Gas Controls & Piping questions & answers.

In this article series we provide descriptions and photographs how to select, install, diagnose or repair leaks or operating problems in fuel gas piping, regulators, or controls used on gas fired appliances or heating equipment, addressing both natural gas and LP gas equipment.

Q&A on Fuel Gas Controls, Valves & Piping

These questions & answers about the selection, installation, troubleshooting & repair of various types of fuel gas controls, gas meters, gas valves, gas piping and gas-fired appliances were posted originally at x - be sure to check out the data given there.

On 2019-02-16 by (mod) - hazards of mercury in gas regulators

Mike

Please see your question and our reply at MERCURY HAZARDS in APPLIANCES & GAS REGULATORS

It'd help me out if you'd try to avoid posting the same query in multiple places, as we have quite a few requests from readers each day.
Thanks.

On 2019-02-16 by Michael Soules

Do older gas pressure regulators leading to an individual gas appliance (gas fireplace, range, etc.) ever contain mercury? I know that older gas regulators leading into a home sometimes contain mercury, and would like to know if the pressure regulators for a single appliance can as well. (The specific situation I'm interested in involves a gas fireplace connected to a very old-looking pressure regulator.)

Thank you for any thoughts!

On 2018-09-26 by (mod) - don't confuse gas pressure with adequate flow rate

It's not the pressure per-se that will be the problem, it's the length of the line and its diameter that could mean that the glow to a distant heating device or burner will be inadequate

. If the installer knew the BTUh rate of the fire pit they would be expected to put in a big-enough line. Usually the appliance manufacturer also gives a table of pipe size vs. lengths for their appliance. That's what I'd check.

On 2018-09-15 by Tj

I live in a neighborhood with normal 4oz nat gas supply to the house. ie: stove, heater, 2 HW tanks, gas fireplace.

We just finished a pool so the gas co is upgrading us to 2LB pressure due to the 400k pool heater. Pool company installed a small regulator next to the heater, so all seems ok. HERE IS MY ISSUE --- We also are building a nat gas firepit in the backyard.

With 2lb pressure at the meter, it is then 120 ft to the pit going down side of house and around pool. They installed the yellow plastic line in 1 1/4 size.

I did not pay them to build the pit and finish it, I am. I only paid them to stub up the correct service.

They ran the 1 1/4 line all the way to the stub up with no regulator. (remember, from a SEPERATE line coming from 2lb service). I'm sure I need a regulator and usually see them at the appliance (firepit) end. Firepit is 180k BTU, require 4oz.

The pool co said to just add the regulator where the line comes off the meter.

Can I do that, and if so, how do I measure if I will have 4oz and 180btu at the pit 120 ft down the yard?

On 2017-11-23 by (mod) - how we can select pipe size for distribition in a building?

Farhan

Please see GAS PIPING SIZE & MATERIAL at https://inspectapedia.com/plumbing/Gas_Pipe_Specifications.php

On 2017-11-23 by Farhan

how we can select pipe size for distribition in an building

On 2017-08-19 by (mod) - we think we smell a gas leak

Clary,

The mercaptan added to LNG or LPG to help people notice when there is a gas leak can sometimes be mistaken for a sulphur odor but actually the two are different and distinctive.

If the odor is stronger near your LPG tank I'd be suspicious - sniffing or soap testing or tests using a combustible gas analyzer can help sort that out.

See GAS LEAK DETECTION, LP / NG https://inspectapedia.com/plumbing/Gas_Leak_Detection.php

Watch out: And if you think there is a gas leak,

- leave the building

- do not operate anything that can cause spark - like light switches or telephones

- call for emergency services from a safe, distant location

- if you can safely do so, TURN OFF the gas supply from outside.

But there are different sources of sulphur odors. See SULPHUR & SEWER GAS SMELL SOURCES https://inspectapedia.com/odor_diagnosis/Sulphur_Odor_Sources.php

On 2017-08-19 by clary

my house smells very strongly of sulphur. we have lpg tank outside. how can i discover if it is that?

On 2015-09-07 by (mod) - gas switching valve for backup generator

Greg:

There are probably commercial grade automated controls and valves for switching between fuels as certainly power plants and industries do so.

But WATCH OUT: one can never simply switch over from LP to natural gas without making other changes in the equipment: the two fuels operate at different pressures, require different regulators, and they require different burner orifices. Simply changing fuel alone is not going to work and would be dangerous.

In earthquake country I'd focus first on security of the systems (mounting, gas line protection) and on autmoagic shut-offs on my fuel line so as to avoid feeding fuel to the fires that often accompany an earthquake.

I would by no means consider it safe to "turn on" a gas fuel automatically during or right after an earthquake. For example, the municipal gas supply or NG may have been deliberately shut off for safety.

On 2015-09-07 by Greg

I have a backup generator at my home. It has a manual valve inside the cabinet to switch between NG and LP.

Is there some kind of switching valve that would do this automatically if the NG pressure drops to zero? We have expensive medicine for a sick child that needs to be kept refrigerated so it would be great if we had propane tanks that will switch in automatically if there is no natural gas pressure. We live in California where this is always a possibility because of earthquakes.

On 2011-08-15 by (mod) - regulations for connecting a gas bottle to a residential stove?

Brian there are more details for safe gas piping and connections than are appropriate to outline in a simple Q&A format here.

Start with the installation manual for your gas stove.

If you don't have the manual for your stove or gas range

see GAS COOKTOP RANGE & OVEN REPAIR & MANUALS

You'll want to see National Fuel Gas COde NFPA 54, or ANSI Z223.1, for example regulations and piping details.

Be sure to also see the gas piping procedures outlined at GAS PIPING, VALVES, CONTROLS - home

Watch out: You'll see that the pipe diameter depends in part on the length of pipe run and also on the number of appliances that might be served. In very general terms you'll need to run solid iron pipe where piping passes hidden through building cavities like walls and ceilings; flexible copper is often used in exposed locations;

Because there are fire, explosion, and life safety concerns involved, if you are not experienced in and expert in gas piping I'd be careful about a DIY project, and in any case I'd be sure to obtain a proper safety inspection by your local plumbing code officials. You may also find that your gas company won't hook up nor turn on a gas bottle (LP Gas Tank) without an inspection of the gas piping, control valves, and equipment.

On 2011-08-15 by Brian Edmund

What are the regulations for connecting a gas bottle to a residential stove? Size of pipes etc.

Question: inspection schedule for gas piping

(Dec 4, 2012) Sergi Solt said:

I live in a 43 years old building, with 2 big tanks Gas LP.
How many years last the inside lines of the building, before needed inspection or replacement?
tank you.
sersol@prodigy.net.mx

Reply:

Sergi, I've not see a gas piping inspection schedule based on age; But certainly a check for leaks as well as for identity of piping material and its condition would be smart given the building age.

About the question: When does an LP gas tank need replacement, LP Tank replacement rules vary; some tanks have a date stamped into the steel; take a look for that data and then ask your gas supplier about local tank regulations.

And of course it's very relevant to state whether this tank is above ground or buried - buried tanks subject to corrosion; above ground tanks subject to mechanical damage;

Finally, your gas company should also inspect the regulator condition.

Question:

(Dec 7, 2012) ivan said:

How can you tell if a boiler is hooked up for propane or natural gas?

Reply:

Ivan, a simple approach for an existing gas boiler is to follow the gas piping to its source - an LP tank or piped in natural gas through a gas meter.

More complex and detailed: the actual burner parts and adjustments need to be swapped or adjusted when changing between natural gas fuel and LP gas fuel for any appliance (not all appliances are convertable). These are discussed in the article above.

...

Continue reading  at GAS PIPING, VALVES, CONTROLS - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Gas Piping & Regulator Articles

• GAS PIPING, VALVES, CONTROLS - home
• FLARE FITTINGS
• FLEXIBLE GAS CONNECTOR INSTALL
• GAS PIPING CLOG REPAIR
• GAS PIPING CLEARANCES, CODES & DEFECTS
• GAS PIPING, FLEXIBLE CSST
• GAS PIPING SIZE & MATERIAL
• GAS LEAK DETECTION, LP / NG
• GAS PRESSURES LP vs NATURAL GAS
• GAS REGULATOR ADJUSTMENT PROCEDURE
• GAS REGULATOR CONVERSION NG-LP
• GAS REGULATORS & APPLIANCE / HEATER CONTROLS

Suggested citation for this web page

GAS PIPING, VALVES, CONTROLS FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to GAS APPLIANCES, PIPING, CONTROLS

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