Clogged gas line or a bigger problem

[BCBandit]

Sorry up front that this is long. I want to provide as much information as possible to get your feedback.

Short version: I have gas to my furnace and stove/oven, but none to my water heater.

Long version: Live in Central Texas, so went through the frozen rolling blackouts and 2 days of no water. At no time did I lose gas. Once water/power returned, flushed water heater due to brown hot water. No problem relighting 40 gal water heater. All gas systems were working fine, furnace, stove, pool heater, water heater. For last 3 weeks no problems until this Saturday morning. Water flowing from several placed on the water heater (in the garage). Shut off the water and gas then called for help.

New heater installed and then we discovered there was no gas to the heater. Furnace and stove still work, with no problems and no noticeable loss of gas (i.e. burners look normal at specific settings). I can not confirm if the pool heater works, as it doesn’t ignite, but I’m not getting any lights from it (so it may be a different issue). So for sure, no gas to the water heater. The guy that installed the new heater (Plumber #1) sniffed checked the line from valve to heater…no gas detected. Directly from the valve, ensured it was open visually…no gas smell. Removed the valve…no gas smell. Verified the gas to the house was on…yes. Even sniffed checked the hose to the furnace…gas there.

Plumer #1 called in plumber #2… who repeats actions of plumber 1.. said it is blocked and we have to bust walls and cut the lines. (imagine my wife’s reaction to busting walls).

Called another organization and out comes plumber #3. Repeat of #1 & 2. Said he needed to do a pressure test. Plumber #3 calls experienced plumber #4 who suggests blowing the gas lines with nitrogen to see if it clears a block. Plumber #3 calls supervisor plumber #5 who is thinking cut the line to find the block. (It was after hours and plumber #3 was not comfortable doing that at the time of the night).

A little about the house…built 2014 single story. Gas meter is tagged 5psi. Pipe enter the house, 90 degree straight up to the rafters. Looks to be a metal 2” line, but not sure of the size. I can follow to a small T connections that runs a small flex to the furnace. Pipe runs straight approx. 6’ to another T connection. The T stem appears to go to the kitchen. Pipe continues straight another 6’ to a T connection. This T stem is the same diameter and looks to be for the pool heater (gas line for pool run was part of the house construction, not an add on). At this point, as the main gas line continues straight, it steps down in size from the 2” to maybe 1” or ¾”. This runs straight about 6’, then 90 degree bend down and runs to the just above the foundation. 90 degree to parallel the foundation for approx. 3’, then 90 degree right for 1’ then 90 degree up for 2’ then it comes out the wall for the water heater. (it avoids the fixed stairs to the attic). So the water heater is at the end of the line.

Any idea what happened?
I’m considering having the gas lines blown out before starting to open walls and cut pipes. Do I need to worry about them cutting into the pipes (thinking structural integrity)

I’m open to suggestions or opinions. Thanks for taking the time to read it all.

 

[The Cobbler]

the pipe just can't "block up" like that . I'm wondering if somehow water has collected ina low point and blocking the flow .
I like the idea of blowing nitrogen ( or even air) through the pipes . just be sure to close off all valves to all fixtures so you don't overpressure them.
By cutting intot he pipes won't hurt the integrity of them, but that should be able to be done without cutting the pipes

 

[BD1]

Depending on exposed piping, I would start to remove gas piping from water heater and work towards main.
Have pipe plug and cap ready if gas starts to escape .


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[samss]

"This runs straight about 6’, then 90 degree bend down and runs to the just above the foundation. 90 degree to parallel the foundation for approx. 3’, then 90 degree right for 1’ then 90 degree up for 2’ then it comes out the wall for the water heater."
Plumbers chime in here....would this be a potential trap if there isn't a drip leg before the up turn?

 

[BD1]

This doesn't make sense. The gas piping system is a closed system so I cannot see how anything could get into pipe .
If you don't want to start removing existing piping, consider plugging existing at water heater. Then tie in at existing gas main where gas is present and run new to water heater.
You gotta tell us what happened.

 

[BCBandit]

Your thoughts start to make sense. Plumber #2 first mentioned water in the line, and I had the same reaction of...how does water get in a closed system.
The theory is when the water heater failed (water coming out the top and the electronics at the bottom), water could have gotten into the combustion chamber with enough pressure to push the gas back to that low spot.

Samss mention of a drip leg (assume that is like an appendix for a gas line) would have caught any water. There is nothing like that installed.

I'll provide updates..Thanks

 

[BD1]

Your thoughts start to make sense. Plumber #2 first mentioned water in the line, and I had the same reaction of...how does water get in a closed system.
The theory is when the water heater failed (water coming out the top and the electronics at the bottom), water could have gotten into the combustion chamber with enough pressure to push the gas back to that low spot.

Samss mention of a drip leg (assume that is like an appendix for a gas line) would have caught any water. There is nothing like that installed.

I'll provide updates..Thanks

The water heater gas valve should be normally closed when satisfied. If water did fill bottom of heater where burner is, noway could it backup into gas piping.
One pound of pressure will raise water 2.31 feet in a column. Water would have to go through burner, up the tubing , pass through the gas valve, and into piping. There's no pressure to do this because water was leaking out .


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[Wrench97]

What kind of pipe do have?

 

[rlitman]

The water heater gas valve should be normally closed when satisfied. If water did fill bottom of heater where burner is, noway could it backup into gas piping.
One pound of pressure will raise water 2.31 feet in a column. Water would have to go through burner, up the tubing , pass through the gas valve, and into piping. There's no pressure to do this because water was leaking out .


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The burner would have to be submerged over a foot under water. Thinking this through, a stream of water perfectly directed at the burner could meet this pressure, but would leak out the venturi. I'm not sure if you could even aim a stream of water directly at the orifice.

Is it possible that there's water in your gas line? Sure. But I doubt it got there via the water heater.

Now, about blowing the lines out and pressure testing. Um, not the way it was described!

Appliance gas valves (not the shutoff valve, but the pilot valve), are not designed to handle high pressure. Applying pressure into your system with appliances on it risks doing major damage. The thought of blowing air back into the gas system also sounds awful.

If it were my house, I'd do the following:
1) Search everywhere for a valve you forgot was turned off.
2) Barring some errant valve, I would close the shutoffs on every appliance of mine, and physically disconnect every appliance from the gas system. Then shut the main, and disconnect my gas pipes at the meter. Finally, blow air in from that end to pressure test and blow out any water. If there is water, it's going to come out rusty and loud. Figure out a way to contain the mess (pipe it outside with a hose or something).

 

[acmikee]

your going to need to pressurize the line with air. shut off gas at meter remove all valves and cap the lines leaving the one open to the water heater add air at the meter and see what comes out....after you finally get air repeat the process for all the other appliances to insure all lines are clear reinstall valves pressurize and test for leaks and purge the gas lines reconnect everything and relite all appliances

 

[karoc]

Be careful,to much air you bust all diagrams in your regulators

 

[samss]

Drip legs are for more than just water/moisture. The inside surface of iron pipe can flake off. Pipe is not sealed when shipped and stored. Bugs and their nests are not always noticed when pipe is cut, threaded and installed. I've found more than a few crickets that made it all the way to a pressure regulator.
acmikee has the solution.

 

[spudley]

Five plumbers and still no solution? Any of these guys have a license? The first guy in there should've followed the order acmikee described.

 

[karoc]

Another thing to consider is most plumbers can run pipe and fix drains but when it comes to testing gas pressure to see if you have what you should at gas meter then at each appliance you should be calling HVAC company and not plumbing company. I use to carry one of these to check gas pressure.

 

[BCBandit]

Short version...Water in the line

Long version:
The company that used plumbers #3-#5 sent out plumber #6 and a sidekick.
He obviously did not talk to #3-#5 so I got to explain everything once again. Bit of head scratching and verification that the pool heater had gas, he did the smart thing, called the boss for help, since he didn't have the equipment to blow out the lines.
Believe it or not, Plumber #5 shows up with plumber #7 (sidekick). 10 minutes of discussion and off to work they went.
Shut off gas, cut the line past the stepdown for the heater, installed a valve on the live end had #7 shoot nitrogen from the heater side and then we heard shouting and asking for a bucket. Blew out about 3/4 cup of dirty water. Blew it from the opposite end and another 1/2 cups came out (I measured).

High fives all around until they discovered they don't have all the parts and tools to put it back together. Calls made for parts, so they took a look at the water heater... more head scratching at a new inflow valve installed backwards (plumber #1), a 90 degree cast iron connected to the expansion tank copper (might have been bronze) line for the expansion tank (part of the original install) and no balloon in the original expansion tank. They switched those out and the gas parts arrive.

Who brings the parts..plumber #4!.

So everything put back together and everything works!
And for those asking.... using the term plumber for guy #1 is incorrect... should be "a guy". Lesson learned..use a licensed plumber! Then again it was a 3 week wait to get someone out and my wife did the calling.

Thanks for your inputs... I knew what to ask and what to look for.

 

[HoosierBuddy]

As soon as I read your post I knew you had water in the line.

I'm still not clear how it got in there.

What I've seen (many many times) is customers how have run a line to an outbuilding etc that is underground and it gets full of water and won't flow gas. In every one of those cases, the water got in because of hole(s) in the pipe. So the pipe had to be replaced or the leak fixed as part of the repair.

To be clear, you never see this on gas lines operated at higher pressures...it only occurs on buried lines where the ground water pressure is higher than the gas pressure.

Oh...and I once saw it when a hotel maintenance person connected a water line directly to their gas line. I'm still not sure what he was thinking, but he managed to fill every bit of gas line the building with water in short order. That shut down the kitchen pretty quick.

Phil

 

[Innovate1]

You say "plumber" 1 was not a plumber but just a guy. Seems like that could be applied to a few of the others as well. Shouldn't take 7 plumbers to figure this out. I have only done a little with gas lines and not a plumber and hadn't thought about how water could plug a line due to low gas pressure but I would expect a plumber to know. Maybe not the first guy they send out but who he calls for more difficult stuff. Just goes to show that having a license (or appropriate credentials depending on the line of work) doesn't always mean you are skilled or even competent at your craft. Trouble is they often say they are experienced and great so you can't always rely on that. Sometimes it's easier to just do it myself - if it's not too big of job and I have the needed equipment.

 

[Milton Shaw]

I would do a pressure leak down test on that line to make sure you don't have a leak that is now leaking gas underground or into your house. Cap both ends of the line and use air pressure to test it and give it an hour or two or overnight to leak down to make sure it is leak tight. From what you have said, I don't think you have had a plumber that knows gas to your house yet. I had leak tested my pipe with 120 PSI before the gas inspector got here, he checked it with less than 10 lbs, so I was Ok.