What do all the ratings on my gas meter mean?

bender1227

What do all the ratings on my gas meter mean and why are there two pipes coming into my house?

What does the 5psi mean, 250 C.H.F, and 1/2" Diff?

Picture 1: https://imgur.com/a/qnDoYhx
Picture 2: https://imgur.com/a/3vd32h9

I'm trying to get more educated on my gas system in my house.

Thanks!

Snowmelt

What comes out of your meter is mostly .5 psi and your meter is rated for 250 Cubic feet per hour.
If you google gas sizing charts they will be more exp.
The 250 psi is the size as you add appliances your meter needs more c.f.h. A c.f.h is about the same as btu of the equipment.

STEVEusaPA

They temperature compensate a natural gas meter?

JUGHNE

The 5 PSI is the maximum pressure the gas meter is rated to handle.
The CFH of 250 is typical for the average house.
Your house may have a load of maybe 150 CFH or so.

IIRC, the 1/2" diff is the pressure drop across allowed across the meter...not clear on that myself.

From what gas employee told me:
The temp compensation is now standard on gas meters.
The old gas meters were in basements to keep them at a moderate temp for correct reading.

In your pictures the gas comes in thru the wall below meter on the left side. Then thru the pressure dropping regulator.
The pressure thru the wall pipe might be a few PSI. 10-20 or so.
The regulator then puts out either 2 PSI or 4 ounces of gas pressure to feed your house.
If you have additional separate regulators at each appliance then you may have the 2 PSI thru your meter.

The second pipe goes up from the regulator vent and outside thru the wall....might have a little "shower head" looking device on the end outside, pointing down.
The regulator has a rubber diaphragm that moves to regulate the pressure. It has to "breathe" just like your lungs. The outside venting is there in the advent the diaphragm breaks and passes gas to the outside. The end of the vent has to always be open.

Today it is better to have the regulator and meter outside your house in the advent of leakage. Also it is better to have the underground gas line "break ground" up to the reg/meter and then thru the wall into your house.
If there are any under ground pipe leaks the gas tends to enter the basement thru the wall.
With the break ground method that leaking gas is more prone to come up thru the ground at the meter outside.

ChrisJ

The MAOP is Maxim Allowable Operating Pressure, 5 PSI.

The meter is rated to have a 1/2" drop in pressure across it at 250 CFH. If you try to use more gas through it, it will have a bigger drop. 250 CFH is roughly 250,000 btu/h.

That meter at 565 CFH has a 2" drop in pressure. That's not stated on the meter, but is in the information sheet for the meter.

This means at 250,000 BTU/H the pressure coming out of the meter will be 0.5" WC lower than what's going into the meter.

JUGHNE

ChrisJ, did your info have any stats about the accuracy of the meter if the CFH flow is doubled?

ChrisJ

JUGHNE said:

ChrisJ, did your info have any stats about the accuracy of the meter if the CFH flow is doubled?

Interesting thing is over time I've found two different data sheets and the 2" drop lists slightly different ratings, this one shows 583 cfh.

The "Proof" only goes to just above 250. So, who knows.
I told my gas co I'm at 350,000 btu/h and they said my 250 is fine for the job. *Shrug*.

mattmia2

ChrisJ said:

JUGHNE said:

ChrisJ, did your info have any stats about the accuracy of the meter if the CFH flow is doubled?

The "Proof" only goes to just above 250. So, who knows.
I told my gas co I'm at 350,000 btu/h and they said my 250 is fine for the job. *Shrug*.

You can only say that if you have done the engineering on the system and determined that the lower supply pressure to the system is OK. It is within the code to have more than a .5" drop in pressure in the distribution system as long as you as supplying within the rating plate supply pressure range to the appliance.

ChrisJ

mattmia2 said:

ChrisJ said:

JUGHNE said:

ChrisJ, did your info have any stats about the accuracy of the meter if the CFH flow is doubled?

The "Proof" only goes to just above 250. So, who knows.
I told my gas co I'm at 350,000 btu/h and they said my 250 is fine for the job. *Shrug*.

You can only say that if you have done the engineering on the system and determined that the lower supply pressure to the system is OK. It is within the code to have more than a .5" drop in pressure in the distribution system as long as you as supplying within the rating plate supply pressure range to the appliance.

It appears the utility can say whatever they want. Including insisting that you don't use everything at once, so it doesn't matter even when you assure them that you do and often.

I'm not saying it's correct, I'm not saying it's normal. And I'm certainly not saying it's safe. Because personally I feel it's not safe.

I'm just saying it's what I've been dealing with and I'm not exactly thrilled over it.

STEVEusaPA

Gas, Electric, and Water meters. Funny how I have to have my trucks meters tested yearly by Weights & Measures, but no one has any way to confirm calibration of these utility meters at your house.
The only time a utility will come out is if they think the meter is cheating them, never the other way around. When I switched from gas to oil, a month later they wanted to come out and check the meter because they thought it wasn't working.
However when I had a leaking flush valve at the shop, and my water bill went up 500%, no one called
Yes I know logistically it would be impossible to have them all checked.

ChrisJ

STEVEusaPA said:

Gas, Electric, and Water meters. Funny how I have to have my trucks meters tested yearly by Weights & Measures, but no one has any way to confirm calibration of these utility meters at your house.
The only time a utility will come out is if they think the meter is cheating them, never the other way around. When I switched from gas to oil, a month later they wanted to come out and check the meter because they thought it wasn't working.
However when I had a leaking flush valve at the shop, and my water bill went up 500%, no one called
Yes I know logistically it would be impossible to have them all checked.

I mean....
It seems just as possible as having all gas / diesel pumps and fuel truck meters checked yearly, no?

Of course, I also know who will pay for such services ultimately and it's not the utility. I'm happy with how it currently is.

JUGHNE

Most meters were/are mechanical devices.
Over time they would slow down in the customers favor.

We now have WIFI reading of electric, gas and water.
They have called people if their water consumption is out of line.
Previous water meters might not work at all.
This is where I found the 1000 gal/day running WC's after the utility called the customer.

As far as testing all meters, each house might have 3 from 3 different utilities. Gas, water and electric.
They have the history of each building and some will look at average usage for that location.
If lower than usual then there is interest.
If higher than usual then maybe it is looked at.
Years ago, if your electric bill tripled year around......then maybe you are a suspect for having grow lights....might not be a concern today.

mattmia2

Aren't public fuel pumps inspected annually or every couple years?

STEVEusaPA

Annually, just like any device used for commerce, including cash registers, scales, etc. Even the measuring stick at the register at Home Depot has a W&M sticker on it. But not utilities.

RyanD

STEVEusaPA said:

Annually, just like any device used for commerce, including cash registers, scales, etc. Even the measuring stick at the register at Home Depot has a W&M sticker on it. But not utilities.

In Massachusetts it gas meters seem to be replaced every seven years maybe this is why? I'm not sure if it's a state law or just common practice for the gas companies.

delta T

Not quite related, but a funny story of mine related to water metering. The first house I ever bought had an irrigation system. We closed in May and the previous owner thoughtfully offered to have his irrigation guy come over and turn the irrigation system on for me, but since I am a plumber I said no. I'll handle it. Not a big deal for me. Oops.....

Well......I did turn it on, adjusted the heads, set the program, made sure everything worked, and it did.

There was no indication. No water flowed out of the ground. No water showed up in the basement. Didn't hear any noise. But.....there was a buried open drain that I missed in the valve box.

The water usage was so high that one day while my wife and I were at work, the Sheriff was dispatched for a wellness check. He left a business card.

198,000 gallons in 30 days.

*sigh

A $1,700.00 water bill was payed off over 5 months and I learned an important lesson! I didn't argue the precision of the water meter.....it was definitely my fault.