Stubborn leak where service meets house

[2002sheds]

Hi All,
The water pipe where the water from the street meets the pipe that goes into the house developed a leak the other day when a glue joint gave way.

The configuration is a little complicated by a code requirement that we have 1-1/2” pipe from the street for fire suppression. As you can see in the picture, a Tee comes off of the 1-1/2” pipe and joins the 3/4” pipe that supplies the house.

All of the PVC for the transition from the big pipe to the 3/4” (which is where the leak was) was replaced the other day with Push to Connect fittings for now, so as to get our water back on.

The only solution I could find for joining the repaired section of 1-1/2” pipe (all the way from the elbow underground to the straight section into the house) was to include a union. That is where the drip is now.

Measures taken so far with unsatisfactory results have been to simply tighten the union and (when that still had a drip) to tighten the union with Teflon tape on the threads and O ring lube on the O ring….

If there is a way to get solid piping for the entire section above the TEE, I’d love to hear about it.

And it doesn’t help that out water comes downhill from a tank and out of the pipe at around 85 PSI. I have only opened the valve at the street partway and still have tremendous pressure inside.

Thanks,
David

 

[wwhitney]

As far as pressure goes, when no water is flowing, the pressure is going to be the same whether the valve is open just a little or fully open. With flow, the pressure will drop quite a bit when the valve is open just a little.

As to getting rid of the union, someone else may have a better idea, but my first thought is to arrange the piping so that there is a flat (planar) U-shaped section. Then the last glue up operation would be to carefully glue both legs of the U-section simultaneously. For example, say the buried portion went a bit farther to the left, moving the riser to the left, and turning the top elbow to point to the right, with a new elbow to turn in to the house. Then the riser and the top and bottom elbows would be U-shaped.

However, I would think it would be desirable to have a main shutoff at the house. I understand that with fire sprinklers, any shutoff that turns off the sprinklers has to turn off all the domestic water as well. But that still allows a shutoff below the tee where the fire sprinkler and domestic branches separate. So perhaps some research would turn up a brass compression ball valve that can but used on pressure-rated PVC with a union on the house side.

Cheers, Wayne

 

[Sponsor]

 

[2002sheds]

Hi Wayne,
Thanks very much -- that is a cool solution! It will involve some more "surgery" that I will strongly consider.

In the meantime, maybe I can slow down the drip... I used teflon tape on the threads of the union as an attempt to stop the drip (it didn't). I just read the thread about tape versus pipe dope versus putty, and I am wondering if Megaloc or some other pipe dope might "stem the flow" for now...?

Thanks,
David

As far as pressure goes, when no water is flowing, the pressure is going to be the same whether the valve is open just a little or fully open. With flow, the pressure will drop quite a bit when the valve is open just a little.

As to getting rid of the union, someone else may have a better idea, but my first thought is to arrange the piping so that there is a flat (planar) U-shaped section. Then the last glue up operation would be to carefully glue both legs of the U-section simultaneously. For example, say the buried portion went a bit farther to the left, moving the riser to the left, and turning the top elbow to point to the right, with a new elbow to turn in to the house. Then the riser and the top and bottom elbows would be U-shaped.

However, I would think it would be desirable to have a main shutoff at the house. I understand that with fire sprinklers, any shutoff that turns off the sprinklers has to turn off all the domestic water as well. But that still allows a shutoff below the tee where the fire sprinkler and domestic branches separate. So perhaps some research would turn up a brass compression ball valve that can but used on pressure-rated PVC with a union on the house side.

Cheers, Wayne

 

[2002sheds]

Hi All,
UPDATE : A friend of mine said that if the surfaces of the union are not meeting perfectly (because the vertical pipes are not perfectly aligned) that the O ring at the mating surface may not get compressed enough on one side, allowing a small leak. I tested this idea by installing a simple plastic disc above the O ring, to see if the added thickness might help. No leak now !!!!

Today a plumber came by to check my work and recommend a more permanent solution. He is a pretty young guy, and thinks that the way to go is by using the ProPress system and Viega fittings for everything, starting from the pipe in the ground... his estimate was just under $2,000. Is ProPress the way to go? Are there other reliable configurations that will be really good but maybe slightly less expensive?

We'll go for the ProPress, if need be. I would just like to get some more perspective...


Thanks,
David