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-   -   stubbing out hotwater heater? (http://www.diychatroom.com/f7/stubbing-out-hotwater-heater-144775/)

rtoni 05-24-2012 09:49 PM

stubbing out hotwater heater?
 
hi - I have 3/4" PEX run up thru the floor in the wall cavity for my hot water heater. I have not yet figured out which water heater / model I need to install - it will be electric (no gas out there, maybe consider propane one day but not right now). I have no clear idea how to rough in the pipe connection to the heater - the walls will be covered with drywall once the plumbing is complete. Right now it's just a couple pex runs (hot and cold) inside the wall cavity, capped off and accessible.

1)Is there a standard height at which the water heater line rough in would exit thru the wall? Or is it completely dependent on the tank size / height, etc.?

2)Should I stub out the line with copper, or just add a 90 to the pex and extend it thru the rough opening for the water heater? I don't want a "floppy" or loose connection coming out of the wall. I used copper to stub out a couple of other fixtures, then transitioned to PEX in the crawl area - and all these rough ins are clamped down and rock solid. No movement when I open or close one of those valves e.g. under the sink or vanity. How can I do this with PEX only or should I not even worry for the water heater?

3)I'm understanding that I can't use pex to connect directly to the heater supply nipples - I'm thinking of just using those 3/4 flex connections to run from the supply to the tank. My other (home) water tank has copper all the way to the tank, done by a pro plumber, no flex lines. Is there anything wrong with the flex line option?

4)Should I install a shut off valve on both lines (hot and cold) or just one? if only one then which one?

5) we are 3 people (me/ wife/son), doing cold water laundry, pretty much seasonal, just 1 bathroom with shower only (no tub) and I can't remember the last time anyone took showers back to back. I'm thinking maybe 40 gal is overkill even though there are some recommendations here in other posts to go that size as a minimum. I see a 22 gal tank on sale right now and tempted to scoop that up. Thoughts?

lotsa questions - thanks very much in advance for any replies and advice.
-randy

joecaption 05-24-2012 09:51 PM

Go with a 40 gal. tank, only need one shut off to the incoming cold side.

rtoni 05-24-2012 09:58 PM

joecaption - wow - a record braking response time - thanks very much for chiming in right away!

TheEplumber 05-24-2012 10:15 PM

1. A rough in height escapes me right now- sorry. defiantly above your heater though:yes: Have you considered room for an expansion tank if required?
2. Stub out copper
3.I use the flex lines because I can. Other plumbers will disagree. check your code. I cannot connect PEX to a heater. Must be 18" developed length away
4. Most homes only valve the cold side. Commercial work- usually both. your choice.
5. My choice would be 40 gal
Have you planned your t&p valve piping? What is your code requirement?

rtoni 05-25-2012 09:36 AM

Hey EPlumber thanks for the reply. Good question re t&p - I haven't planned anything for the run so far - I'm not sure what the code requirements are (Ontario, Canada) - maybe someone here can help me out with that? I'm wondering if I can just run this to my sump pit in the crawl space? that would be easy, if it makes sense.

Re: expansion tank - another thing I'm a bit clueless about - my system is fed from underground cistern (we're out in the sticks) - I use a shallow well jet pump with 2 bladder tanks hooked up in-line, and the current pressure switch is set to cut off at 40 psi, and there's also a pressure relief valve installed right at the tank tee. This valve drains into the sump pit in the crawl space via simple run of garden hose right now - poor man's solution :-). Would an expansion tank at the water heater still be a consideration given this setup?

rjniles 05-25-2012 10:13 AM

You do not need an expansion tank with a well pump system- your pump expansion tank performs the same purpose.

Most standard 30 - 50 gallon WHs are about 55" tall, bring your rough-outs about 8-15" above that. If for some reason (usually space limitations) you are planning on using a low-boy or a tall WH, you will have to make adjustments.

Plumb the T&P valve down to the WH drip pan. Plumb the pan to the sump.

Alan 05-25-2012 10:18 AM

We go 68" off the floor.

What that equates to is about 8" above the heater. That will give you room to have an 18" flex on it without being too short on the hot side.

rtoni 05-25-2012 10:25 AM

Alan / rjniles - thanks for the clarification and the additional info - much appreciated.

I think I have everything I need to plan this out now (except, of course, the tank :laughing:). Thanks again everyone! Great forum...

TheEplumber 05-25-2012 11:12 AM

Quote:

Originally Posted by rjniles (Post 928474)

Plumb the T&P valve down to the WH drip pan. Plumb the pan to the sump.

I used to do this. Now my inspectors won't allow it. T&P should join the indirect waste pipe after the pan. It is then up sized two pipe diameters to allow for the sudden pressure dump of an open T&P valve. Or we pipe the T&P directly outside.

rtoni 05-25-2012 11:50 AM

Quote:

Originally Posted by TheEplumber (Post 928497)
I used to do this. Now my inspectors won't allow it. T&P should join the indirect waste pipe after the pan. It is then up sized two pipe diameters to allow for the sudden pressure dump of an open T&P valve. Or we pipe the T&P directly outside.

sorry if I'm not understanding this, but in this scenario does this mean the pan could still be plumbed to my sump, but with t&p connecting to the same run as opposed to just dropping down into the pan? the outside option also seems interesting - the tank will be within a few feet of an exterior wall. Any special considerations there if I just push the pipe outside right thru the wall?

TheEplumber 05-25-2012 12:27 PM

Quote:

Originally Posted by rtoni (Post 928522)
sorry if I'm not understanding this, but in this scenario does this mean the pan could still be plumbed to my sump, but with t&p connecting to the same run as opposed to just dropping down into the pan? the outside option also seems interesting - the tank will be within a few feet of an exterior wall. Any special considerations there if I just push the pipe outside right thru the wall?

Yes, I join the two together using a 11/4x3/4x3/4" tee outside of the pan and pipe to the sump. I run the combined line in 1.25" min. pipe to handle the T&P discharge. Again, this is my local code requirement. Maybe not in your area.
As for piping to the exterior, it should terminate outside, at least 6" above ground and have a elbow pointing down- preferably with no threads so some dumbo doesn't thread a cap or plug on it when it starts dripping. The drawback to piping outside is cold climate conditions. If the T&P should ever start dripping and it ices shut, then you've effectively capped the pipe and created a steam powered rocket :eek: Check out Youtube for WH explosions.
Piping reliefs really depends on your inspectors. I have seen many effective methods. And if you maintain the heater properly chances are the pan and T&P will never be used.

rtoni 05-25-2012 01:03 PM

Outside is a freeze issue where I am. So likely I'll just keep everything inside.

thanks again TheEplumber and everyone...

rtoni 05-28-2012 04:24 PM

I got my 3/4 water lines (pex to copper) installed and stubbed out this weekend. I put a ball valve on the cold water side and threaded connections on both ends to hook up to flex lines above the tank. I almost grabbed the stainless steel braided connections on the way out but I hesitated. The local HD sells these:

http://www.homedepot.ca/product/stai...nnector/924699

The reason I hedged is that the building supply store across the street carries another brand for @ $6 or $7 each, as opposed to almost $25 each for the Watts.

One difference I could see is the fact that the Watts connectors appear to have the plastic sleeve in the ends (dielectric?) but I'm not sure I need this since the tank I'm looking at has the dielectric nipples. Is this correct?

The Watts brand "felt" like a heavier / better quality, whereas the other brand just seemed like a 3/4 " version of any other flex line (toilet, vanity, etc.). Apologies as I can't recall the brand name for the other (cheaper) units but the fact that they are about a quarter the price of the Watts leaves me wondering if it's really overkill to spend $50 on 2 flex connections when I hook it up for $12?

rjniles 05-28-2012 04:45 PM

TThis the the type flex I prefer, a lot less that $25 each.

http://www.plbg.com/imagesspec/3-17-2012.jpg

rtoni 05-28-2012 04:58 PM

Thanks rjniles - I've never worked with the corrugated flex lines - is that available in the box stores?


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