Gas line pool heater gas pipe sized wrong?

heathead

Pool heater gas line installed by licensed contractor. 400,000 btu natural gas heater. All 1/2 psi lines no regulators before or after gas line, only one that steps down gas line street pressure to 1/2 psi before meter. The meter was used to run pool heater before it was moved, so I know it's big enough for the pool heater. They ran about 35 feet 3/4 black threaded steel pipe with a qty of 5 90's. How can this work ? What am I missing that makes this work. The heater needs min 6 inches wc. In the process they went through brick wall no sleeve. Doesn't black pipe need to be sleeved when going through brick work. Then it goes under ground with what looks like regular 3/4 copper type L with 2 90's soldered not brazed. I guess that under ground the joint won't get hot and melt in fire. How does this happen with a reputable contractor. Doesn't a person with master gas license have to look at what their workers do. Shut off gas to pool heater pilot was drafting out the side when running with very yellow flame from pilot when running. How can the fuzzy math work to get 400,000 btu through 3/4.

Charlie from wmass

it can not. Soldered copper for gas? A gas inspector is required for work done in Massachusetts where is this done, perhaps someone local to there can give some input.

Rich_49

How many inches water column is the regulator at the meter set for ? Max TDL for 3/4 with an 8" wc regulator and 1/2 pd through the meter would be 24 feet . If this line was 1" he could've gone a TDL of 78.9 ' . This is assuming similar conditions to what my local utility provides .

EBEBRATT-Ed

Very doubtful that it is done right. Did this get inspected I never herd of gas lines being soldered for obvious reasons? Permit?

4Johnpipe

Can you call the building department now or was this done a while ago? Post some pictures...

heathead

Thanks for all the thoughts. The owner Is trying to get them to come back. The work was just done. The copper is painted now with gray paint. Tells you that a little matching gray paint makes people think it was done right. I know it was soldered and not brazed, I saw it before it was painted and you can tell by the solder drip. They used a threader for the 3/4 black pipe and the rest looks good ie shut offs and unions and no flex connector into cabinets. Still think it needs a sleeve through brick work. If the meter is set up for 1/2 psi and 6 inch min wc operation for the pool heater any way that changes pressure drops to make the 3/4 pipe work. The meter couldn't be set higher than 1/2 because the other appliances don't have a separate step down regulator. I Don't think it should be discussed here but some day I want to learn how one chooses what pressure drop charts one could use. I use the .5 drop it is a chart that i know I am safe with. Does one choose the pressure drop of a chart based on the supply wc vs min operating wc of the load and that being the acceptable drop difference. I will let you know when they come back hopefully it is taking a long time for them to call back because the person with the gas fitters license is going to have to come out. Thanks.

Rich_49

Grab yourself a copy of the IFGC if that pertains to your area . See section 402.5 . Read and understand ALLOWABLE PRESSURE DROP . If you use the IRC for gas , that is all excerpted from the IFGC book , word for word .
Depending on the reliability of the utilities' equipment and delivery system to deliver a steady pressure one can never be bitten in the **** by a properly sized system based on all segments of piping being sized as if there was full load .
remember the INTENT of the code is to minimize the hazards associated with the storage and distribution within the built environment .
That being said , is allowing more potentially hazardous fuel than is needed to operate the equipment at full load as designed to be inside the building keeping in line with the intent and spirit of the code ? I think not but am interested in other's view as well .

There is also a commentary book published by ICC that interprets in plain english what they meant when they wrote it . Pretty cool tool for those who have inspectors who'd like to think they are able to interpret . This interpretation is binding also as it comes right from ICC and if your state has adopted it , it is law .

EBEBRATT-Ed

And yes, the pipe running through the brick wall should be sleeved, no contact with masonary. Most would probably use polypropolyne for this

Tim McElwain

I would get involved here and give some answers but choose to not do so as some who post on this subject does not agree with how I size pipe. I do not want to get into a debate. If the poster wants some help call me at 401-437-0557 or e-mail me at gastc@cox.net and I can answer all your concerns and also help you with some free material on pipe sizing and gas pressures.

Charlie from wmass

Tim do you size using the long hand method?

EBEBRATT-Ed

Either way 3/4" looks to small to me. 1" would be minimum and then is only good for about 25'

j a_2

The good book,being your local code book will have a very simple chart to tell you the minimum size line you need…we in Mass use nfpa54 2012….plus any additional requirements in our state code book….My area has low pressure and dirty gas…house gas filters are commonly installed by the grid around here...

Rich_49

Tim ,

If you were speaking about me , don't fret . There would be no debate . I size using an approved engineering method recognized by the IFGC . If folks can use that method and have a reliable pressure from the utility they may . Or they may choose to size by any approved sizing method in their approved model code .
I know , being who you are and doing what you do would not argue that delivering above the minimum supply pressure while insuring all fixtures have adequate supply when all are calling is improper .

Tim McElwain

Yes I use the longest length method with the chart which has an allowable pressure loss of .3 which will give the largest pipe size. I also sometimes use the branch length method especially if using a homerun. Yes pipe passing through walls must be sleeved. In addition copper can be used if the proper tables for copper are used and the copper is brazed. There is also a restriction with copper as to sulphur content of the gas. I do not want to see any pressure drop from the point of delivery to the farthest appliance with everything running NO PRESSURE LOSS! If you have six inches W.C. at the outlet of the meter (point of delivery) then 65 feet away you should have six inches pressure at the inlet to the gas valve. Proper pipe sizing will typically give you that.

Rich_49

Tim ,


Do you work for a utility ? No debate to follow , just curious . It is an interesting theory though .

ChrisJ

I didn't know copper could be brazed for a gas line.
I thought it had to be flared.

This could come in handy at one point.

Gordy

ChrisJ said:

I didn't know copper could be brazed for a gas line.
I thought it had to be flared.

This could come in handy at one point.

Do you know why it has to be brazed,or flared, and not soldered?

ChrisJ

Gordy said:

ChrisJ said:

I didn't know copper could be brazed for a gas line.
I thought it had to be flared.

This could come in handy at one point.

Do you know why it has to be brazed,or flared, and not soldered?

A guess would be the soft solder gets attacked by something in the gas?

Charlie from wmass

Strength of the joints would be my guess.

ChrisJ

Charlie from wmass said:

Strength of the joints would be my guess.

Have you ever tried to tear apart a soft soldered joint? You'll crack the copper first.

ChrisJ

After seeing this I change my answer.

" they should be made using a brazing alloy with a melting point above 1,000 F. The brazing alloy must contain less than 0.05% phosphorus."

I think it's to keep the solder from melting and letting go if the building is on fire. However, I guess I can't use my Stay-silv 15 rod for it because it contains something like 5% phosphor. Guess you need to use flux and a different rod.

Charlie from wmass

Pulled many soft solder joints apart without breaking pipe or fitting. Especially threaded adapters.

ChrisJ

Charlie from wmass said:

Pulled many soft solder joints apart without breaking pipe or fitting. Especially threaded adapters.

Did you solder those?

Charlie from wmass

No. But the solder fully covered the joint inside.

RobG

Charlie from wmass said:

No. But the solder fully covered the joint inside.

Probably 50/50 solder. I stockpiled a case of it years ago and have used maybe a roll of it so far. I will cheat if I am in a tight, flammable situation.

Tim McElwain

Answer for Rich - I worked for a public utility (gas company) for 28 years 1966 to 1994. For ten of those years I was a service technician. The last eighteen I was the training director and instructor for 106 service techs.

My piping direction is built upon many years of dealing with pressure problems and seeing some caused by poor pressure from the utility and many more due to undersized piping. That was especially the case in the inner city which has only low pressure mains less the 14" W.C. pressure.

Since 1994 when I was downsized out of the utility along with 29 others over 50 making over $50,000 a year I have been all over the country doing training. From 1994 to 1999 I worked for Honeywell traveling all over the country conducting training with their "Source" Program.

In 1999 I opened the Gas Training Institute and have had the opportunity to train many techs since then from all over the country.

Hope that answers the question sorry to be long winded.

Charlie from wmass

You are the final word on Gas in my book Tim.

Steamhead

If Tim doesn't know it, we don't need to. He's the best!

4Johnpipe

Nice resume Tim! That must have been quite a job dealing with 14"WC in the gas mains...That sounds like it kinda sucked. I just had to break the news to a potential customer they could not get a Rinnai when I noticed no regulator on the gas main. They have 7" only.

Tim McElwain

Here in the North East in major cities it is not unusual for the pressure in the street to drop down to less than 6" W.C. pressure and at times as low as 4 inches. Mod/Cons can be a real problem in those kind of conditions. We have a moratorium in Cape Cod as no gas can be put in for now due to lack of pressure and supply due to poor pressure and pipe size.

I am well aware of hybrid systems using 2 and 5 pound pressure to a manifold (homerun) and dropping down from a pounds to inches regulator for feeding inches water column to appliances.

I teach all of the methods which are shown in NFPA 54 and also the International Fuel Gas Code plus CSST applications. It is just that not all are applicable when questions arise here on HeatingHelp you have to know what the inquiring party has for a location because of the differences in pressure provided by local utilities..

4Johnpipe

I hear you...We have a great natural gas supplier in this area of New Jersey NJNG. We can get high pressure almost on request. I am still amazed though how many plumbing contractors do not even test pressure at the meter before adding to an existing gas system nor do they check the CFH of the meter. It causes headaches when a generator gets added then the heat doesn't work when a 500K whole house generator kicks on or a pool heater for that matter. The customer I spoke of above is not in NJNG territory.