# Replace tank with tankless gas size?



## baron (Nov 24, 2009)

Currently a 40 gal LPG with 1/2" gas supply. Can we install a tankless and get away with this size supply? What are options?


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## pauliplumber (Feb 9, 2009)

Probably not, post an intro!


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## LEAD INGOT (Jul 15, 2009)

call a licensed plumber who specializes in tankless heaters. Hopefully one who has a long list of satisfied tankless customers.


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## user2091 (Sep 27, 2009)

i agree on both!


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## ROCKSTARPLUMBER (Dec 14, 2008)

You can get away with it. GO right ahead. It will work just fine.


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## Tankless (Jun 12, 2008)

A 1/2" line is the correct size to use. Please come back and post pictures of the installation when it's done!!


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## baron (Nov 24, 2009)

*tankless gas supply*

Well thanks for that rockstar. I assume you have the experience here. 
Intro?
Like my name is baron....I am a pc in a small town in norcal. Been that way for 35 years. And can you believe I don't know the answer to the ? I posed?
Frankly I would rather replace the guys WH with the same 40 gal lpg conventional. But the guy is so set on a tankless. I will do it but I am uncertain of the gas supply sizing. I am just about sure the 1/2" supply tees off a 3/4 line not far away but not positive. 
I would be thinking of installing something like a 5gpm unit if I do it.
Regards b


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## LEAD INGOT (Jul 15, 2009)

Omg!


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## ROCKSTARPLUMBER (Dec 14, 2008)

I would go with the Rinnai R-75 unit. Forgive the rudness of these other guys. They dont like it when a non professional plumber comes on the site. Take note, that this is a site for proffessional plumbers only. 

I dont mind helping a fella out from time to time. You can hook that rinnai up to a 1/2 in line. It WILL work. Like Tankless said, if you could, post a picture of it when it is finished!!


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## ILPlumber (Jun 17, 2008)

LP has more btu's of energy compared to the same volume of natural gas. 

1/2" line will work quite nicely. Most plumbers that want to run a larger line to the tankless are just trying to get one over on the customer. The tankless manufacturers assist the plumber in fleecing the homeowner by producing false info in their installation manuals.

That crap just really  me off.


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## LEAD INGOT (Jul 15, 2009)

ILPlumber said:


> LP has more btu's of energy compared to the same volume of natural gas.
> 
> 1/2" line will work quite nicely. Most plumbers that want to run a larger line to the tankless are just trying to get one over on the customer. The tankless manufacturers assist the plumber in fleecing the homeowner by producing false info in their installation manuals.
> 
> That crap just really  me off.


 wow, I guess I don't know as much about tankless heaters as I thought. My Bad.:thumbsup:


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## TheMaster (Jun 12, 2009)

Could you install a water heater near the tankless but dont use it as a water heater...maybe run the 1/2 gas line into it and let it be a gas storage tank to make up for the small pipe size.....then run 3/4 out of the water heater (gas) to the tankless. problem solved? maybe use the old water heater as the new gas storage tank of you wanted to do it on the cheap? I dont know I'm just asking. maybe sombody could help me out.


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## LEAD INGOT (Jul 15, 2009)

I need a drink.


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## user2091 (Sep 27, 2009)

I'm on medication as of 4 min. 20 seconds ago!!!! This is not code.


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## SlickRick (Sep 3, 2009)

bigdaddyplumber said:


> I'm on medication as of 4 min. 20 seconds ago!!!! This is not code.


Pass me some..


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## ILPlumber (Jun 17, 2008)

TheMaster said:


> Could you install a water heater near the tankless but dont use it as a water heater...maybe run the 1/2 gas line into it and let it be a gas storage tank to make up for the small pipe size.....then run 3/4 out of the water heater (gas) to the tankless. problem solved? maybe use the old water heater as the new gas storage tank of you wanted to do it on the cheap? I dont know I'm just asking. maybe sombody could help me out.


Apparently, my gas storage device is somewhere immediately above my buttocks.


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## Ron (Jun 12, 2008)

baron,

Are you a plumber?

Hurry I need an answer fast.


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## LEAD INGOT (Jul 15, 2009)

ILPlumber said:


> Apparently, my gas storage device is somewhere immediately above my buttocks.


 see, God knows how to plumb.


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## baron (Nov 24, 2009)

Are you guys for real? are you joking? I mean...for crissakes... really?


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## Ron (Jun 12, 2008)

baron

You got 30 min to give an intro.


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## GREENPLUM (Jul 27, 2008)

Baron were all a lil screwed in the head around here


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## LEAD INGOT (Jul 15, 2009)

I will take AN ALBUM COVER for a thousand Alex.


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## ILPlumber (Jun 17, 2008)

I think Baron is a plumber Ron.
Of course we are serious. What kind of question is that?


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## Ron (Jun 12, 2008)

Thanks ILP thats all I needed to hear.


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## ILPlumber (Jun 17, 2008)

Baron, 
As Ron stated, please go to the introductions area here: http://www.plumbingzone.com/f3/

I am closing this topic. 

After you introduce yourself such as 


What state?
What code?
How many years in the trade?
What type of plumbing you specialize in?
I will then re-open this topic.

If you are not a plumber please leave, never to return. Go to www.diychatroom.com


Thanks!


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## ILPlumber (Jun 17, 2008)

Ron The Plumber said:


> Thanks ILP thats all I needed to hear.


Just kidding Ron. Time will tell. I know plumbers who would ask this question.


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## Ron (Jun 12, 2008)

Thanks for the intro, thread is reopened.


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## ILPlumber (Jun 17, 2008)

OK,
Ignore all the crap posted before. Go into your NFPA 54 fuel gas code book and look at the tables starting with 6.3a . Size your line from them

Fuggetabout 1/2" line doing it. Unless it is a high pressure system with regs at each appliance.

Either way. The tables don't lie like we do:laughing:


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## ROCKSTARPLUMBER (Dec 14, 2008)

Yea, I missed it. You are going to need a bigger line my pal, or, your going to need more pressure, with regulators at each appliance.


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## TheMaster (Jun 12, 2009)

I did one last week and used 1/2" for the main...55"W.C.:blink: Convert that to psi for me please.:laughing:


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## LEAD INGOT (Jul 15, 2009)

Ok down to brass tacks. The Master brought up a great point. A manometer. What other fixtures are being served, and what are their btu rating? Where will the tankless unit be in orientation to in coming gas. 1st in line, 2nd, 3rd? how many btu's will this unit be fed with when all other fixtures are running at their max btu including friction loss?


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## ROCKSTARPLUMBER (Dec 14, 2008)

Got to figure Baron, that whatever tankless unit you use, the BTU load is going to be close to triple, and thats for a small one like you mentioned.


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## Tankless (Jun 12, 2008)

TheMaster said:


> I did one last week and used 1/2" for the main...55"W.C.:blink: Convert that to psi for me please.:laughing:


 
Exactly. Doesn't pass my smell test.

C-36 for 33-34 years and can't size a gas line? Please.

So Baron, does this mean you won't be posting the pictures now?


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## ILPlumber (Jun 17, 2008)

TheMaster said:


> I did one last week and used 1/2" for the main...55"W.C.:blink: Convert that to psi for me please.:laughing:


1.98 psi


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## Ron (Jun 12, 2008)

Did we scare baron away, come on baron, you have to answer these tech question if you need our help.


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## Tankless (Jun 12, 2008)

ilplumber said:


> 1.98 Psi


 
1.99 Lol


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## TheMaster (Jun 12, 2009)

Theres noway anyone can help him with that info without knowing everything about that system. Even if the line is 1/2" high pressure its lenght matters and even if its within the BTU lenght limits whats going to happen when all the other appliances are burning? You hafta add the entire expected demand and size from there. You might hafta make a new run all the way back to the main source...not the main line.


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## ILPlumber (Jun 17, 2008)

Tankless said:


> 1.99 Lol


I had 27.7 on the brain. 

Now I'm going to have to look it up. I hate remembering stuff wrong.

Yup you were right. 55 Water Column [inch] = 1.9870010505 pound/square inch


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## LEAD INGOT (Jul 15, 2009)

TheMaster said:


> Theres noway anyone can help him with that info without knowing everything about that system. Even if the line is 1/2" high pressure its lenght matters and even if its within the BTU lenght limits whats going to happen when all the other appliances are burning? You hafta add the entire expected demand and size from there. You might hafta make a new run all the way back to the main source...not the main line.


 Hence my barrage of questions.


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## TheMaster (Jun 12, 2009)

1.98 is what the engineers tool box says....and 2psi =55.4" w.c.


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## bigdaddyrob (May 14, 2009)

W.C to Psi, I am starting to flash back to my JY Test...damn it now I am gonna break out the book... lol

Maybe b-c I haven't been doing it forever, but I will always bust out the Gas Book and graph paper and lay it out when adding something completly new to a system. Actually I think we are required by code to provide this, altho I have never had an inspector ask for it. But I keep all mine just for my own knowledge ( knowledge = cover my ass insurance )


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## Tankless (Jun 12, 2008)

bigdaddyrob said:


> W.C to Psi, I am starting to flash back to my JY Test...damn it now I am gonna break out the book... lol
> 
> Maybe b-c I haven't been doing it forever, but I will always bust out the Gas Book and graph paper and lay it out when adding something completly new to a system. Actually I think we are required by code to provide this, altho I have never had an inspector ask for it. But I keep all mine just for my own knowledge ( knowledge = cover my ass insurance )


 
I used to do it all the time. I would calk out every fixture including pressure drops. Than one time I handed my paperwork to an inspector, once he got to my drawing / calk page, he turns to me and asked what this was. That was the last time I ever provided it....I honestly think they don't know how to do it themselves. I could just write in whatever I wanted and those idiots still wouldn't know the difference. I still do them for multi unit tankless installs.


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## para1 (Jun 17, 2008)

TheMaster said:


> Could you install a water heater near the tankless but dont use it as a water heater...maybe run the 1/2 gas line into it and let it be a gas storage tank to make up for the small pipe size.....then run 3/4 out of the water heater (gas) to the tankless. problem solved? maybe use the old water heater as the new gas storage tank of you wanted to do it on the cheap? I dont know I'm just asking. maybe sombody could help me out.


 
You're right MASTER .I have somrthing similar on the farm. Capturing wasted off gas (methane ) from our cows, locking them in a dome I built, compressing it and using the gas to light outdoor Christmas lights.:thumbsup:


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## para1 (Jun 17, 2008)

Ron The Plumber said:


> baron
> 
> You got 30 min to give an intro.


" What is this, an episode of ...24?"


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## Ron (Jun 12, 2008)

para1 said:


> " What is this, an episode of ...24?"


He done gave an intro. so it is ok now.


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## Protech (Sep 22, 2008)

How do you collect the methane? hose inserted in cows rectum with a solar powered compressor and tank on the cows back??



para1 said:


> You're right MASTER .I have somrthing similar on the farm. Capturing wasted off gas (methane ) from our cows, locking them in a dome I built, compressing it and using the gas to light outdoor Christmas lights.:thumbsup:


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## Redwood (Sep 8, 2008)

Protech said:


> How do you collect the methane? hose inserted in cows rectum with a solar powered compressor and tank on the cows back??


Dummy You use Balloons like this one and collect them when full... :laughing:


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## Protech (Sep 22, 2008)

wont the cow float away?


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## ROCKSTARPLUMBER (Dec 14, 2008)

Redwood said:


> Dummy You use Balloons like this one and collect them when full... :laughing:



I think thats TM. The guy on the left in the white and checkerd looking sweater. I would get beat up constantly if I wore a sweater like that.:laughing:


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## Redwood (Sep 8, 2008)

Protech said:


> wont the cow float away?


Not if you collect the balloon in time.:laughing:


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## Airgap (Dec 18, 2008)

Redwood said:


> Dummy You use Balloons like this one and collect them when full... :laughing:
> 
> Snuck right by 2K posts without Ron noticing didn't ya Red?? That's a lot of advertising for that book of yours....:thumbup:


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## Redwood (Sep 8, 2008)

Airgap said:


> Redwood said:
> 
> 
> > Dummy You use Balloons like this one and collect them when full... :laughing:
> ...


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## Airgap (Dec 18, 2008)

Funny stuff right thar....^^^^


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