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-   -   Which is the best pipe to run for a 2 NORITZ NG 300K BTU tankless heater install. (http://www.diychatroom.com/f7/best-pipe-run-2-noritz-ng-300k-btu-tankless-heater-install-26283/)

Philip_Soldat 09-04-2008 05:26 PM

Which is the best gas pipe to run for a 2 NORITZ NG 300K BTU tankless heater install.
 
Hi, I am installing 2 NORITZ NG 300K BTU tankless waterheaters in my laundry room. There is a gas line hidden somewhere in the wall that feeds my HVAC unit with a copper flexpipe. I dont want to mess with that outlet, as it seems that I have a 1.5 inch outlet on top of the meter that feeds a fireplace with a copper line outside my house.

My project consists of running a new pipe from the meter to the laundry room, which is about 20 feet away to supply 600K BTU for the heaters, 150K BTU for a stove that I am putting in the laundry as well, and another connection for the fireplace line that I took off to install this new pipe for the laundry supply. Total projected BTU is about 900K.

My question, is that I would like some advice on the best premium choice of pipe to run from the meter to the laundry, where its going to branch off to the appliances. My calculations call for a 1.25 line. Its pretty much a straight shot from the meter to the laundry room with no bends, the only thing is that it will run in the ceiling, so I have to check codes if this is OK.

Thank you in advance.

Marlin 09-04-2008 06:34 PM

First I would recommend against a DIY gas piping job especially if you have little experiance. We aren't talking about flooding your house as a worst case senario, we're talking about literally blowing your house us as a worst case senario. Check with your town to see if you are allowed to do this work without a license and find out if you need a permit for it.

You will need to use threaded black pipe, flexible stuff isn't going to cut it. You will also need a larger line then 1 1/4. You then need to do a pressure test on the lines for 24 hours before you turn the gas on.

Termite 09-04-2008 07:01 PM

Why on earth would you put 2 tankless units in a house?

We need more info. Need your total btu/h load on the entire house, every single fixture, not just the new stuff. If you're not sure of exact btu/h, list out what there is and we can approximate the load. Then I need the distance from the meter to the farthest gas appliance in the house. Could be the new water heaters, could be a fireplace, etc. That measurement is used to size every piece of pipe in the house. Honestly, I doubt that 1-1/4" will get it done.

For DIY work, black iron is basically the standard. If you aren't an accomplished plumber, I would advise against attempting the installation of the gasline and especially the tankless units yourself.

Philip_Soldat 09-04-2008 09:28 PM

Well, I need 20 GPM of constant flow for my spa set-up and it looks like a multisystem set up was the way to go for me.

Also, I just re-checked and my two other appliances (stove/fireplace) will be pulling under 100K BTU total, so total pull here is 700K BTU.

I need the main pipe to go 20 feet in a straight line, where it will branch 5 feet to the 80K stove. At the point of this branch, I need the main pipe to then make a 90 degree turn and then go another 5 feet, where it should branch to two 3/4 inch outlets to the heaters (the units are 5 feet from where the main pipe ends) and the fireplace, which is behind the next wall about 5 feet away.

So to run that backwards, fireplace and heaters 5 feet to the main pipe, then 5 feet of main to the stove split (5 feet away from main pipe)...then 20 feet to the meter.

Just curious, but why is this perceived so difficult and why is the first assumption when people ask questions that they are imbeciles and cannot do a competent job.

Also, what about the stainless setup? Can't stainless be tapped?

Marlin 09-04-2008 10:13 PM

Because obviously you have no experiance doing this. No one here is going to inspect your work and you're most likely not going to get it inspected by the town as most require a license to do this type of work. No one wants to see you screw up and kill yourself and your family.

Philip_Soldat 09-04-2008 10:23 PM

Ok, thats understandable, but I am operating under the assumption that a reasonable person such as myself will get a permit and an inspection for such a project.

Termite 09-04-2008 10:25 PM

Quote:

Originally Posted by Philip_Soldat (Post 155134)
why is the first assumption when people ask questions that they are imbeciles and cannot do a competent job.

What a ridiculous statement you've made. Nobody called you an imbecile, nor did anyone assume you are one.

As Marlin said, a question as elementary as the one you asked about pipe type indicates to anyone with experience installing gaslines and tankless water heaters that you don't have any. You're talking about fuel gas, which will kill you. You were being given sound advice by two people that have nothing to gain, and if you re-read my post, I was more than willing to help you through this.

Termite 09-04-2008 10:28 PM

700000 btu/h's at 30' of pipe, right? Checking........

Termite 09-04-2008 10:32 PM

1-1/4" pipe barely makes it, but it makes it. Maximum capacity would be 77000 btu/h's @ 30'. That's per 2003IRC table G2413.4(1) for schedule 40 metallic pipe, natural gas, .5 psi or less inlet pressure, .5" water column, and a specific gravity of .60.

Glad you're pulling a permit. Always a good thing to do.

Call the inspector before piping and make sure he agrees with the specs I've given you. Gas pressures, water column, specific gravity, and rules vary by region and gas supply company.

Termite 09-04-2008 10:35 PM

Quote:

Originally Posted by Philip_Soldat (Post 155134)
Also, what about the stainless setup? Can't stainless be tapped?

I don't understand what you mean here. Stainless what?

Philip_Soldat 09-04-2008 10:51 PM

^^^ Sorry the manufacturer mentioned to use stainless for gas piping whenever possible, that is why I guess I was confused in the first place, but black iron it is then.

Philip_Soldat 09-04-2008 11:06 PM

Quote:

Originally Posted by thekctermite (Post 155166)
1-1/4" pipe barely makes it, but it makes it. Maximum capacity would be 77000 btu/h's @ 30'. That's per 2003IRC table G2413.4(1) for schedule 40 metallic pipe, natural gas, .5 psi or less inlet pressure, .5" water column, and a specific gravity of .60.

Thank you so much for your time!

Quote:

Originally Posted by thekctermite (Post 155166)
Glad you're pulling a permit. Always a good thing to do.

Yeah I'm worried not only about the permit but also will call insurance and make sure everything is squared away, I want to make sure everything that I am working on from electricity to the gas/water plumbing is covered, once the inspections are passed. Here in Virginia there is a lot of freedom of what a homeowner can work on, but they are very strict when it comes to illegal work.

Quote:

Originally Posted by thekctermite (Post 155166)
Call the inspector before piping and make sure he agrees with the specs I've given you. Gas pressures, water column, specific gravity, and rules vary by region and gas supply company.

I sure will do!

So do you recommend a size up on the pipe? I'm affraid that the coupling on the meter is only big enough for a 1.25 pipe. The inside hole diameter of the coupling is about 1.25, I assume you cannot go up a size if the coupling is smaller then the pipe you're running even if its one size apart. Thanks again.

Termite 09-04-2008 11:08 PM

The manufacturer probably means corrugated stainless steel tubing (CSST), which is sold under the brand names WardFlex, TracPipe, and GasTite. It is largely unavailable through retailers, and is not a DIY product. Many tankless installations are done with CSST, although there's not necessarily an advantage to it other than the fact that it is a faster installation.

Philip_Soldat 09-04-2008 11:15 PM

Ok gotcha... i was just worried that the iron was gonna flake over time and perhaps damage my heaters. Hopefully not with traps. thanks again!

Alan 09-04-2008 11:19 PM

Isn't black iron more expensive than galvanized? :huh: We're allowed to use galvanized here for gas as well as long as it's above ground. Actually cannot use black OR galvanized underground unless it's wrapped, otherwise have to use coated pipe.

Check with your local inspector to make sure.

P.S. I'm with kctermite on CSST. Very very very expensive by the foot, and the fittings start out in the 40-50 dollar range and go up from there. Now you're talking 1-1/4 to 1-1/2 pipe, i'm guessing those fittings are up over 2 or 3 HUNDRED each. At any size, galvanized or black iron wins at sheer material cost.


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