Clocking my meter (and adjusting burners?)

Hap_Hazzard

It's been a few years since I last clocked my meter, so I thought it might be a good idea to check it again. To be accurate, I used the stopwatch on my iPhone to capture ten consecutive revolutions of the half foot dial and average them. The results surprised me for two reasons.

Lap 1:  14.00
Lap 2:  17.20
Lap 3:  17.02
Lap 4:  11.73
Lap 5:  14.56
Lap 6:  17.28
Lap 7:  16.91
Lap 8:  11.51
Lap 9:  14.55
Lap 10: 17.48
Avg.:   15.224

The first surprise is the sample variance. It's huge! And I can't chalk it up to sampling error. I didn't take my eye off the dial the whole time, and besides, the pointer seemed to pause and then jump ahead from time to time. So I'm wondering, is this typical for gas meter accuracy, and are 10 consecutive samples enough?

The second surprise is that, when I look up the ft³/hr for the average value and convert it to BTUH I get 120,000. the input BTUH for my boiler is supposed to be 160,000. This seems pretty low, considering it seems to be heating pretty well. Should I turn it up a little and then have the flue gases analyzed again?

ethicalpaul

I have seen this same behavior. Rather than timing 10 cycles and adding them together, you can eliminate a lot of the human thumb error by starting the timer, counting 10 revs, then noting the total time (or do both by using a "lap" function on your timer).

Hap_Hazzard

That's what I did—used the lap button.

JUGHNE

I have seen this on older meters. Erratic movement and even stopping and then moving again without a jump to "catch up".

If you called the gas company and told them your meter was not recording all the gas passed to your house, I am sure they would respond........

ethicalpaul

Hap_Hazzard said:

That's what I did—used the lap button.

OK, then just ignore the individual times and take the total time divided by 10 to remove the need to add them up.

but to reiterate, yes, my meter jumps like that too. You can also use the 2 foot dial, you probably know that.

EdTheHeaterMan

Looks like your meter may be doing you a favor. I'm not sure you want to call the gas company unless you want a new meter that is more accurate. (Read between the lines) To quote the famous moralist J. Cricket "Always let your conscience be your guide"

Hap_Hazzard

JUGHNE said:

I have seen this on older meters. Erratic movement and even stopping and then moving again without a jump to "catch up".

If you called the gas company and told them your meter was not recording all the gas passed to your house, I am sure they would respond........

Funny you should mention that. My meter stopped working a few years ago. I didn't notice until we got into heating season and saw that I wasn't being charged for gas, but then, going back through my bills I could see that there were no charges for months.

I assumed they'd charge me based on my average consumption over the last few years or something, but they didn't, so next time I might not notice it for a year or two.

Seriously, if I were the gas company, I wouldn't wait for my customers to tell me when they're getting free gas.

I wonder if the twitchy meter needle is an indication that the mechanism is about to break again.

Hap_Hazzard

ethicalpaul said:

OK, then just ignore the individual times and take the total time divided by 10 to remove the need to add them up.

Not surprisingly, it works out to the same number. But I'm still wondering if 10 revolutions is enough, and also, the bigger question, should I dial up my burners? They're running about 25% low. That seems like a lot.

ethicalpaul

What's your manifold pressure?

Hap_Hazzard

I don't have a manometer.

ethicalpaul

I like this one: https://www.amazon.com/Manometer-Pressure-Differential-Diameter-Hti-Xintai/dp/B07R3J4ZJ4/ref=sr_1_3?crid=332XYR6487Z5A&keywords=manometer+gas+pressure+tester&qid=1576778745&sprefix=manome,aps,130&sr=8-3&th=1

I wouldn't feel comfortable adjusting the pressure without one. And plenty of folks still wouldn't be comfortable without a combustion tester and the training to read it, I think, but I think of the decades before they were used and I don't get too worked up.

Hap_Hazzard

I was looking at combu$tion analyzer$ la$t night. They look kinda pricey, and you have to replace the $ensor$ every 2 year$ at $100 a pop. Yike$! I think it cost me well under a c-note to have someone come out and check it for me, and we had a nice chat. He said he'd taken one of Dan's courses.

I might go for the manometer though.

mattmia2

I assume you made sure nothing else was firing at the time.

That variance is more than the time it takes you to press the button.

Could be a mechanical problem in the meter is causing it to under read.

I suppose the next thing to do is to get out the manometer and make sure the regulators are keeping the pressure constant at the meter, at the appliance, and most importantly at the manifold of the appliance. The meter measures volume so if the pressure isn't constant the flow rate will vary if the appliance is firing at a constant rate.

Hap_Hazzard

Nothing but the water heater's pilot light, which is negligible. When the boiler shuts off, you'd have to watch that needle for a long time to see it move, and that's with both pilots running. There's nothing that would account for the jerkiness but the meter itself.

nde

Crazy the gas supplier did not notice the free gas! Sound like they need a new meter supplier.

Hap_Hazzard

nde said:

Crazy the gas supplier did not notice the free gas! Sound like they need a new meter supplier.

They probably go with the lowest bidder.

I don't mind being on the honor system for heating fuel.

acwagner

Can you clock it against a different gas appliance as a test? Water heater perhaps? That should give you good indication if it's the meter or the boiler firing rate.

Hap_Hazzard

I could try looking at it when the water heater is running to see if it's as jerky, but it uses a lot less gas.

I'm pretty sure it's the meter though. I've spent some time gazing at the burner flames, and there's nothing hurky-jerky going on in there.

mattmia2

It could be the meter regulator as well, if the pressure is varying then the flow through the meter will vary as the same mass of gas moves in to the appliance.

Maybe they should purchase some new meters instead of reconditioning the same ones they bought in 1955...

JUGHNE

Is your meter outside or in the basement?
Picture of the model number.....maybe a date code?

Hap_Hazzard

It's outside. Behind a bush. But I was able to get this snapshot.

ethicalpaul

You have to go outside to clock it?? That’s a drag! Mine is 8 feet from my boiler

Hap_Hazzard

That's okay. I only need to check it in the winter.

CantabHeat

I usually time the 2 foot meter and it rarely differs by more than a second. Meter is “jerky” in that the dial briefly pauses on a cycle before moving again but the reading and flow do seem very consistent provided another gas appliance doesn’t kick on.

mattmia2

There are 2 sets of bellows that alternately fill and empty that are connected to linkage that move the dial. Perhaps the low segments are where the bellows and valves transiting from filling one set of bellows to filling the other set.

Hap_Hazzard

ethicalpaul said:

I like this one: https://www.amazon.com/Manometer-Pressure-Differential-Diameter-Hti-Xintai/dp/B07R3J4ZJ4/ref=sr_1_3?crid=332XYR6487Z5A&keywords=manometer+gas+pressure+tester&qid=1576778745&sprefix=manome,aps,130&sr=8-3&th=1

I wouldn't feel comfortable adjusting the pressure without one. And plenty of folks still wouldn't be comfortable without a combustion tester and the training to read it, I think, but I think of the decades before they were used and I don't get too worked up.

Okay, so I got a manometer for Christmas, and I think I've figured out how to hook it up, but what kind of number am I looking for?

ethicalpaul

Your boiler plate should say what the manifold pressure should be in inches of water (it's probably 3.5). On your valve there is likely a test port for the manifold and a setscrew for the pressure to it.

https://www.behler-young.com/tech-tips/furnace-tips/setting-gas-pressure-residential-furnaces

This gives you a starting point for setting the pressure and it will show you if your gas supply is able to hold that pressure even when some or all of your appliances are running.

After this, one would use a combustion analyzer to really dial it in and check the combustion gases, but I think of all the decades where those didn't exist.

JUGHNE

IIWM, and had only one meter, I would monitor the inlet first and watch the pressure drop as all appliances including the boiler were turned on.
After being satisfied that the house inlet pressure was stable then connect to the outlet of the boiler gas valve itself to monitor that while firing. Nameplate or spec book would give you the desired basic number for WC.

Hap_Hazzard

JUGHNE said:

IIWM, and had only one meter, I would monitor the inlet first and watch the pressure drop as all appliances including the boiler were turned on.
After being satisfied that the house inlet pressure was stable then connect to the outlet of the boiler gas valve itself to monitor that while firing. Nameplate or spec book would give you the desired basic number for WC.

The gas control manual doesn't show a tap for inlet pressure, so I'd have to find a convenient place to add a fitting to my gas line. I am kind of curious to see what the supply pressure is, but I'm not sure I want to get into that right now. I'm planning on re-routing the gas line this summer.

Hap_Hazzard

Update: I found the inlet pressure tap.


Oddly enough, I found it in a PDF version of the manual I found online. The figure in the manual supplied with my boiler is almost identical, except the item labeled "INLET PRESSURE TAP (OPTIONAL)" in the above is not identified.

ethicalpaul

@JUGHNE that sounds perfect, thanks for providing those steps.

edit: oh yeah, and on my valve at least, it's clockwise to increase the pressure and counter-clockwise to decrease the pressure as provided by the output regulator. It's a very fine adjustment.