Why does my gas line do this?

SteamtoHotWater

I'm in the process of replacing my steam boiler and water heater with a Laars Combi unit (MFTCW140). The Laars takes a 3/4" natural gas line and will be near where the old steam unit used to be.

Why does my natural gas line take a 20+ foot loop? To my layman's eye, it looks extraneous; though it's obviously quite deliberate. I was planning on just plugging the 3/4" to 1/2" reducing tee that goes to the water heater. Is that okay?

Mad Dog_2

Branches were likely added later.  Natural gas?  No Plugged tees. Any new work or alterations need to be pressure tested., sometimes inspected.  In NYS only licensed Master plumbers or their employees can work on gas piping.  Mad Dog 🐕 

JUGHNE

My guess would be that the NG appliances were installed piecemeal, not all at the same time.

If you have a 1" line coming in and do not want to cut and thread it in place often it is quicker to just do a run around for new hook ups. Lack of a union to change things is often a problem.

The water heater may have been in a different place or not at all, perhaps a tankless coil in the steamer.

Then there is always the answer of "this is what I had on the truck" and don't have to thread anything.

It is always good planning when piping new homes to leave a capped tee or two where there could be future expansion.

SteamtoHotWater

Odd, I thought the answer was going to be some sort of, "minimum length required for piping diameter reduction" regulation/practice/code. That extra twenty foot loop couldn't have been for any sort of appliance, as it runs entirely under the living room. Washer and dryer are located on the other end of the basement. The natural gas steam boiler has been in place since 1972. Before that it was an oil boiler.
So other than future expansion of a gas appliance in the living room, there's no good reason to have the loop? Is it okay for me to leave it in place?

To be clear, I should not plug the 3/4" to 1/2" tee that goes to the water heater?

mattmia2

You might have to replace it all or at least run a separate line for the boiler especially if the combi needs more input than the current boiler to cover dhw at a decent flow rate. That seems like a lot of load for 1" but i did not actually do the load calculations.

Ironman

Replacing a steam boiler with a hot water combi?

You do realize that among other issues that you will probably incur, the output of your radiators will be reduced by at least 1/3?

SteamtoHotWater

Ironman said:

You do realize that among other issues that you will probably incur, the output of your radiators will be reduced by at least 1/3?

I got it covered (hopefully).
I'm taking out the radiators and going with underfloor radiant. I've got a few hundred aluminum plates that I to need install.

I'm still confused as to why I have that extra 20' of gas loop. Guess I'm looking for reassurance that it's not going to harm anything.

Mad Dog_2

I can only speak of the Northeastern USA 🇺🇸,  but we cannot leave any "future" plugged tee connections in a Natural gas line run.  Inspectors want to see any appliances piped out to a plugged or capped shut off cock within a foot or so from that appliance.  

I have had them make us take this piping out and retest, OR call for another final inspection and you'd better have the appliance in place.  All of NYS and I believe NJ, Mass, Connecticut would be very similar.  Mad Dog 🐕 

mattmia2

SteamtoHotWater said:

I'm still confused as to why I have that extra 20' of gas loop. Guess I'm looking for reassurance that it's not going to harm anything.

You need to do the pressure drop calculations. It looks a lot like someone just kept adding stuff on without calculating if the piping could handle the additional load.

SteamtoHotWater

mattmia2 said:

You need to do the pressure drop calculations.

Great, something else I know nothing about.
Can you point me to a guide?

SteamtoHotWater

Thought of another way of phrasing this.
Which of these will likely do the least harm:
a) Put a plug in the 3/4" to 1/2" reducing tee that currently supplies the hot water heater.
b) Fashion a much shorter return, including a 1" to 3/4" reducing tee, from the boiler back to the line that goes to the stove and grill. That is, get rid of most of the 20' of extra pipe. Something like:

Mad Dog_2

The advice above is sound.  Don't want to be a Wet Blanket, but work on Natural Gas is Regulated by the D.O.T.,  State Utilities and local building departments.  Make sure you're in compliance.  With all the recent natural gas explosions, they ain't playing around. Mad Dog 🐕 

PC7060

SteamtoHotWater said:

You need to do the pressure drop calculations.

Great, something else I know nothing about. Can you point me to a guide?

Sure here you go….

https://support.trane.com/hc/en-us/articles/7335301746189-Natural-Gas-Pipe-Sizing-Chart

EBEBRATT-Ed

@Mad Dog_2

I have never heard of not allowing "plugged tees". What do you do if an appliance is removed? Do you have to remove the tee left in the main? Does not sound right. So someone has a gas boiler and a gas HW heater. They remove the HW heater and go to an indirect and have to remove the tee that fed the HW htr?

PC7060

Seems like I’ve read similar posts by @JohnNY; believe it’s required in NYC to mitigate illegal connections (for example hooking up to your neighbors line.  

I’ve got a couple plugged tees on my lines due to rerouting when meter was moved and an unused WH connection. 

Danny Scully

@EBEBRATT-Ed, you’re correct. The expectation would be that the tee is removed completely. You don’t want to make it easier for unqualified people to be able to work on gas. Sound right now? 

SteamtoHotWater

Danny Scully said:

You don’t want to make it easier for unqualified people to be able to work on gas.

Speaking for the unqualified, how much danger am I really in? I don't want minimize the danger of natural gas. But safely putting a plugging an existing tee seems pretty achievable for a cautious DIYer. Shutoff the main, yellow tape, check for leaks - anything else?

EBEBRATT-Ed

@SteamtoHotWater

Agree. I doubt that a plugged tee is a code violation in very many places. That is also why NY did away with dirt legs so no one can hook onto them.

There were pictures on here a few years ago where someone connected to a gas dirt leg with a rubber garden hose and ran it through the basement to another building.

But you can't fix stupid. They (the idiots) will find another way.

realliveplumber

When I put natural gas in my house 20 years ago, I used tees with plugs at every change of direction, and in lieu of couplings. Ran 1 1/2" through the basement.

The inspector said it was not allowed.

I put on a few pressure gauges, and told him they were for the pressure test. He passed it. Lol.

Mad Dog_2

Its not just NYC..Long Island 🏝 it's The Rest of  the State too.  No one is going to stop you from doing anything in your house, but Yes, Ed, you are expected to remove the branch tee and use a Left & Right nipple and coupling to rejoin.  Now, since you disturbed the gas piping, inspectors will usually require a gas pressure test. Only licensed Master Plumbers, employees under their supervision and gas utility workers are allowed to touch anything on natural gas, even removing old piping and plugging a tee.  

This was a bit lax is the past, but since these gas explosion in NYC,  over the last 10 years, The gas utility and AHJ will cut you no slack .  Mad Dog 🐕 

EBEBRATT-Ed

@Mad Dog_2 so i take it that "future" tees are not allowed. I understand what they are trying to prevent but it's going to the extreme.

Mad Dog_2

Yes.  I agree and I learned the hard way years ago.  I had repiped all the gas in a house and didn't have an exact location for the dryer.  I left a plugged tee within like 3 feet of final location for the gas test.  He not only made me take it out, but wouldn't give me the gas cert until dryer was in place.  Anywhere I have worked in NYS, they've enforced it.  Mad Dog 🐕 

TonKa

SteamtoHotWater said:

That extra twenty foot loop couldn't have been for any sort of appliance, as it runs entirely under the living room.

A long gone natural gas space heater or gas lighting, perhaps?

SteamtoHotWater

TonKa said:

A long gone natural gas space heater or gas lighting, perhaps?

I mean, anything is possible but it's just unlikely. This house has always been wired for electricity. It didn't get natural gas until 1972. That loop is sandwiched between the fireplace and a massive 8' radiator. There's no room along the walls for any sort of appliance. If the mystery gas line were to the living room, it would be in the middle of the living space. Looking up at the subfloor, it all looks original and unmolested. Either it's just some really odd pipe work, or there was an appliance in the basement - maybe a natural gas dryer. Though the current electric dryer and all the plumbing is on the other side of the basement. It's a mystery.

I just want to know if there's any harm leaving it in place. That would definitely be the easiest.

ChrisJ

Mad Dog_2 said:

I can only speak of the Northeastern USA 🇺🇸,  but we cannot leave any "future" plugged tee connections in a Natural gas line run.  Inspectors want to see any appliances piped out to a plugged or capped shut off cock within a foot or so from that appliance.  

I have had them make us take this piping out and retest, OR call for another final inspection and you'd better have the appliance in place.  All of NYS and I believe NJ, Mass, Connecticut would be very similar.  Mad Dog 🐕 

In NJ we're allowed tee's with a short nipple and a cap. No plugs, for some reason.

In PA I've seen tees with plugs and inspectors don't seem to care.

clammy

Why don’t you just do it correctly . Cut in a new tees by your meter for your stove and barbecue and then remove all that extra pipe and have then the 1 inch line feeding your new combi or your old steamer and hwh . With that being said as long as the existing gas line has enough capacity for your future combi . Of course a pressure test should be performed upon completion of piping and prior to final connection to the equipment any less is foolish . The main reason I say do it correctly is otherwise you will be looking and living with it forever or until you correct it ,like the Nike motto just do it
Peace and good luck clammy

realliveplumber

ChrisJ said:

Mad Dog_2 said:

I can only speak of the Northeastern USA 🇺🇸,  but we cannot leave any "future" plugged tee connections in a Natural gas line run.  Inspectors want to see any appliances piped out to a plugged or capped shut off cock within a foot or so from that appliance.  

I have had them make us take this piping out and retest, OR call for another final inspection and you'd better have the appliance in place.  All of NYS and I believe NJ, Mass, Connecticut would be very similar.  Mad Dog 🐕 

In NJ we're allowed tee's with a short nipple and a cap. No plugs, for some reason.

In PA I've seen tees with plugs and inspectors don't seem to care.

Where did you get that information regarding NJ?

ChrisJ

realliveplumber said:

ChrisJ said:

Mad Dog_2 said:

I can only speak of the Northeastern USA 🇺🇸,  but we cannot leave any "future" plugged tee connections in a Natural gas line run.  Inspectors want to see any appliances piped out to a plugged or capped shut off cock within a foot or so from that appliance.  

I have had them make us take this piping out and retest, OR call for another final inspection and you'd better have the appliance in place.  All of NYS and I believe NJ, Mass, Connecticut would be very similar.  Mad Dog 🐕 

In NJ we're allowed tee's with a short nipple and a cap. No plugs, for some reason.

In PA I've seen tees with plugs and inspectors don't seem to care.

Where did you get that information regarding NJ?

Multiple inspectors in my area as well as I've done it.

Have you heard otherwise?

SteamtoHotWater

clammy said:

Why don’t you just do it correctly.

Because of the amount of effort? Plugging one tee will take me one minute. Doing what you're suggesting is a day's work, at least.
Is the current setup is definitely "incorrect?" It's been this way for 50 years without issue (that I know of). If all that extra pipe isn't harming anything, or going to affect the performance of my new boiler, I see no reason to take it out.

clammy said:

With that being said as long as the existing gas line has enough capacity for your future combi . Of course a pressure test should be performed upon completion of piping and prior to final connection to the equipment any less is foolish .

I will get the pressure test done.

PC7060

SteamtoHotWater said:

clammy said:

Why don’t you just do it correctly.

Because of the amount of effort? Plugging one tee will take me one minute. Doing what you're suggesting is a day's work, at least.
Is the current setup is definitely "incorrect?" It's been this way for 50 years without issue (that I know of). If all that extra pipe isn't harming anything, or going to affect the performance of my new boiler, I see no reason to take it out.

clammy said:

With that being said as long as the existing gas line has enough capacity for your future combi . Of course a pressure test should be performed upon completion of piping and prior to final connection to the equipment any less is foolish .

I will get the pressure test done.

Agree with Clammy, my concern is piping going out the NG grill is undersize due to the long length. splitting out at meter eliminate the long run and can be done from outside with minimal impact to interior piping.

SteamtoHotWater

PC7060 said:

Agree with Clammy, my concern is piping going out the NG grill is undersize due to the long length.

Of all my worries, my grill doesn't even make the list. I can get it up to 770º and make some really great Neapolitan-esque pizzas. It's my speciality.
I think I've decided to just plug the 3/4" to 1/2" tee that currently leads to my water heater and call it a day. It's by far the easiest solution. If the supply is insufficient to keep my new combi happy, I'll revisit reworking all the pipe.
Thanks to all for the input. Still curious why there's that 20' loop under my living room. But some mysteries are never solved.

mattmia2

The capacity of the piping is determined using math. Specifically one of the procedures in your fuel gas code or a similar procedure. A quick look at the pressure drop table says that 20' of 1" can supply 466,000 btu/hr. It is pretty close to your load at that point and there is another 2/3 of the system past that in smaller pipe so it is likely the piping is undersized as it exists.

Mad Dog_2

Yes.. especially with gas..math matters...(Carbon monoxide issues).  They want a Nipple & cap vis-a-vis a plug, close nipple or street 90, because they feel it has more meat 🍖 on it...less chance of a thin spot that can split and leak.  A solid plug works.  Dope it up and screw it in.  

Who knows why you have unexplained and circuitous gas lines??? There's always the chance the Apprentice did it..or a DIYer.. As long as she's not leaking, deal with it all later.  Mad Dog 🐕 

ChrisJ

Mad Dog_2 said:

Yes.. especially with gas..math matters...(Carbon monoxide issues).  They want a Nipple & cap vis-a-vis a plug, close nipple or street 90, because they feel it has more meat 🍖 on it...less chance of a thin spot that can split and leak.  A solid plug works.  Dope it up and screw it in.  

Who knows why you have unexplained and circuitous gas lines??? There's always the chance the Apprentice did it..or a DIYer.. As long as she's not leaking, deal with it all later.  Mad Dog 🐕 

No bushings either...

PC7060

SteamtoHotWater said:

Agree with Clammy, my concern is piping going out the NG grill is undersize due to the long length.

Of all my worries, my grill doesn't even make the list. I can get it up to 770º and make some really great Neapolitan-esque pizzas. It's my speciality. 

yes, until the grill manages to starve the boiler because the sizing is improper. 

JUGHNE

IIWM, I would connect your new combi to the old steamer tap. Shorter length and larger pipe.

I would nipple/cap the water heater tee.

I feel a nipple/cap seals better than a plug, also easier to open in the future if necessary.

Mad Dog_2

Yes!  No bushings ...unless youre the gas utility...they use a those fittings we just mentioned...mad dog 

ChrisJ

Mad Dog_2 said:

Yes!  No bushings ...unless youre the gas utility...they use a those fittings we just mentioned...mad dog 

They seem to do whatever they want.
Bushings, street ells, literally whatever they want.

Ptfe tape wrapped the wrong way..

realliveplumber

ChrisJ said:

Mad Dog_2 said:

Yes.. especially with gas..math matters...(Carbon monoxide issues).  They want a Nipple & cap vis-a-vis a plug, close nipple or street 90, because they feel it has more meat 🍖 on it...less chance of a thin spot that can split and leak.  A solid plug works.  Dope it up and screw it in.  

Who knows why you have unexplained and circuitous gas lines??? There's always the chance the Apprentice did it..or a DIYer.. As long as she's not leaking, deal with it all later.  Mad Dog 🐕 

The code section reads No cast iron bushings.

Malleable bushings are allowed. All day, every day.

As well as service (street) fittings.

ChrisJ

realliveplumber said:

Mad Dog_2 said:

Yes.. especially with gas..math matters...(Carbon monoxide issues).  They want a Nipple & cap vis-a-vis a plug, close nipple or street 90, because they feel it has more meat 🍖 on it...less chance of a thin spot that can split and leak.  A solid plug works.  Dope it up and screw it in.  

Who knows why you have unexplained and circuitous gas lines??? There's always the chance the Apprentice did it..or a DIYer.. As long as she's not leaking, deal with it all later.  Mad Dog 🐕 

The code section reads No cast iron bushings. Malleable bushings are allowed. All day, every day. As well as service (street) fittings.

Are any cast iron fittings allowed in gas use?

realliveplumber

ChrisJ said:

realliveplumber said:

ChrisJ said:

Mad Dog_2 said:

I can only speak of the Northeastern USA 🇺🇸,  but we cannot leave any "future" plugged tee connections in a Natural gas line run.  Inspectors want to see any appliances piped out to a plugged or capped shut off cock within a foot or so from that appliance.  

I have had them make us take this piping out and retest, OR call for another final inspection and you'd better have the appliance in place.  All of NYS and I believe NJ, Mass, Connecticut would be very similar.  Mad Dog 🐕 

In NJ we're allowed tee's with a short nipple and a cap. No plugs, for some reason.

In PA I've seen tees with plugs and inspectors don't seem to care.

Where did you get that information regarding NJ?

Multiple inspectors in my area as well as I've done it.

Have you heard otherwise?

Respectfully, It doesnt matter what "I've heard". Or what the inspector "says"

There is no code section that says a nipple and cap is required, and that a plug is not an approved means to terminate a connection.