Water meter showing "leak" 24/7 after new steam boiler with indirect hot water

jrpsalazar

A week ago I had a new gas steam boiler installed with a 45 gallon indirect tank for domestic hot water. This system replaced an oil-fired boiler with tankless coil. I have a two family building with shared water main, and there is a already a second smaller gas boiler with a 30 gallon indirect tank, which has been running with no issues for about four years.

Since the new system came online the water meter has reported a small continuous incoming flow that amounts to a bit over one gallon an hour. The meter is a digital one, recording data minute by minute, which I can access and download. It is very clear the issue began a week ago around the time the indirect tank was filled (a very visible event in the data) and has been ongoing since then.

But there is no leak. Or if there is, it is completely invisible and silent and can't possibly add up to well over a hundred gallons of water over these past days. It amounts to 30% of my total water usage. So how can I diagnose what is going on? I've got the contractor scheduled to come back and take a look, but would love some advice.

ethicalpaul

Start shutting off valves until the usage goes to zero?

JUGHNE

Have you checked the apartments? Could be a running toilet or dripping faucet.

Have you watched the water level in the sight glass of the new boiler?

jrpsalazar

Thanks for the response. The flow does go away if I close the supply valves to the new boiler and indirect, and the domestic hot water valve coming out of the indirect. I still get hot water in this scenario to the rest of the existing plumbing by opening a valve that temporarily connects to the hot water supply for the other apartment. So I'm confident there is no leak in the plumbing to either apartment and that the "leak" is something to do with the new install.

I'm happy to post pictures if any would be helpful.

EBEBRATT-Ed

It's not evaporating so something is leaking. Outside faucet left on partially?

jrpsalazar

I should add some more info. I didn't want to write a whole novel before knowing if I would get a discussion going. This is the type of water meter I have: https://metron-us.com/spectrum-pd-positive-displacement-water-meter/ It has an LCD display I can watch, and when I don't have the boiler/indirect valves closed, I see it indicating "FORWARD" several times a minute and occasionally "REVERSE". And then eventually incrementing the counter by 1/100 of a cubic foot. So I know there is some kind of pressure fluctuation at the meter. And I'm not necessarily convinced that there actually is a net inflow of water. It could be the meter adding up the inflow but not subtracting the outflow, something like that.

jrpsalazar

But you're right, the water has to be somewhere if it's not a problem with the meter math. Is there any pressure situation that could cause hot water to come out of the indirect tank faster than cold goes in? So that then there is this slow catch-up trickle afterwards? I don't see how such a thing could be possible. But could trapped air do that somehow? And eventually this goes away.

bburd

Is there an expansion tank on the domestic hot water piping, probably near the indirect? Water expands when heated. If there isn't and your water meter is that sensitive, this might account for the effect you've seen— the "reverse" flow is what got my attention.

Jamie Hall

As has been said, start closing valves to isolate components or sections of piping, one by one.

If the meter is that sensitive you could have some peculiar effects, but if the total, by and large, rises over time you either have a leak — or a meter which, if not defective, is pretty useless.

pecmsg

or close everything off and slowly open one at a time

jrpsalazar

bburd, there isn't an expansion tank. I've been reading and learning about expansion tanks and backflow protection today as part of trying to figure this out. And thinking along the lines you are. An expansion tank seems like it could help.

What's mysterious to me though is why the observed effect of thermal expansion would not be time limited and correspond more clearly to boiler cycling. If I'm getting some kind of false meter reading, it seems there is small-scale turbulence at the meter every minute of every day.

jrpsalazar

"…or a meter which, if not defective, is pretty useless." Jamie Hall, the city water department was offensively rude when I called today to ask questions about how the meters work, lol. Granted they probably get a lot of angry calls from people with loose toilet flappers, but wow, they were unpleasant. We just had our meter replaced in March. They've been replacing everybody over the course of the past year. It's Progress, I guess. Anyone with access can now see exactly when and how often we flush, shower, use the dishwasher, etc.

Jamie Hall

I will probably annoy someone saying this, but… I see a lot of this sort of thing, in a lot of different areas. Someone in a bureaucracy has a wonderful idea of the latest and greatest new thing, and they push it out on everyone without adequate real world testing, and then when folks complain they get very defensive.

It's life.

Intplm.

@jrpsalazar

One area at a time in your case is the way to go…one at a time.

Shut valves off at the toilets and any other isolation valve that you have. Tag the valves as to what they serve and carefully trace the piping to each location as best you can, and slowly turn one at a time on and take careful notes. You will need to do this when no one else is around to avoid them inadvertently using the water. Take it slow and watch the meter with each valve being activated.

jrpsalazar

Thanks everyone for suggestions. Plumber who installed the system was out today and confirmed that there's no leak with the new equipment and no leak anywhere in my plumbing that could account for what the meter is reporting.

I posted on a local discussion board/social media site today (nextdoor.com) and within an hour had a response from someone in my city who saw the exact same problem after a boiler install. "My spouse, a retired engineer, traced it to 'jitter' caused by our high efficiency boiler which incremented the meter - not a leak." So we're going to compare notes.

Pretty sad and kind of outrageous if this is a systemic problem with these meters.

Intplm.

https://forum.heatinghelp.com/discussion/comment/1821829#Comment_1821829

If this is happening at other homes, then hopefully your water company will have an answer—maybe a meter that will not "jitter," and cause a waterfalse us billing situation.

jrpsalazar

So far I've spoken with two neighbors of mine who saw the same issue. Both of them had expansion tanks in their plumbing, which they removed to make their meter jitter go away. We generally have our plumbing open to the water mains in my city—at least, as far as I know. I can see I have no backflow protection on my main supply line on my side of things. No one who quoted me on the new boiler/indirect mentioned an expansion tank. And I don't have one, like I said above.

My neighbor's experiences make me wonder if I have air trapped somewhere though, in the indirect water tank itself or somewhere in the system. I've opened the pressure release valve on the indirect tank for a bit. And let air out at all the sinks/bathtubs. Not sure what else I could do in that vein. The indirect tank is not 100% level due to my basement floor. But it's close.