can I buy a mini gas meter for boiler?

Plumbob

Maybe I'm anal, but I wanted to add a gas meter at our boiler, separate from the gas company's meter, in order to monitor boiler energy use separately from the domestic hot water, dryer, stove and oven.

Does such a thing exist? I couldn't find it easily on google. On ebay I can find standard utility companay type gas meters removed from homes, but I am not sure they were legally acquired by the seller, plus they're rather large for this purpose...I was thinking of a small meter, perhaps with a digital display.

Mike T., Swampeast MO

Am striking out for small units myself.

Here's a decent link, but they're big and expensive I'm sure.

http://www.gasindustries.com/articles/NewProds/oct03field.htm

Use submeter or sub-meter in your Google search string.

I have a feeling that the higher gas pressure on the utility side of the meter is what drives the mechanics and that it gets more difficult (not to mention restrictive) to mechanically measure the flow once the pressure has been dropped down to house level.

Plumbob

Thanks, you came closer to relevant products than I did. But still, none are few-hundred-dollar, consumer grade, "not legal for trade" convenience meters. Maybe there is no market for them.

Glenn Harrison_2

Try this link...

http://www.americanmeter.com/en/

I believe I got this link from Mark Eatherton, who has done exactly what you want to do.

Mark Eatherton1

Yup...

Thanks Glenn. The meter I bought can be purchased direct from Gas Equipment Company at 303-422-3403.

They have an option available that gives a pulsed contact closure for each cubic foot passing through the meter. When used with a HOBO state recorder, and a HOBO 4 channel temperature recorder, you can see to the minute what your system is doing...

Minutia, maybe. But if you want tight details, THIS is the way to go IMHO.

ME

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R. Kalia_3

wow

Wow, a meter almost as big as the Munchkin! I don't think I'll go that route, though, I was hoping for something small, maybe not completely accurate, but cheap.

DaveC

Maybe Dwyer Instruments?

(800) 872-9141 - General Sales / Tech Service #

I see turbine flow sensors and mass flow meters for gas, but the range and piping connections do not look appropriate for your use in their catalog - but maybe they offer something else?

Geo_2

meter

On a service call years back replacing a circulator for a guy when I saw these little tiny led counters on top of the boiler, this guy was some type of engineer and he installed these hour counters ( he bought at grainger)inline with all the thermostats ( 6 unit building). each opperated on 24 volts, had a 10 year battery and only came on when a unit called for heat,maybe something to look into.

Jeff Krawic

Gas meter

Hauck Manufacturing also has a method of measuring gas flows however it does not record. If it may be of any help to anyone out there, I believe their website is www.hauckburner.com. They are available in 3/8" pipe size, all the way up to 28" diameter. Maybe thisa will help. Good luck. Jeff Krawic

Plumbob

yeah but...

...many thermostats have built-in usage counters nowadays. They record the total time for which the thermostat has been calling for heat, which is useful information (I have one of those stats). They don't have any way to know how much gas is being used, but the system you described, which is "inline with the thermostats", doesn't either.

Geo_2

what thermostat does that??

Christian Egli

Flow meter

There are small flow meters that work for gases that are much smaller than the usual gas meter, they are probably slightly less accurate. We have used one on a compressed air line. Right now I can't find my information on it, it will require a little time, I hope I can get back to you.

Here is a thought that makes your idea better.

Efficiency ratings, too, do not seem as they appear. You all know how easy it is to have inconsistent measurements compared to what you read on labels. It would be nice to figure it out at all times.

Every BTU that goes into the boiler as measured by the gas meter comes out of it either in the hot water, up the chimney or through the jacket. Jacket losses are hard to measure, flue losses are also hard to measure beyond just a spot check. We're left with measuring the BTUs that come out with the water.

But that's easy, by installing 2 hot water BTU meters, one on the supply and one on the return; the difference between the two will be the net output of the boiler. If you are on steam with a pumped return, and you love it, put a water meter on the condensate return line (it should work on gravity systems, but mind the A dimension). What ever did not come out in net output went into losses.

Obviously this thought is more easily implemented on a new installation, but think of how fascinating it will be to watch the meters turn. Commercial applications should even call for real-time data acquisition. I’m going for it. The same will work for domestic hot water.

To put it in perspective, we all buy cars that have an odometer and we measure the gas by the gallon as we buy it. All the gas that did not come out on the miles per gallon computations was wasted. Simple. Note also how incoherent actual data is compared to the labeled values that were glued on the window when you bought the car.

Call it a heat-o-meter and compute your heat-per-gallon, your heat-per-CCF, your heat-per-therm. Measure your heat in BTU or pounds of steam. Knock yourself out but just don’t chop a tree near your new boiler.

Mark Eatherton1

You're missing something Christian...

If all you're looking at is delta T, you're missing a BIG part of the equation. GPM flow rate. On my system, I actuall have a flow meter installed ont he hydronic side, so I can see what GPM I'm moving. I have a one pipe system, so anytime the main circ is on, the GPM flow rate is fixed.

If I had the typical parallel multi zone system, I'd be screwed, even with the meter, because as different zones or combination of zones call, the flow rate varies.

Gallons times Pounds times Delta T = btu's delivered (sans time element).

Now if you could come up with a strap on flow meter (doppler effect) for pipes of less than 2" ID, you'd have a good start on the ultimate system for recording thermal efficiency.

ME

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Plumbob

usage tally?

Any Honeywell Chronotherm, and I used to have a Totaline that did that. You just have to go one or two levels above your basic Home Depot model, but even Home Depot may stock one that does this. Tallies today's hours, yesterday's hours, and total hours since last reset.

Plumbob

flow

ME already said this, but to emphasize, you can't get BTU without knowing the flow. Not just the current flow rate, but the total flow for the day or other period, if it is a system that goes on/off based on the stat or if the flow varies with time for other reasons like TRVs.

This would be great to know, but I'd still like to know the total cft of NG used.

Constantin

Try McMaster Carr, they have two excellent choices!

They offer gas meters starting at $150.... go to McMaster Carr and then have a look at page 469 of their catalog. On that page you can find an Aluminum unit that can output a signal for about $350, a plain-jane gas meter for $150.

McMaster Carr is your friend... ;-)

Plumbob

big though

Thanks for the lead, the price certainly works, but these are as big as a regular utility co meter. In fact they are regular utility co meters (reading is nonresettable).

Constantin

The Al ones may be resettable

...but only a call to McMaster would confirm that. Were I in the market, there would be one of two things I would consider:

1) get the Utility-style meter and modify it to output impulses that are captured by a CPU. I've seen folks do this somewhere online via the usage of a LED, a detector, and a small circuit.

2) the Al gas meter seems a bit more flexible and pre-configured for that kind of application. Unless you're handy with looking for the info and the soldering iron, this may be the more cost effective solution.

Cheers!

Christian Egli

The BTU meter

Sorry I got too many ideas jumbled. I mentioned the BTU meter, which is a gadget that measures both water temperature and flow, then makes some computations and totals up the heat that went through it. The dials show the running total in BTU, kWh, therm, etc.

They are very common in Europe, in apartment buildings and measure the winter heat use for each unit. They look just like regular water meters.

I looked up some other names for the BTU meter. I found heat totalizer, heat meter and aqua meter. Are there others? What is the popular name in your region?

http://www.istec-corp.com/btu.html

That is the site of a company that produces an item that would be perfect for measuring the net heat output of a boiler. Easily. The one unit uses three sensors, one temperature probe for the supply water, one temperature probe for the return, and one small turbine sensor to measure the water flow. The computed heat usage is then displayed. This device is much better than a BTU meter that relies only on one temperature probe and a flow sensor.

That is what is perfect for a hot water system. But for steam, things are different and much much more simple. Simple is better, no?

You're not measuring hot water anymore, you're measuring condensate. As such you don't need to bother registering supply and return temperatures. With the simple measurement of how many gallons of condensate that went through the system you can figure out how many BTU were released in the transformation of steam to condensate. But for the hot water systems, things are different.

So, that was two ideas.

Here's more.

The idea others have had in this tread to measure gas usage by simply installing an hour meter sounds like the easiest thing to implement as an afterthought.

Install the meter so it runs when the gas valve is open. Gas burners burn gas very accurately so it is very easy to get the gas consumption. If the label on the boiler says 100,000 BTU/h input, then it means that it will burn 100 cubic feet of natural gas per hour.

Over here we buy gas by the CCF (100 ft3), that means that this same boiler will burn 1 CCF per hour.

This will miss out on the pilot light usage which you would only pick up with a real gas meter, a volumetric one. The neat one ME shows in his picture.

The good people at McMasterCarr have at least a page full of hour meters, for all voltages, with and without zero reset.

The hour meter built into the room thermostat could be good enough if you know that the burner is on whenever there is a call for heat. That may or may not be the case in every system.

Christian Egli

Fancy flow meters and flow totalizers come in many different forms. There are those that use an orifice and measure a pressure difference, those that use a pitot tube, some rely on ultrasounds others on a small fow turbine.

None of these will be as convenient as the standard utilities meter. Plus, it seems you can find a gas meter for about $200, while I don't think any of the other methods con be found for that price.

The hour meter on the gas valve solution is dirt cheap by comparison and requires no plumbing work to install and will be very accurate.

You can easily calibrate your system against your utilities meter.

Hope I'm helping

Plumbob

yes

yes, you are helping a lot, thanks! How about another idea?

As I posted earlier, the hour meter connected to the gas valve open signal won't work with a modulating boiler. But you also mentioned something interesting, the BTU meter. Unfortunately, it needs a flow meter to be installed. But...

Our Munchkin has P/S piping, so the flow in the boiler loop never varies. I haven't measured it, but I can guess what it is using the pump and boiler head curves. Anyway, it is a constant, so one can get RELATIVE measurements simply by measuring delta-T, as we thought you were saying originally.

What one would need is a meter that totalizes delta-T * time, but not when the pump is off. One can do this without plumbing, with two temperature sensors and some wiring to detect whether the pump is on. however, I suspect that there is no device that does this, and my skills do not extend to wiring up such a device on a breadboard. It is basically the same as the BTU meter you gave a link to, except that it has to work even without a flow meter input, just a flow/noflow signal.

Munchkin could do this easily on their control board; all the information is there.

Plumbob

excellent idea, but not for a Munchkin!

> The idea others have

> had in this tread to measure gas usage by simply

> installing an hour meter sounds like the easiest

> thing to implement as an afterthought.

> Install the meter so it runs when the gas valve

> is open.


That would work in most cases and would be far more elegant than a bulky gas meter and plumbing changes. But we have a Munchkin and of course it has a modulating burner---I didn't mention that originally because I never thought it would become relevant!

I looked at the 925 board schematic and it does tell me where the burner wiring is, but it is presumbly an analog signal.

> The hour meter built into

> the room thermostat could be good enough if you

> know that the burner is on whenever there is a

> call for heat. That may or may not be the case in

> every system.


You are right, that won't work in general.

jerry scharf_2

If this is all you want to do

I don't think you need to buy anything (assuming you have a computer.). You can hook the munchkin up to a computer and pull the modulation level, inlet and outlet temps right out of the boiler. It also gives you the modulation level of the boiler.

If you buy a differential pressure guage (probably <$10 on ebay) and plumb it across the boiler pump, you can read that and look up the flow from the pump curve with good accuracy. As you said, the flow will be constant on this pump. If you have the vision package, you can move the guage to the indirect pump and get that one as well.

Some people may disagree, but my sense is that ultrasound flow meters are about the best. They are accurate and they have much less demand on the inlet/outlet piping. It can often be hard to fit the inlet/outlet piping in for a regular mechanical flow meter, and if you don't do it right the readings can be way off. Those gas utility flow totalizers aren't as accurate as you might think.

jerry

R. Kalia_5

yes but

> I don't think you need to buy anything (assuming

> you have a computer.). You can hook the munchkin

> up to a computer and pull the modulation level,

> inlet and outlet temps right out of the boiler.

> It also gives you the modulation level of the

> boiler.


If I understand correctly, this requires proprietary software provided by HTP to contractors. They don't offer them to homeowners. I may be wrong...I'll check.

Mark Eatherton1

Cheap gas valve clock...

I met a gent one time name Reverend John. This 69 year old retired Rverend and his wife traveled ALL over the country checking out solar hot water heating systems. He'd written some books ont he subject. ANyway, he takes me to his home, drags me to the furnace closet, opens the door and sitting there in front of the heater is a small electric clock. It is connected to a transformer (120/24) that is paralleled to the gas valves coil. When ever the gas valve is one, it boost the voltage to the electric clock and logs ON time.

He'd clocked his burner at the utility co meter so he knew how many therms/"hour" it would use. He could show you graphs of things most people don't even know exists!!

Quite the character, he was.

ME

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frugal

separate meter reading from one boiler for 4 unit building?

I heard that there is a new gas boiler that gives BTU readings for each zone- so that the owner can charge tenants for the actual heat they use. Real of wishful thinking?

Jeff Elston

Good Meters I found here

1. http://www.sunburstenergy.com/
   
   

Roland_18

domestic meter

http://excelamerica.amazonwebstore.com/GM-Daehan-Compact-Gas-Meter-Submeter/M/B003K9B3RC.htm?traffic_src=froogle&utm_medium=CSE&utm_source=froogle



I don't know if it has a recording output ,but, it is pretty small.