Maybe somebody can explain this plumbing mystery to me.

Been in this home for 12 years now.

When the electricity power goes out and so the water pump doesn’t run, I close the blue valve which is the water line running forward of the pump and is the main water line into the home.

I then open the bypass water line- the red valve- which runs into the home directly from the municipality without need for electrical pumping…pressure isn’t great but it’s usually enough for a short period.

(see pic fyi)

Last evening the electricity went out.  As I have so often done, I closed the blue valve, opened the red valve…and went back inside the home.

I discovered the in the master bathroom shower, water was dripping from the shower head. It would not stop dripping.

Of course the faucets/valves were off/closed; and I thought maybe some sort of pressurization differential…there were no water anomalies in any of the other showers or any other point inside the house.

It continued to drip until the power was restored and I closed the red valve and re-opened the blue valve.

This has never happened before…anybody venture to explain why this happened?

Thank you…..

IMG_8990.jpg

There is "play" in one of your bathroom faucets. It is most likely a ball valve. When the pressure is high/normal the pressure against the "ball" keeps the valve sealed. When the pressure is marginal there is not enough pressure to keep the valve completely sealed.

Edit: Usually a shower heater system has two valves. One on the wall and a plastic one in the filter unit at the actual heater. When pressure is low close them both?

Edited July 10Jul 10 by VocalNeal

21 hours ago, VocalNeal said:

There is "play" in one of your bathroom faucets. It is most likely a ball valve. When the pressure is high/normal the pressure against the "ball" keeps the valve sealed. When the pressure is marginal there is not enough pressure to keep the valve completely sealed.

Edit: Usually a shower heater system has two valves. One on the wall and a plastic one in the filter unit at the actual heater. When pressure is low close them both?

Thanks for your advice. Here's a pic of the shower faucet setup. Hot water flows into the shower from the hot water on demand heater located under the bathroom sinks cabinet. Cold water flows into the shower by a direct water line. The mix of the desired water temp is managed by increasing/reducing the water flows using the faucet shown. Water flows either from the handheld shower head or the rain shower head as controlled by the central diverter. I suspect the diverter in the shower has a faulty O ring or some particles that need to be cleaned out to get the needed solid fit...I will check it out. Hope this makes sense.....

If you have time on your hands,

And the Taps on the shower mixer only turn 90 Degrees then it maybe a Ball Valve or a Gate Valve with a Ceramic Seat, the only way to tell is to remove the Tap Head/Handle.

If it's a Ceramic Plug/Seat arrangement 12Baht from Shopee, 2 minute job, easy fix.

If the Taps turn more than 90Degrees it's a conventional plug and seat arrangement, the rubber seat (Tap Washer) might of hardened and need replacement, again a cheap fix

Note, some mixers also have 2 spring loaded valves which act as a secondary form of isolation using the hydraulic water pressure when the Water is turned off, seen this in the UK, water turns on and off at night for no reason (Like it's haunted)

Our shower drips and has done for months. Unfortunately the tap providing water to the shower is plumbed in and cannot be easily dismantled. Not a big issue, we keep a water bin next to it for the times when water is cut off, we just let it drip into it. It is only a couple of litres a day, and the water still gets used.