Gas pressure....


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Old 05-02-04, 08:59 PM
Starscream
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Gas pressure....

I am in need of information on what exactly the pressure is as far as gas coming to the house, info on metering, and basically any info on any change that needs to be made as far as fittings when installing a furnace.

The big thing is gas pressure. What is it normally? Any info/website will be appreciated. Thanks in advance!
 
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Old 05-02-04, 11:20 PM
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Pressure is about 1/2 PSI.

What metering question?? The meter belongs to the gas company. Don't mess with it!
 
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Old 05-03-04, 05:16 AM
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Hello: Starscream

Lefty is very correct. Contact the gas utility supplier. Metering and pressure equipment belongs to and is maintained by the supplier. Customes should not attempt any services to that equipment. Phone number is on the bill.

Coneecting piping for furnace installation depends upon the job being a totally new installation or a replacement of existing furnace. Not mentioned in your question. Kindly use the reply button to add that information. Doing so allows use to better provide helpful advice.

Piping should be equal to the existing pipe sizing for furnace replacement. For installation of a totally new furnace, pipe sizing is based upon the BTU rating and length of distance to furnace from the main house piping.

Metering? If there is already gas supplied to the house for other gas appliances, the metering is not a concern. Supply volume and pressure is already correct. There is no website or public viewable information pertaining to gas volume and or pressure and or metering. Contact the utility.

All gas appliances have there own built in gas regulator which controls the volume and pressure. All that is needed for installation is connecting to an existing gas supply. All connections and installations must meet local codes.
 
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Old 05-03-04, 06:13 AM
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Its all in where you are and what you have . The gas company set the pressure. For nat gas lots of times it around 4" or 5" W/C ,LP gas about 11"W/C. Like sharp said gas line size work on the BTU of the unit. dont forget to add 5' to the pipe run for any 90o L in the gas pipe on NAt gas.

ED
 
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Old 05-03-04, 05:18 PM
Starscream
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Thanks for the replies. My question is pertaining to a first install of furnace. Not just switching them out.

I am looking for the route and pressure changes the gas will make going from the pipe in the ground to the furnace. Pressure coming out of the ground and any changes it makes. Does it change at the gas companies meter? If so from what to what? Or does the control valve on the furnace regulate the pressure? Is there a device that can be used for this?

I'm really in need of some reference or explaination about understanding gas pressure (water column, etc) a little better as well. Thanks and cheers!
 
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Old 05-03-04, 06:12 PM
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Hello: Starscream
Gas pressure out of the meter for natural gas is 7 to 10 inches of water column. That is all that is required for any house, building and or structure you will ever own or work on or in. That is standard gas pressure.

Gas company sets this pressure and it does not change enough for any concern on your part. Nor should it be of any concern. The line you will run to the new furnace or any line tapped into that is already there supplying gas to another appliance(s) does not need any changes made to the existing pressure.

Water column pressure is than reduced from 7 to 10 inches WC to 3.5 to 4.0 inches of water column by the appliances own equipped regulator. Installer of the heated, yourself or a contractor, etc, simply connects appliance to the supply line.

Whether the line is newly installed or tapped into another gas line, existing gas pressure is sufficient. NO adjustments need to be made to any gas pressure.

Any changes will cause problems and I have seen them all. Best left as is.
All above pertains to natural gas. Propane not likely to be any different.

To answer questions asked:
Or does the control valve on the furnace regulate the pressure?
Yes. Control valve on furnace will deal with the pressure. Not any concern needed. Just install furnace per mfg instructions and codes.

I'm really in need of some reference or explaination about understanding gas pressure (water column, etc) a little better as well.
Gas pressure is best left as is. Detailed explaination above.
There is no customer info on gas pressure and none is needed.
Natural gas supplier has already preset gas pressure.
Best left as is. Gas companies do not want customers to attempt any changes to their equipment. Have questions? Call the utility.

Summations:
Run any new gas line as needed.
Be sure newly installed pipe is sized correctly to the furnace load.
Be sure newly installed pipe does not leak.
Line should be leak tested before final connection is made to supply pipe and at the furnace connection end. Entire run needs to be tested according to local city codes and verified leak free. Inspection office issues stamp of approval on certificate of compliance.
Install the furnace to line with a shut off valve installed on the end of the newly installed pipe.
Be sure all piping and installation meets all local codes.
Usual pipe size for furnaces is 1 inch diameter. In some cases 1 & 1/4 inch.
BTU rating and distances determine pipe size. (NOT pressure!)
 
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Old 05-04-04, 11:05 AM
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Starscream Just what gas do you have Nat. Mfg. or LP.
The gas company there should be able to tell you what you need.

ED
 
 

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