX, and similar products are not connected too close to the water heater.
 

Terry

The Plumbing Wizard
Staff member
Messages
29,939
Reaction score
3,400
Points
113
Location
Bothell, Washington
Website
terrylove.com
If flexible water connections are used, the must comply with the standard for flexible Water Connectors, ASME A112.18.6/ CSA-B125.6. The HOT and COLD water connections are clearly marked on the water heater.

SOLDER WITH CARE!!! If sweat connections are used, DO NOT apply heat directly to any component directly connected to the water heater. Assemblies should be built to a minimum length of 12” before attaching to any connection on the water heater to avoid damaging the unit.

So the flex connectors are the easy way to do it according to Rheem's instructions.
They have flex in Stainless Steel and in copper.

18" have been mainly for "GAS" water heaters, I would guess because there is a chimney they are close to. An electric water heater doesn't have that. I have seen where they sometimes get connected to PEX.

 
Last edited:

Borisj

In the Trades
Messages
14
Reaction score
1
Points
3
Location
Texas
Thanks so much Terry & hj, my plumbing tutors over the past 10 years, for responding to this long time lurker :) I'm a framer by trade but do a lot of off the books plumbing as it comes up.

Terry -- I want to avoid flexible hoses in this case. And I can't use copper w/our water composition. So, since I can't start w/PEX-A, is it safe (and won't reduce water pressure) for me to start with a brass street elbow, then a 12" brass nipple, then PEX? Or will the elbow create a bottleneck?

hj -- Uponor Pex A is rated for direct connection to water heaters. Should I not trust that? Just want to do what's right here, but also don't wanna spend an extra $50 on 3/4" x 12" lead free brass nipples when I don't need to (again, copper is not an option here).
 

Jeff H Young

In the Trades
Messages
6,099
Reaction score
1,385
Points
113
Location
92346
I've never run PEX to a w/h but ran CPVC and my opinion is keep the plastic inside the walls and stub out copper. costs more but cleaner job.
I believe that if manufacture says you need 12 inches then the code would require you follow that. usually if a code is more lenient the the manufacture instructional requirements you must adhere to more stringent of the 2. probably need a vacuum relief valve as well.
I have no opinion on energy saving tips other than insulate first 6 ft of cold and and hot minimum per my CA code
 

Terry

The Plumbing Wizard
Staff member
Messages
29,939
Reaction score
3,400
Points
113
Location
Bothell, Washington
Website
terrylove.com
I believe that if manufacture says you need 12 inches then the code would require you follow that. usually if a code is more lenient the the manufacture instructional requirements you must adhere to more stringent of the 2.

The reason for 12" of copper was that they didn't want you to solder near the plastic outer shell of the Marathon water heater.
If you solder, keep it 12" away, not you must solder and have a 12" copper connection.
The Rheem instructions allow you to use flexible connections.
 

Jeff H Young

In the Trades
Messages
6,099
Reaction score
1,385
Points
113
Location
92346
flex connectors in my state legal , soldering withen a certain distance of plastic does not apply to installing plastic to a previously soldered connection. Im not sure whether you can connect plastic directly to W?H never done it its cheap and easy I suppose if I ran a lot of plastic Id know for those times when trying to go low budget, I see it on t and ps too
 

Borisj

In the Trades
Messages
14
Reaction score
1
Points
3
Location
Texas
The reason for 12" of copper was that they didn't want you to solder near the plastic outer shell of the Marathon water heater.
If you solder, keep it 12" away, not you must solder and have a 12" copper connection.
The Rheem instructions allow you to use flexible connections.
Terry I can't use copper here (water composition), and I don't want to use flexible (unless corrugated copper... which I can't use). I want to hard pipe. So I think I have to use brass nipples... but if I do, is it ok to start with a street elbow? or could that cause a pressure issue to put a elbow right at the inlet/outlet?

Also everyone: this water heater has a built in vacuum relief valve so don't worry
 

Jeff H Young

In the Trades
Messages
6,099
Reaction score
1,385
Points
113
Location
92346
Corrugated stainless steel? Nipple and 90 won't work why street 90. if your piping isn't grossly undersized a street 90 won't break the camels back and cause low flow
 

Terry

The Plumbing Wizard
Staff member
Messages
29,939
Reaction score
3,400
Points
113
Location
Bothell, Washington
Website
terrylove.com
The only reason for hard pipe being 12" is if you're soldering near the tank. You're making it way harder than it is.
Fittings are fine to use. Your dip tube is smaller than anything you can install there anyway.
Flex can also be had in stainless. I think Master Plumber Mark uses a lot of stainless flex on his installs in Indiana.
 

Borisj

In the Trades
Messages
14
Reaction score
1
Points
3
Location
Texas
The only reason for hard pipe being 12" is if you're soldering near the tank. You're making it way harder than it is.
Fittings are fine to use. Your dip tube is smaller than anything you can install there anyway.
Flex can also be had in stainless. I think Master Plumber Mark uses a lot of stainless flex on his installs in Indiana.

Just trying to learn here. I have installed 10-12 water heaters and always just used flexible connectors as is standard here. I wanted to do something more resilient on this project. The inlet/outlet on this water heater are brass, that's also why I wasn't thinking stainless.

I have seen dip tubes 3/4" diameter so I am not sure if the dip tube is smaller than the 3/4" brass elbow I'd attach. I just know the water is coming out high pressure and don't wanna create a safety or pressure issue is all.
 

John Gayewski

In the Trades
Messages
2,941
Reaction score
789
Points
113
Location
Iowa
In a "run away heater situation" 18 " brass pipes will do NOTHING to salvage the destruction. It is it insure that PEX, and similar products are not connected too close to the water heater.
Wrong. The T&P will feel the pressure and temp before the piping will, as long as there is 18" of hard pipe.

Without it the steam heat and pressure can effect the piping connected to the water heater. The chimney is not a factor. Although maybe some inspectors might let some get away with hooking PEX to a water heater you don't want floppy noodles spraying steam and whipping around in every direction.
 

Borisj

In the Trades
Messages
14
Reaction score
1
Points
3
Location
Texas
Wrong. The T&P will feel the pressure and temp before the piping will, as long as there is 18" of hard pipe.

Without it the steam heat and pressure can effect the piping connected to the water heater. The chimney is not a factor. Although maybe some inspectors might let some get away with hooking PEX to a water heater you don't want floppy noodles spraying steam and whipping around in every direction.
So are you saying that all water heaters should be installed with 18" of hard pipe? I have never seen this in TX in my life, except old copper installs. I have also never seen it specd in a Rheem or AO manual. Just asking if it's best practice. Does the hard pipe have to be vertical?
 

John Gayewski

In the Trades
Messages
2,941
Reaction score
789
Points
113
Location
Iowa
So are you saying that all water heaters should be installed with 18" of hard pipe? I have never seen this in TX in my life, except old copper installs. I have also never seen it specd in a Rheem or AO manual. Just asking if it's best practice. Does the hard pipe have to be vertical?
Its code for a reason. Electric or gas waters. I don't know why you've never seen this and frankly it doesn't mean much that you haven't.

There are plenty of products made to conform to this requirement
 

Terry

The Plumbing Wizard
Staff member
Messages
29,939
Reaction score
3,400
Points
113
Location
Bothell, Washington
Website
terrylove.com
On the West coast we use flex connectors because we are in the earthquakes. Every state has their own codes. A lot of places allow a direct connection with PEX for electric water heaters and at least 18" of metal if it's a gas water heater.
 

Borisj

In the Trades
Messages
14
Reaction score
1
Points
3
Location
Texas
Its code for a reason. Electric or gas waters. I don't know why you've never seen this and frankly it doesn't mean much that you haven't.

There are plenty of products made to conform to this requirement
Hi John, I'm not saying it "means much." I haven't seen it because I'm a professional framer and remodeler, and I'm hear to LEARN. As Terry said above, it's not done in his area for earthquakes. And I have laid eyes on maybe 100 water heaters in TX and can verify that it is not the norm here. HOWEVER I am happy to do it if it is the right thing to do. I'm also asking if you share Terry's opinion that it's fine for me to start my run with an elbow.
 

Borisj

In the Trades
Messages
14
Reaction score
1
Points
3
Location
Texas
Also I just found this thread: https://terrylove.com/forums/index....for-electric-water-heater-connections.76471/#. MikeQ's reply is interesting. In tandem with the above, it honestly seems like no one really knows what the answer is. The applicable code in every jurisdiction doesn't require 18" hard pipe even if UPC does. Rheem itself says PEX to an electric tank water heater is ok... in a different product's manual. But again I am just trying to figure out best practice
 

John Gayewski

In the Trades
Messages
2,941
Reaction score
789
Points
113
Location
Iowa
Also I just found this thread: https://terrylove.com/forums/index....for-electric-water-heater-connections.76471/#. MikeQ's reply is interesting. In tandem with the above, it honestly seems like no one really knows what the answer is. The applicable code in every jurisdiction doesn't require 18" hard pipe even if UPC does. Rheem itself says PEX to an electric tank water heater is ok... in a different product's manual. But again I am just trying to figure out best practice
The thing your mistaken on is "no one knows" best practice is 18" of metallic pipe to and from the water heater. What Terry said is that they use flex connectors, which are metal.

Best practice is known. Metallic hard pipe to the water heater. If earthquake area metallic flex connectors with the water heater strapped to the wall. That is best practice. I'm surprised no one has given you a link, but the metallic flex comnectors are becoming the go to. Pretty much no pro plumber would hook PEX to a water heater, but it takes all kinds.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks