****UPDATE****

 

Spent a fruitful evening on YouTube and have the matter sorted for the time being.  Learned that the 2-liter accumulator (Hey, there's a new word!) can lose pressure over time.

 

 

Videos from Myanmar and Indonesia show how to install a car-tire inflation valve to the end cap, but local models already have the re-pressuriser valve included.

 

This morning removed and cleaned the accumulator.  Tested (Stick a chopstick in it!) and found the diaphram was up against the top cap.  It was serving no useful purpose at all.  Used the bicycle floor pump to repressurize to 1 bar, and reinstalled.

 

Seems to be working properly now.  The ticking noise that I (cityboy with city tap water) thought was the pump pumping, was actually the pump switching on and off.  Now maintaining pressure in the accumulator, pump switches on and hums, then switches off.  And the water-hammer banging has ceased.

 

We'll keep this one until the fall, then replace with a Hitachi or Mitsubishi constant pressure model without adding a separate pressure tank.  This one will go out by the spare water tank and will set up piping to liquidate the fruit trees.

 

If the accumulator leaks pressure, we can easily replace for around 200 baht.

 

https://www.lazada.co.th//products/i4963400338-s20887836648.html

 

Thanks to all posters for their comments and contributions.

 

 

 

Good news that!

On 1/12/2024 at 4:40 PM, ross163103 said:

Here's some pics of the system. I built a manifold in order to have all options available; I can feed my pump directly from moo ban system, fill my underground tank, have pump suck from underground tank, or bypass pump and use pressure from moo ban system--which is not very much but usable in an emergency.

 

First pipe right side of mainfold: water in to system which can feed pump directly and/or fill my underground tank depending on what valves are opened/closed.

Second pipe moving to the left; a bypass around pump system in case pump fails.

Third pipe is fill for underground tank

Fourth pipe is suction from unerground tank to pump inlet

As you can see on the opposite side is the pump outlet feeding my system and teeing off to fill the pressure tank.

 

I used unions in case something goes wrong with valves or piping, I can easily remove the whole manifold without cutting/gluing pipes. I've never had an issue with the unions except when I was gone and my wife had to get the pump changed by a Thai water/pump guy. He couldn't understand the system or why I used unions; he wanted to cut everything out and glue in new pipes. I told my wife to just wait till I got back, no problem. The unions are rated for the pressure I have on the outlet side.

 

As far as the tank price, it was quite a few years ago but I want to say somewhere around 6k-7k baht. It's got a rubber bladder inside that holds pressurised air on one side and water on the other. Also the tank has a mount on top that fit my pump directly, no mods needed.

Any other questions feel free to ask.

 

How do you bleed air from the accumulator tank?

19 hours ago, Spacer said:

How do you bleed air from the accumulator tank?

Most, if not all accumulator tanks I've seen do not have any way to bleed the tank. They have a rubber bladder inside the tank and a schrader valve on the bladder side that allows it to be pressured up.  When you first get the accumulator there's either no pressure on the bladder and it needs to be pressurized, or it already has pressure on it, probably the latter. When pressurized the bladder is taking up all the space in the tank, then as water pressure in your system overcomes the bladder pressure it fills with water, there shouldn't be any air in the water system side of the tank. Something similar to the attached file but not exactly, no  poppet valve in the bottom. Those are hydraulic accumulators, just an example. I have seen accumulators made with large diameter PVC with no bladder, the problem is you take a chance on air getting into the system because of no bladder separating the two mediums. 

15 minutes ago, ross163103 said:

Most, if not all accumulator tanks I've seen do not have any way to bleed the tank. They have a rubber bladder inside the tank and a schrader valve on the bladder side that allows it to be pressured up.  When you first get the accumulator there's either no pressure on the bladder and it needs to be pressurized, or it already has pressure on it, probably the latter. When pressurized the bladder is taking up all the space in the tank, then as water pressure in your system overcomes the bladder pressure it fills with water, there shouldn't be any air in the water system side of the tank. Something similar to the attached file but not exactly, no  poppet valve in the bottom. Those are hydraulic accumulators, just an example. I have seen accumulators made with large diameter PVC with no bladder, the problem is you take a chance on air getting into the system because of no bladder separating the two mediums. 

 

When you install the accumulator just add three valves and you can easily drain it. Or, it the installation is complete, you can just unscrew it and let it drain.