Trouble Shoot a water line 1

[ras717]

I have a water distribution system. The maintenance crew has shut off some valves to do maintenance on the line and they are getting lower pressures in the line than when they had the valves open. Does anyone have a reason why? I don't have a background in water systems and I'm being asked to trouble shoot this.

Thanks for any insight.

 

[KiwiMace]

Ooh me first!! They are measuring the pressure downstream of the shut valves!

 

[ras717]

Well, the person who went out to investigate came back and I got a better story of the situation. We are on a very steep hillside. Above this neighborhood they shut off some valves to isolate a section of pipe to put in a check valve. Below this area another neighbor lost water. A few homes have a little water on the first floor but none on the second. Supposedly, that area is serviced by another line and the pressure at the beginning of that neighborhood at a hydrant is 70 psi. The elevation difference from the hydrant to the highest point in the neighborhood is 60 ft.

I conclude that 1) the area was probably serviced by one of the lines they shut off - their maps are wrong 2)not enough pressure from the other line to provide service to compensate for the other line not in service. Am I right?

 

[zdas04]

60 ft of water is the same as 26 psi so the 70 psi becomes 44 psi available. The friction drop in the mains and feeder lines could easily eat this up before getting to the second floors (I'm assuming that the 60 ft elevation change is in the distribution pipe and that the water must still go up to the second floor after leaving your system).

David

 

[ras717]

Thanks David. This is what I came up after getting all the facts correct. The maintenance crew called in a twizzy.

Renee