Gas meter problems

ChrisL

I've got a 1,260,000 boiler and 199,00 water heater in an apartment building I own. I am having problems after installing a new high eff water heater of the same capacity as old. It ends up the gas pressure drops down from 6" to 2.5" when the boiler is on. The utility swapped in a larger meter (from 800 to 1000cfh) but the problem remains. So, it ends up the piping from the regulator outside to meter inside is only 1"!

I am asking them to change the piping up to 2 1/2" to the meter. My question is, all these years of running, does the meter accurately measure the gas when the gas running through it has dropped in pressure that much?

Thanks,
Chris

EBEBRATT-Ed

I don't believe the pressure drop in the piping will affect the meter reading.

How did this ever pass inspection with a gas line as badly undersized as that????

No permits??

Chances are the new high efficiency water heater is less tolerant of low gas pressure and gas pressure fluctuations.

ChrisL

Yes exactly. The new water heater (actually a tankless with a storage tank) flutters out on high fire, as there just isn't enough supply.

The 1" pipe is the utility piping. The workers are completely unaware of pipe sizing. I had to argue for a long time it was undersized, and they disagreed. So, now I have to make sure they install the right size......

Zman

If this is low pressure gas, it sounds like your meter is still significantly undersized. At 1,000 btu/cf for nat gas, you would need a 1,500 cfh meter.

Zman

This is a nice little calculator http://www.engineeringtoolbox.com/natural-gas-pipe-calculator-d_1042.html

Plugging in the quick numbers, it looks like it would only take 8' equivalent of 1"pipe to account for the 3" wc you are missing. That is not accounting for what your undersized meter is losing.

BobC

The gas company may have pressure problems on the street.

Bob

EBEBRATT-Ed

1" pipe is way too small for this load. @Zman is correct. If your #s are right the meter is still undersized

rick in Alaska

Is this a high pressure system with pressure reducers at each appliance? That would make more sense with a 1" pipe.
Rick

ChrisL

Thanks for the info. I've wasted a lot of time trying to get this resolved. The gas utility is staffed with people of very limited knowledge and abilities, and so you have to allow them to do their thing, and have it fail, before they will move it up the chain of command. I filled out a form of the load, and they recommend a 1000cfh meter. They install it with a 1" low pressure line coming from the reg, and then can't figure out why it doesn't work. Next step, they make two incoming lines...one for building, other for apartments. They now come from regulator with 1 1/4" line. So now I am at 4" w.c under load. An improvement, but still not enough.

Here is my question: They now want to go with 2 psi service. I do not want or need this, as my piping is sized correctly. It would resolve the undersizing on their piping though. So am I responsible for paying for this? All I am asking is for 6'w.c at the meter outlet for its rated load capacity.

Thanks,

Chris Lober

EBEBRATT-Ed

Unfortunately the utilities pretty much get things done the way they want and usually not much can be done about it

Tim McElwain

What is the gas pressure at the inlet of each piece of equipment with the equipment off and nothing running? Is the gas in the street low or high pressure? With the equipment running individually then all together what is the outlet pressure after the gas valves? The 800 to 1,000 cfh is too small a meter. You need a rotary meter to be able to handle the full load.

Tim McElwain

I would contact the engineering department at the utility.

ChrisL

Inlet pressure at equipment is .5" less than at meter.

Inlet pressure at equipment idle: 6"w.c. Running: 4"w.c. Service is high pressure to a regulator outside. It then goes approximately 12' to the meter.

With the current setup at 4" w.c. while running, the tankless appears to be running ok now, but its below the install requirements.

I am working my way up to the engineering department....I'm sure the old timers would have gotten this right from the very beginning!

Abracadabra

Most state utility boards require the gas utility to provide 6" at the outlet of the meter. If you aren't getting 6" at the outlet of the meter with everything running.. video it, send it to engineering dept and you should quickly have a solution installed. I had to go thru the same hassle for a customer. Customer was blaming my install..

ChrisJ

Yeah,
Sounds strange.

We're setting up my friends house for 2 PSIG gas service because it was originally LPG and some of the piping is too small. He decided to buy the regulators rather than redo the piping.

But to do it because the gas co can't supply the right pressure at the meter is silly.

EBEBRATT-Ed

I will bet this job is "downtown" in an old city!!

Years ago I was pressuring the gas utility for more pressure on a job. Basically they admitted that 6" was all I was going to get.

I persisted they told me if they did they would "give away a lot of gas"

I didn't understand until he explained that there old 100 year old cast iron piping in the streets leaked more when they turned the pressure up.

I was told by a rep that sells gas boosters that Boston still has "wooden gas piping" still in use.

Don't know if its true

A lot of the old cities the infrastructure is shot

ChrisJ

EBEBRATT-Ed said:

I will bet this job is "downtown" in an old city!!

Years ago I was pressuring the gas utility for more pressure on a job. Basically they admitted that 6" was all I was going to get.

I persisted they told me if they did they would "give away a lot of gas"

I didn't understand until he explained that there old 100 year old cast iron piping in the streets leaked more when they turned the pressure up.

I was told by a rep that sells gas boosters that Boston still has "wooden gas piping" still in use.

Don't know if its true

A lot of the old cities the infrastructure is shot

I doubt it,
How could they offer 2 PSI to him then unless there's a high pressure regulator at the meter?

JUGHNE

Could the gas co move the regulator up to the meter, that would eliminate 12' of low pressure pipe......or is the meter inside the building and the reg not allowed next to it?

Zman

JUGHNE said:

Could the gas co move the regulator up to the meter, that would eliminate 12' of low pressure pipe......or is the meter inside the building and the reg not allowed next to it?

That is a really good idea. If they put it on the other side of the meter, they may not have to change the meter, just recalibrate.

bob_46

I had an apprentice bring a piece of wood gas main to class. He was working for a contractor that was replacing main in a Chicago suburb, it was still in use.

EBEBRATT-Ed

@bob That's pretty amazing. I am sure it dates back to the late 1800s

JUGHNE

I meant to move the reg close to the meter but still before it.
It sounds like the 12' low pressure pipe fm reg to meter is the main bottle neck?

ChrisL

Yes, they could reg down right before the meter to solve this problem, as there is about 15' of piping between the two right now. Not sure they would want the reg inside though. Even so, If they could just take out 2- 1 1/4 el's and and about 6' of 1 1/4" pipe and replace with 2", my problem would be solved.

Bottom line is I have to get to someone that has the knowledge and experience. Not asking a lot here, but most of those people have retired, and the remaining brains are higher up is my guess.

Chris