27 minutes ago, cjinchiangrai said:

It will have a priming bottle on top

https://ecatalog-media.homepro.co.th/homepro/ART_IMAGE/12/700/1270022/447x447/30082024_1270022$Imagec3.jpg

That yellow gunk is from the fire extinguisher foam. The pool pump (in the same little cubby) burnt out recently, and I had them clean it. Guess they didn't lift the lid to clean the pump, too.

Sigh.

40 minutes ago, cjinchiangrai said:

It will have a priming bottle on top

https://ecatalog-media.homepro.co.th/homepro/ART_IMAGE/12/700/1270022/447x447/30082024_1270022$Imagec3.jpg

That is not a priming bottle.

It is an airbell. Function is to stop water hammer when the pump stops and starts. Should have 8psi pressure when at rest.

The pump shown in the OP's picture is the correct type for his installation

Can we assume it is the Hitachi (grey) pump that is not pumping?

If it is the Hitachi pump then my money is on the check valve seal or the spring that holds the check valve down.

The water in the pump is leaking back down into the tank and the pump is starting dry.

Both parts will be available at a Hitachi pump shop.

In the Hitachi (grey) picture the check valve is under the three bolts on the left.

5 hours ago, BuffaloRider said:

That's just a lidar sensor you can find any lidar sensor does the same

And you point is?

I posted the picture as an example. I'm well aware of level sensors having spent 50 years involved with instrumentation and control.

By the way, the picture is of an ultrasonic level transmitter, not a radar or laser level transmitter.

2 hours ago, emptypockets said:

I'm well aware of level sensors having spent 50 years involved with instrumentation and control.

Only 50? You are falling behind. Hahaha 🧓

5 minutes ago, VocalNeal said:

Only 50? You are falling behind. Hahaha 🧓

How so?

7 minutes ago, emptypockets said:

How so?

Only 50.... 😉🤔

Although from a process industry/user rather than a manufacture/service/repair point of view I am only at about 52. 🧐

10 hours ago, couchpotato said:

Bit more from above post....A new above ground tank (DOS or similar 1000/2000 litres) with a Mitsu or Hitachi pump with installation, would be +- 15.000 baht. The mains water inlet and tank outlet should be easy to find, so installation no more than a few hours. Although a new electric outlet for the pump might be required. You could have it in by this evening.

i know this doesn't solve your immediate problem, but as others have said, the setup you have now is not viable.

I got a Dos tank 1000 ltr for 1900 baht about 2 years ago from a large construction shop and it wasnt on offer or anything , I got a hitachi pump for 6000 baht no need to spend a fortune cheap pumps are available for around 2000 bt tanks can be expensive I was surprised by the price of the green Dos tanks

you mentioned a pool ? well there's the goto solution in an emergency, a refreshing swim , just go easy on the soap and remember to put a bit of extra chlorine in

On 4/9/2026 at 7:39 AM, Na Fan said:

... and it just randomly started working again.

It's always like this, and then the technician shows up hours later, and goes like 'everything is fine!'

😵‍💫

Something is either blocking the inlet or outlet - Can you blow air back down the pipe through the pump and back into the tank? Could be something blocking the pick up.

If you can blow, can you suck? enough to get water through? If you are getting mostly air when sucking, the pump might be losing its prime. Lots and lots of plasticine over every nut and bolt around the pump housing. Does the pump need priming? Should have a screw or cover that you can open and fill with water, Strange 4 techs can't fix it.

What is supplying the underground tank? If it's a well, it might be low, close to being dry, or the intake hose might be touching the water when the level increases and not when it's going down. The drought season has this happen to wells, including mine, where the pump will be working but the well is too low to be able to supply the tank. When the water level increases, this is why you're getting water for awhile. Just a thought.

On 4/9/2026 at 8:37 AM, couchpotato said:

15.000 baht.

can be done much cheaper, especially if not own property
water tank 2500-4000
pump 2200-5000

14 hours ago, Bday Prang said:

I was surprised by the price of the green Dos tanks

Yes those DOS greenery ones were cheap
though they are not so cheap anymore
we paid 2000B for 2500L tank
that was 4 years ago though, no offer just cheap
in comparison we paid like 18k for steel 2000L for our main house

22 hours ago, cjinchiangrai said:

It could also be airlock. Do you have the correct type of pump, with the priming bottle on top?

Good advice,

Since the tank is underground ground pump above/ground level every time there is no water in tank the pump gets air and won’t work.

As long as you don't know IF there is water in the tank below it's absolutley useless to discuss things like sensors, new pumps etc.

You have to get access to that tank and check if there is water in it.

If this overflow ball valve gets stuck, and that happens very often with these after a few years, you have your problem solved fo a few 100baht.

The symptoms are lacking enough details to diagnose properly.

The OP seems to be ruling out investigating the underground tank.

I suggest disconnecting the pump inlet and connecting it to a dustbin full of water and see if the house gets water.

That way you can be sure where to look next.

With an intermittent fault like this it is often a split supply pipe that is letting in air and stopping the pump from drawing up water on occasions.

I presume the underground tank supplies the pool as well.

If the pool and house draw water from the tank through the same pipe then those pipes will have to be checked or isolated as well.

To be honest the pool piping looks undersized to me but I don't know the size of your pool.

My pool uses 2 inch pipes but yours is using 1 inch.

On 4/9/2026 at 9:14 AM, BuffaloRider said:

That's just a lidar sensor you can find any lidar sensor does the same

What you dislike about it, that is what it is, with a 3D printed mold, solar panel and battery. You can build this stuff for a few dollars with arduino kits and similar as well.

First thing I would try is to remove the water meter, there is a removable filter in there that can get blocked and restrict the water flow

On 4/9/2026 at 5:11 AM, Na Fan said:

I've seen both happen.

This morning, at times, after opening the tap and leaving it open, the pump outside was silent.

Later, the pump was making noise, but there was still no water coming out of the tap, aside from a teeny tiny little stream. No real pressure.

Checked several different taps, all had the same issue.

Some other days, there was zero water out of the tap, no small stream, not a drop.

What makes this so weird is the huge variety of symptoms.

The start of the pump is done by a pressure switch in outlet pump.

You say opening valves and then silent pump.

pressure switch isnt working properly or is, but then no power to motor.

Or is not working due to blockages further in outlet pipe line. Blockages what will hold pressure and therefor pump will not run. No water or less coming out.

Maybe sometimes drop and pump starts, but then blockage hold it again.

Corroded contacts on switch. Not acting, switch is broken, though you say pump was replaced, new one?

Did they connect it right? Setting of pressure switch is right?, it is adjustable.

DO you have a level regulated, valve of tanks? Or is the pressure of city water continuous on tanks?

Contain the tanks a vent?

Power cable has an issue (broken, half broken, isolation not proper anymore) and no power or sometimes is, is going to switch.

No power is going to pump to start but switch could be working.

The pump makes noise sometimes, too less electric power to pump (voltage drop, isolation problems)?

Too less power, of cable not right or corroded contacts any where in electric line.

You say sometimes work, not much water and making noise.

You can measure it (voltage) but be aware it is electric, dont make mistakes as you could end up dead.

Be aware what you are doing. See if it is protected in main by a RCBO.

Choose right setting on meter and connect the probes in the right place, VOLTAGE.

Protect yourself with rubber not conducting gloves.

Are you sure, the valves you open are on the outlet line of pump? Did they connect it right?

If you open valve, pressure is down and switch have to act to start pump.

Switching 230 Volts.

Pump is not self sucking and the inlet pipe of pump must be always completely filled with water.

A return valve should control that, mostly included in pump housing.

However again you say replacing pump with new one. But inlet pipe must be completely filled with water.

There is a limit on length of inlet pipe pump due to use centrifugal pump.

Additional length of pipe and bends , valves , which increase resistance.

Your tank is already 2 meters down? Yes im aware the suction pipe should be full of water up to level in tanks, communicating levels. But also that last piece of pipe line to pump (suction pump) must be full of water. As your tanks are down, there should have been also a non return valve in outlet of tank.

Water shouldnt run back again in tank and to fill up suction pipe of pump in case of replacement and so, you need to block. and have a fill up possibility of suction pipe of pump.

You replaced pump, but did you completely fill up te suction pipe again.

Law of centrifugal pump. NO air.

Are valves in the system all open (not your house valves)? OK, but weird things do happen !

You dont have that problem with a submersible, jet pump. However your tank is hard to get too, underground, buried.

Switch OFF power before working on electric !

So what you could do, is have a good with socket connection cable and direct connect it to the pump.

NOT on pressure switch, override it, but directly on motor pump. I dont know if you have a socket connection at your pump. Of course all is powerless, be sure of that. Measure !

DONT use the standard cable (used for normal power), but another one.

If you connected it right, you start with open some valves in house, so there would be a flow if you are going to start pump. If valves are open, plug in the new cable of the pump in the socket.

Cable doesnt have to be real heavy, 1,5 mm2 is ok.

Pump should start to work and you can check the opened valves in house to see if water is really flowing out of them. If so, the whole watersystem is working good. Be aware when to start that , the inlet of the pump is full of water, NO air !

Of course I have no clue on how technical you are and can do.

If not working properly, you have problem in line in/out of pump (blockages).

You also could have problem with pump, it has been replaced, I know. But Murphy's law is always around.

The pump should have a normal smooth nice sound running.

If it jitters, there still could be air in the suction pipe. It could fade out, if it is not too much.

If all is running well at that point, you have to conclude , it is in electric cable normally used or the switch.

As pump has been replaced to new one, then it should be in power line cable. However Murphy's law.

Within that same law, you could have multiple problems.

3 hours ago, xtrnuno41 said:

Setting of pressure switch is right?, it is adjustable.

The pressure switches on these pumps are NOT adjustable.

On 4/9/2026 at 6:58 AM, Na Fan said:

4 "technician" people tried. Yet water keeps failing.

• Open the tap, pump won't start, water drizzles.

• Other times, there's randomly no water for an hour. Then back to normal.

They've replaced the pump. They've fixed this and that random bit.

I'm thinking they are guessing and don't know what they're doing. Owner is cooperative, but also isn't water-tech-savvy, and neither am I.

I need someone who does know what they're doing.

Recommendation, please, this is getting dire. I have house guests and we just woke up again and nobody can shower.

We are in Pattaya.

bit late but i am quiet an expert when it comes to pumps and no water.
1st. Do you have your own well?
2nd Have you checked the ground water level? is there still enough?
3rd does your pump sound funny, like it has some air in it?

There can be some reasons but not too many actually.
If i can hear it, i can let you know better

8 hours ago, NanLaew said:

The pressure switches on these pumps are NOT adjustable.

they kind of are, but its complicated. Often it is indeed the pressure switch when the pump does not turn off.
Is it one of this HITACHI pump for a well? ..........and AHHHHH ok, just checked the thread is long already and watched the pictures. I guess you are trying to use your pump to pump water into your sandfilter (visible on pic) and then into your pool? I did the same once when my pump on the sandfilter was broken, so i did it this way too.
Is the problem solved already?
if so, happy Songkran from Phuket
mos

On 4/9/2026 at 7:29 AM, emptypockets said:

Assuming the pump is connected to a water tank, has anyone checked that there is actually any water in it?

If the tank goes empty periodically , and then refills over some time, it could explain the problems being experienced.

Or possibly the pump is airlocking at low levels. I understand thats what youve said 👍 😂 but pointing my finger as thats exactly what happened to us.

We have a Hitachi WM-P200GX2 pressure pump in Hua Hin. After trying several plumbers without success, I finally emailed Hitachi Thailand—and they responded in English.

They informed me that my pump model was handled by another company and provided their contact details. After reaching out to them, they recommended a plumber, and the issue was resolved.

The internal parts in your photo looked very similar, so I decided to respond to your post. Please find the contact details below.

I hope this would be of some use to you - if you are contacting them, if possible give a contact number of a Thai speaker - would help a lot.

Came back from a trip last night, standing in the shower, and guess what, no water.

This morning someone new came by and looked at it. He identified the root cause as being a lack of glue on the pipe leading the pump, which was dripping water, and according to him caused air to enter the system, which in turn caused the pump to malfunction.

Does that make sense?

1 hour ago, Na Fan said:

Does that make sense?

yes air in the system would be a problem to fix

On 4/16/2026 at 6:52 AM, Na Fan said:

This morning someone new came by and looked at it. He identified the root cause as being a lack of glue on the pipe leading the pump, which was dripping water, and according to him caused air to enter the system, which in turn caused the pump to malfunction.

So he fixed it and now it works?