Need some help understanding my water tank & pump system.

[just.a.thought]

We had the same problem at our house and solved it by turning off the valve to the city water when the pressure is low or no water at all. When they build our project they initially installed water tanks and pumps at each house then later upgraded to the city water mains by running a line directly into the house pipes so when the pressure is low and the pump is switched on the pump will pump the water from the tank into the city water mains. When the city water pressure is ok we just unplug the pump and use it as a back up.

Edited July 14, 2017 by just.a.thought

[MW72]

Something simple for you to check OP. Shut off valves E & F. Are there any outlets that still have water pressure. If not then chances are that pipe D is a bypass as Crossy suspects. To confirm open E & F again and close C and check for water at the outlets. If you have water then that confirms the main bypass. If it is a mains bypass then there could be an intermittent fault with your pump. Sometimes it pumps and the pressure is fine and sometimes the fault occurs and the mains kicks in at a lower pressure.

 

If this is the case then time for a new pump. They are pretty cheap. I wouldn't worry about the tank. Not likely to be the cause of your problem.

[SOUTHERNSTAR]

OP single storey or 2 storey house? If a 2 storey you may find that they installed cheaper pump thats not suitable to pump the height needed. If a single storey it will be the pressure regulating mechanism on the pump or a faulty seal. If it was dirt clogging the system the pressure will be always be low. If it is a shortage of water the pump will be running without water coming out of the taps. 

[sappersrest]

On 7/14/2017 at 5:01 PM, williamgeorgeallen said:

it is unlikely line A is feeding into the top of the tank via an internal line and probably has a backflow valve on it. this is a bad system and did not work well in one of my houses. line A needs to be run externally and dump into the top of the tank with a ballcock shut off. as long as the tank stays full and your pump is functional you should be good to go. hope this helps.

It feeds via an internal pipe , just go to any diy store and have a look.

[Crossy]

5 hours ago, sappersrest said:

It feeds via an internal pipe , just go to any diy store and have a look.

 

Yup, ours is the same.

[VocalNeal]

When you get back. Shut E & F and see if you still have water anywhere in the house. It could be that D used to have a check valve so when the pump starts it is pumping water into the mains water pipe?

 

Find your water meter and shut off the supply to the house. Have a shower see what happens. If at some point you can hear water "entering" the tank, the system is short circuiting through D

 

Mike

Edited July 17, 2017 by VocalNeal

[CrashTestDummy]

Alright, I'm back - Sorry for the delayed response. I played around with the system and figured out a few things (see updated image).

 

Per the head guard for the moo baan, 'D' is a check valve. I found that when I turn off valves A, B and C water still flows to the house, so it must be coming from D. Is this normal? 

 

Regarding pressure, it's not too bad to the lower level. I found the pressure is really lousy to the second floor of the house if the pump doesn't decide to turn on. The pump is inconsistent when it turns on. For example, if I turn on a sink in an upstairs bathroom, the pump usually stays off and the pressure is low. But if I leave the sink running and turn on the shower, the pump sometimes turns on and then the sink water pressure increases. 

 

It seems it's just time for a new pump. 

 

[lopburi3]

I would cut out or replace "D" with the same on/off control used everywhere else and only turn on in case of a power failure myself - use pump for normal home water pressure.  It does not cost that much to do so and you will have less chlorine smell in your water as it will have time to age a bit in main water tank.

[VocalNeal]

From your picture D is not big enough to be a check valve. Turn off the water at the meter near the street, then turn on a sink and the shower and flush a toilet to get the pump to start.  Then listen or look in the tank. If water is entering I am correct. Instal a new check valve and start again.

 

If not we will have to look at the pressure switch adjustment.

 

Are you in BKK?

Edited July 27, 2017 by VocalNeal

[Crossy]

@VocalNeal D is easily big enough to be a check valve, I'm 99.9% certain that's what it is.

 

What our OP is seeing is pretty standard if using the automatic bypass idea with a decent mains water pressure.

 

Adding a regular ball/gate valve in the blue pipe below D would make it run "pump pressure only".

[VocalNeal]

OK I see it now after having enlarged the picture. It is bronze the same colour as the wall. I missed it in the OP's photo as it is small. 

 

That doesn't mean it isn't bypassing and dumping his pressure back into the main. I would still check just to be sure.

 

Now we need a picture of the pump.

[Artisi]

54 minutes ago, VocalNeal said:

OK I see it now after having enlarged the picture. It is bronze the same colour as the wall. I missed it in the OP's photo as it is small. 

 

That doesn't mean it isn't bypassing and dumping his pressure back into the main. I would still check just to be sure.

 

Now we need a picture of the pump.

that was my next question - possibly the pipe system is sorted - how about we look at the pump and the way it is installed and why you have problems upstairs

[CrashTestDummy]

On 7/27/2017 at 9:30 AM, VocalNeal said:

Now we need a picture of the pump.

Here's some pictures of the pump. It's a bit tricky to photograph with the cover stuck over it. The pump's old and due for replacement. 

[CrashTestDummy]

On 7/27/2017 at 9:19 AM, Crossy said:

 

Adding a regular ball/gate valve in the blue pipe below D would make it run "pump pressure only".

I think this is what I've been looking for. Obviously the pump's due for replacement, but I want to make sure I don't have the same issues with a new pump. Ideally, I'd just have consistent pressure the whole time by always running on pump pressure. The pressure from the meter is unreliable and totally inconsistent. 

[lopburi3]

The pump will have a high and low pressure setting so water will always be within that range (unless every tap open and pump not powerful enough).  For two stories you will probably want more than the smallest - but if you do not require too much pressure they are not that expensive.  Best to ask around and see what types other are happy with in your area.

[Crossy]

That controller is a flow type (constant pressure), starts on a pressure reduction, runs until the flow stops. We have one on the garden pump, unreliable.

 

Get a proper integrated (all in one) pump, they're not awfully expensive. Talk to your local pump shop for recommendations.

 

[CrashTestDummy]

On 7/31/2017 at 4:55 AM, Crossy said:

That controller is a flow type (constant pressure), starts on a pressure reduction, runs until the flow stops. We have one on the garden pump, unreliable.

 

Get a proper integrated (all in one) pump, they're not awfully expensive. Talk to your local pump shop for recommendations.

 

Could I trouble you to give me a couple examples of an "integrated (all in one) pump"? 

 

It seems everything I'm finding is this style:

 

Edited August 1, 2017 by CrashTestDummy
Image formatting

[wayned]

I have thre Mitsubishi WP-255 water pumps. https://www.homepro.co.th/product/1049580

[lopburi3]

Indeed those are all in one well pumps that are normally used here.  The pump in mounted on a small pressure storage tank and keeps that tank between set PSI and that tank in turn feeds your home.  There is a small pressure drop before pump starts again but most people are happy with it.  They also make a constant pressure type version where pump is always on when water being drawn (normally rectangular in shape.  I have not used the cheaper versions but the much higher priced Grundfos units are excellent (but probably overkill for your use).