Purging Air from Gas Line
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Purging Air from Gas Line Author: overhaulin (OH) I just installed a radiant heat boiler in my garage and was wondering what the best method is for filling up the line and purging any air in the system?
Thanks in advance for any assistance!
Re: Purging Air from Gas Line Author: packy (MA)
so much depends on what you installed to purge the air from the lines?
if you used the pre-made manifolds then they are set up to purge from the return side.
post a picture of your set up so someone can be more specific as to what to do..
Re: Purging Air from Gas Line Author: overhaulin (OH)
I am new on the site and I am not sure how or if I have privileges yet to post a photo.
The set up is basically a gas line coming into the garage and entering a boiler model; Dunkirk VLT-100
Re: Purging Air from Gas Line Author: overhaulin (OH)
[postimg.org]
I think this might work.
Edited 1 times.
Re: Purging Air from Gas Line Author: packy (MA)
i thought you wanted to purge water from the circuits >???
if you want to get the air out of the gas pipe. i just crack the union and let some air out until i get a strong smell of gas. then tighten the union and fire the unit.
this is kinda dangerous for an DIY so be very careful.
there is no method like pulling a vacuum on an air conditioning system.
Thanks Author: overhaulin (OH)
Got it... Thanks Packy!
Edited 1 times.
Re: Purging Air from Gas Line Author: PlumberLoren (CA)
Packy is right again. He is telling you to wait for the smell of gas to go away prior to lighting the pilot...give it a few minutes if you are in a confined area. If outside the wind will clear the gas so it is safe to light. But like he says...Be careful with gas. I burned my hand, arm and singed my eyebrows when I was a young Plumber by not adhering to Packy's advice.
Re: Purging Air from Gas Line Author: hj (AZ)
This is a "gas line", not radiant heating tubing. How WE would purge it is probably NOT how you should do it. Purging it through the pilot burner is the "safe way" even though it can be time consuming. Any other way, if done incorrectly can cause an explosion.
Re: Purging Air from Gas Line Author: hj (AZ)
ALL of that is why I said I 'Would not" give him a recommendation other than the pilot light.
Re: Purging Air from Gas Line Author: packy (MA)
the picture of the job looks pretty darn good to me. i would say this person has very good set of skills and is capable of dealing with the dangers of some gas in the air.
yes, the procedure of letting some gas escape has a certain danger involved but once made aware of this danger the decision is up to the installer.
if the person wants to crack the union, let the gas leak out for a couple of minutes and then decide to light up a cigarette ??? that takes a certain kind of stupid the neither you nor i can reason with..
Re: Purging Air from Gas Line Author: hj (AZ)
An apprentice was working at a new police station near here. After installing the unit heaters, he did the "break the union" and purge the gas. He then proceeded to almost burn the building down.
Re: Purging Air from Gas Line Author: PlumberLoren (CA)
Yes do understand how dangerous natural gas or butane is. One bad decision can cost lives.
Re: Purging Air from Gas Line Author: bernabeu (SC)
The yellow 'flex supply' is NOT installed properly.
The valve should be on the bottom steel pipe before/upstream of the flex in order to isolate same for service / replacement,
and
BOTH lower unions on the steel are superfluous.
Minimun fittings is good/best practice.
Neat, close to proper, but no prize.
PURGE THROUGH THE PILOT ~ THERE IS NO RUSH
==============================================
"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
Edited 2 times.
Re: Purging Air from Gas Line Author: packy (MA)
bernabeu, don't be so quick to criticize..
you have no argument here with this installer.
the yellow flex tube you refer to is a factory installed part.
the gas pipe and union below is not superfluous. it is exactly the way it should be as all field piping is done OUTSIDE the boiler.
please familiarize yourself with the way these type boilers are installed before being so critical.
Re: Purging Air from Gas Line Author: bernabeu (SC)
packy,
then the OP must have REMOVED the flex and installed the valve on the equipment side INSTEAD of the supply side
proper sequence:
metal supply pipe -> gas valve -> flex connector -> appliance/boiler
gas flow would be left to right / valve -> flex -> boiler
?which end gets the valve?
the unions mentioned are extraneous
the unions were used in order to pipe with nipples instead of cut pieces
==============================================
"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
Re: Purging Air from Gas Line Author: packy (MA)
geesh... here is a dunkirk boiler picture..
note the factory installed gas valve.
Re: Purging Air from Gas Line Author: bernabeu (SC)
I can not argue with a factory picture.
I guess I am simply out of date and probably out of touch with the modern insanity.
Personally, I would install an additional valve AWAY from the actual boiler 'workings'.
packy,
why would the factory install a flex between two fixed points INSIDE the control box ?
==============================================
"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
Edited 1 times.
Re: Purging Air from Gas Line Author: packy (MA)
i'm sure there is a gas cock that is just out of view in the installers picture.
installation instructions call for one.
i didn't notice the 2 unions. that is against my code.
i don't see anything wrong with combining 2 nipples to make one long one.
i was taught that when you have a real long measure (like 16 feet 3 3/4 )that you don't want to make a mistake on, cut and thread a piece a little shy like 16 feet long and make up the difference with a nipple and coupling.
as for why dunkirk boiler company uses a gas flex inside ???? probably has to do with $$$$
Re: Purging Air from Gas Line Author: bernabeu (SC)
I hope I live long enough to learn even more.
Thanx.
==============================================
"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
Re: Purging Air from Gas Line Author: steve_g (CA)
I must be old too. I would've done it same as bernabeu says.
Re: Purging Air from Gas Line Author: hj (AZ)
That valve is the same as the old control valve with the pilot cock, inside the jacket, and it is NOT the main EXTERNAL shutoff valve which should be ahead of the flexible connector and would be used to turn off the gas in an emergency.
Edited 1 times.
Re: Purging Air from Gas Line Author: bernabeu (SC)
D'OH
correct again
==============================================
"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
Re: Purging Air from Gas Line Author: bernabeu (SC)
[www.dunkirk.com]
see page 26
external shut off valve REQUIRED immediately before 'cabinet'
I am NOT a dinosaur
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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
Re: Purging Air from Gas Line Author: packy (MA)
from my post above..
quote..."i'm sure there is a gas cock that is just out of view in the installers picture.
installation instructions call for one. "..
Re: Purging Air from Gas Line Author: bernabeu (SC)
perhaps - misplaced
==============================================
"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
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When preparing natural gas pipes, regulators, appliances, equipment and apparatus for service, or returning them to service, do not purge their contents into a confined space or where natural gas can accumulate.
Any purging of natural gas, or purging of air or other contents with natural gas, should only be done in a well-ventilated area or by safely venting the contents into the outside atmosphere where there are no people, animals, structures or sources of ignition present.
Before purging, make sure you identify and eliminate all sources of ignition where natural gas may be vented, recognizing that natural gas is lighter than air and will rise. Sources of ignition include:
- Standing pilots
- Open flames
- Cigarettes and other smoking products
- Electric light switches and appliances
- Motorized equipment and vehicles
- Temperatures above 1,100 degrees Fahrenheit
- Anything that may cause a spark
Use natural gas detection equipment during all natural gas release operations to prevent natural gas from accumulating and creating a combustible or hazardous atmosphere. DO NOT rely on your sense of smell alone to be alerted the presence of natural gas.
The National Fuel Gas Code, the California Plumbing and Mechanical Codes, applicable Building and Safety Codes, and local Departments of Building and Safety should be consulted for more information and before any natural gas release operations begin. Also see the Chemical Safety Board's Safety Bulletin.* When installing natural gas appliances and/or equipment, the manufacturer's instruction manual should be followed in conjunction with the local code authority.
DO NOT RELEASE THE CONTENTS OF A NATURAL GAS LINE INTO A CONFINED SPACE. ANY RELEASE OF NATURAL GAS PRESENTS THE POTENTIAL FOR EXPLOSION AND FIRE THAT COULD RESULT IN SERIOUS INJURY AND DEATH. PURGING AND OTHER RELEASES OF NATURAL GAS REQUIRE EXTREME CAUTION AND SHOULD ONLY BE PERFORMED BY QUALIFIED NATURAL GAS PROFESSIONALS.
Learn how to recognize and respond to a natural gas leak.