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-   -   Strange leak suspected (http://www.diychatroom.com/f7/strange-leak-suspected-78539/)

ctflea 08-12-2010 12:44 AM

Strange leak suspected
 
Hi Everyone,

I'm new to the forum and am hoping the experience here can help me solve a mystery for a novice such as myself.

On Monday, I had my plumber replace my old water heater, and while he was here, he also upgraded the shutoff valves to the 3 toilets in the house. Great. Well, the day after, I noticed that I could hear water flowing through the pipes in the garage, so I went to check the water meter. Lo and behold, the leak detector was spinning. However, after a period, it stopped.

As the likely suspect was an old fill valve in one of the toilets, so tonight, I replaced it, along with the other 2, which probably needed it also. However, I still hear the leak. The thing is, I only hear it after I have used water in the house somewhere, like flushed a toilet, or ran a faucet. It seems to flow for about 15 minutes and after that stops again. I came home at lunch today, to get a reading on the meter (no one had been in the house for several hours). When I came home later that evening, the reading was the same. So I know it isn't constant.

Any idea how I could be seeing this flow, and only after using water in the house first? I have no clue myself. By the way, I cannot claim that it started on Monday, but I was paying close attention, due to having had all the work done earlier in the day.

Thanks in advance,

Colin

TheEplumber 08-12-2010 01:07 AM

Any fluctuation in water pressure? Is your main shut off valve 100% open? Do you have any trap primers?

ctflea 08-12-2010 10:14 AM

Hi,

No, no fluctuations in pressure as far as I can tell. I never lose pressure when a shower/faucet is on, and the water meter never spins backwards. Not sure about the main valve (by this, I assume you don't mean the shutoff right next to the meter, but the second valve, closer to the house). And I'm not sure what a trap primer is. Could you explain? This is all new to me really.

Is it unusual to have flow that only occurs for a short period after usage? Last night, when it was happening, I closed the shut off valves at all 3 toilets ad every faucet, but not everything (new heater, fridge, showers) and nothing changed, so it doesn't appear that any of them are leaking.

Thanks,

Colin

ctflea 08-12-2010 10:45 AM

By the way, not sure if this is helpful information or not, but the house was built in 1996 and is located in Southern California. When the movement is occurring, I can see it on the meter, hear it in the garage, where the pipes are exposed, and hear it in the guest bathroom upstairs, where the pipes are not exposed. I cannot hear it anywhere else in the house. I don't think the toilets are running, as I replaced all the fill valves yesterday, and I don't get ghost flushes. No other faucet is visibly leaking.

Thanks,

Colin

ctflea 08-12-2010 02:02 PM

Fire System back flow valve the culprit?
 
So, I explained my new findings to my plumber this morning, and he had the hypothesis that it could be an issue with the fire sprinkler system. He suspected that the back flow valve on the system was bad, and than when we ran a faucet, water was coming from both the mains, and back from the fire system. Then, when the faucet was turned off, the 10 minutes of post-shut off flow was due to the fire system refilling.

Any merit to this thought?

Thanks,

Colin

TheEplumber 08-12-2010 09:28 PM

Quote:

Originally Posted by ctflea (Post 484683)
So, I explained my new findings to my plumber this morning, and he had the hypothesis that it could be an issue with the fire sprinkler system. He suspected that the back flow valve on the system was bad, and than when we ran a faucet, water was coming from both the mains, and back from the fire system. Then, when the faucet was turned off, the 10 minutes of post-shut off flow was due to the fire system refilling.

Any merit to this thought?

Thanks,

Colin

When was the last time you certified(tested) the BFV? Perhaps testing it would give you your answer. I don't think you want to drink fire water:no:
BTW, a trap primer releases a small amount of water to your seldom used Ptraps such as a floor drain. It could be out of sinc and releasing water for an extended time.

The Engineer 08-13-2010 01:11 PM

Quote:

Originally Posted by ctflea (Post 484683)
So, I explained my new findings to my plumber this morning, and he had the hypothesis that it could be an issue with the fire sprinkler system. He suspected that the back flow valve on the system was bad, and than when we ran a faucet, water was coming from both the mains, and back from the fire system. Then, when the faucet was turned off, the 10 minutes of post-shut off flow was due to the fire system refilling.

Any merit to this thought?

Thanks,

Colin

Can you describe your service entrance in more detail? Do you have a single water line from the street, then it splits in two directions inside your home, one to the water meter and the other to the sprinkler system? If this is the case, you should have pressure guages on the inlet and outlet sides of the backflow preventer serving the sprinkler system. One test you can do, is check the guages without any water running and the pressure should be close to the same give or take a few psi, then run some water somewhere in the house, and if the pressure guage on the OUTLET side of the backflow preventer drops, then you do have a faulty backflow preventer. The pressure on the outlet side should always be same, the inlet side guage will flucuate depending on what your running through the water meter at the time. Hope this helps.

ctflea 08-13-2010 03:42 PM

Hi,

I have a single water line from the meter. Passes through the shutoff, followed by a split for an external faucet (which is before the house pressure regulator). The main pipe then splits, with one to the house, that has the pressure regulator, the other to the sprinkler system.

The Sprinkler system branch has a backflow valve, followed by pressure guage and pressure release valve. The sprinkler guage is usually around 130psi (high water pressure in our neighborhood). Yesterday, after flushing a couple of toilets, it would sway between 125-131 for several minutes, while you could hear water flow, and see it on the meter. Then, eventually, the meter would stop, but the sound would continue. Finally, after 10-15 minutes, the sound would stop also.

This morning, I checked it after a shower, and the guage read 110psi, but made it's way back to 130psi before I left for work. I assume that the BFV should keep that guage absolutely still, right?

Does this help?

Thanks,

Colin


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