capacity of natural gas line


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Old 05-01-11, 04:24 PM
J
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capacity of natural gas line

The gas meter outlet is 1-1/4". One side of a 'T' branches to 3/4" 50 ft. supply to gas furnace (122k BTU). The other side of the 1-1/4" T is blanked off (previously used for swimming pool heater). I don't know how much pressure is on the outlet of the regulator, it's a Rockwell 107 and might be about 45 yrs old.

When my kitchen was remodeled last year, I bought a large 6 burner gas stove (102k btu). The sub-contracted plumber added a 3/4" 'T' close to where the 3/4" heater supply pipe originates and ran a new 3/4" 50 ft supply for the stove.

meter --> 1.25" T --> one side reduced to 3/4" --> 3/4" T --> furnace line & stove line.

So both the furnace and stove supply lines take their gas supply from the same short 3/4" nipple off of the 1-1/4" 'T' at the meter. It seems to me that this may be too much load for 2 high demand appliances and that each of these 3/4" supply lines should run separately from the 1-1/4" 'T' rather than from a 3/4" T. Individually, each line is sufficient according to a table I found on the web. But since they both originate from the same 3/4" nipple off of the 1-1/4" T I'm wondering if this design is under sized.

Should I have the lines redone so that they each branch off from the 1-1/4" outlet?

Or because the supply lines for the 2 appliances branch off only a short distance beyond the 1-1/4" line is the design sufficient? I don't notice any problem in the use of the appliances but I also don't know how to determine if the supply is adequate or not.

thanks, Jon
 
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Old 05-01-11, 05:10 PM
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As far as I know, what you see is good. Nothing is smaller than 3/4.
 
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Old 05-01-11, 06:01 PM
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How far is the total developed length of the farthest appliance?

Furnace or stove?

Example if the stove is the furthest how many ft of 3/4"?

The 3/4" by itself can only supply 151,000 BTU @ 50ft. Now a appliance was added to it.

This is based on .60 specific gravity gas, .5 psi or less, and a .5 inch water column pressure drop.

Most likely you need to change the 3/4 to 1"


Mike NJ.
 
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Old 05-01-11, 10:00 PM
J
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Lawrosa:

Your questions are the crux of my query.

Each appliance is at the end of s separate 3/4" run of 50 ft (give or take a few feet).

My concern is that they are both fed from a 3/4" 'T' off of a 1-1/4" line and in my mind that reduces the flow to both appliances. Since both appliances are high volume consumers I am afraid I'm starving them. I'm trying to confirm if my concern is correct.

Jon
 
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Old 05-02-11, 07:15 AM
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My concern is that they are both fed from a 3/4" 'T' off of a 1-1/4" line
Is this tee right off the gas meter? Or is there so many ft of 1 1/4 that enters the home?

If you measure from the meter outlet both appiances are 50 FT?

Mike NJ
 
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Old 05-02-11, 08:55 AM
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The T is right off the meter. Only 3/4" pipe enters the home. The total run of each of the pipes is 50 ft. They were not installed at the same time. When I had a new stove installed (108k BTU) the contractor ran a new line to the stove. The other line goes to the furnace (122k BTU). Both of these lines are 3/4 and start within a few inches of the meter.

jon
 
 

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