If you are near Buriram you can take it to Buriram Ruangsangthai and they can sort out the pump while you shop. They sell a lot of these pumps and have parts in stock for repair.


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If the non return/check valve has failed or is stuck open due to dirt then maybe the weight of the water in the tank causes enough pressure to overcome the p1ss poor city pressure causing the water to go back through the pump and causes cycling ??

I don’t know, just a guess as I had a similar issue which corrected itself after I had drained the pump and tank.

ok the message I got back was that lid I indicated in the last photo , has no spring or valve inside it ;-( ....

ok the message I got back was that lid I indicated in the last photo , has no spring or valve inside it ;-( ....

Bummer. I think your fixers need to take a pic of the pump and go to the nearest shop fixing and selling Mitsubishi pumps. There is usually a repair shop around that may not look all that flash from the street.

Better still, take the pump with them. If the nearest local shop can't help they will usually point you to a shop that can.
Usually they test and fix the pump on the spot.

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And if you do that^  The easiest way to remove/re-install the pump is to unbolt the clamps at the in/out ports.  That way you don't have to cut PVC.  When re-install, be sure the seals are correctly oriented before tighten.

9 minutes ago, bankruatsteve said:

And if you do that^  The easiest way to remove/re-install the pump is to unbolt the clamps at the in/out ports.  That way you don't have to cut PVC.  When re-install, be sure the seals are correctly oriented before tighten.

Don't forget to buy a couple of the gaskets that go under the ports, they are so cheap you might as well replace them.

1 hour ago, carlyai said:

Bummer. I think your fixers need to take a pic of the pump and go to the nearest shop fixing and selling Mitsubishi pumps. There is usually a repair shop around that may not look all that flash from the street.

Yes bummer because without it the pump will never hold any pressure. These non return valves are in similar location for most pumps of this style and sometimes have the spring removed depending on suction arrangement.

 

The op should close outlet valve run the pump up to pressure then close and open inlet valve to prove back feeding faulty non return. Up to now the fault locating logic is a bit mashed.

Mitsubishi non return plunger with removable seal...

 

 

 

Try to put in a backflow preventer - sometimes the village water pressure is so low - and you might have a hose in your garden connected BEFORE the pump - that the pump actually cuts in pumping water back out into your pipes that feed it - if it works it’s a very cheap few hundred baht fix.

 

 

 

 

on my way home this weekend to deal with , first step will be to add non return valves on the house & pump , it has to be the problem ....keep you posted ...

What was the outcome cdmtdm ?

Always handy to know for future reference .

still not resolved ....non return valves did not fix it , really unsure on the next move , water supply runs under the house slab , no access if it is a cracked pipe .... no signs anywhere of wet patches forming , checked all toilets & hws...it could be in the shower mixer taps as I know they were connected from pvc to copper on the actual mixer ...I guess I can remove the tiles in the vicinity of the tap , open the wall & see ....difficult problem.... the pump will cycle off and hold for about a minute , then come on & run for 5-10 seconds ....

Have you checked the stop valves that are (maybe) under the cabinet for the sinks?  Better yet check all stop valves even if they are normally open.  I have had to replace several low quality valves that had corroded and just crumbled when I turned the valve.  (which required a run to the main cut-off).  If you need to replace, make sure SS or brass.  Anyway... the first thing they will do is have a tiny leak in the valve itself.

On 5/17/2019 at 1:28 PM, CGW said:

Are you sure it has no bladder/diaphragm believe all these pumps have one built in?

I have a Mitsubishi 350 watt and there is a small tank about 6 inches long and 4 inches in diameter,

 

Mine has been cycling like crazy for quite a while as I have a cracked pipe under ground somewhere. It sounds like it has the death watch beetle and I have replaced it with a Vavo of similar power. I have had to replace some of the plumbing as the Vavo has an input like the Mitsu but the outlet is 90 deg to one side instead of straight through.

 

I took the time to raise the pump onto a metal table so I don't have to scrabble on the ground. I put a metal shut off valve each side so that I can isolate the pump. Both metal valves leak and I got 2 different ones today. I had to tighten up all the joints on the Vavo and I still have a couple of leaks. I got some gaskets that I will fit when I replace the leaking valves.

 

To replace the valves means I have to cut the old ones out and lengthen the pipe work. It looks messy but if I can get the Mitsu repaired I will have to replumb it all again anyway.

 

That will be on hold for several days because coming out of the hardware shop I fell off the curb on my left shoulder and hand. It hurts like buggery. I managed to drive home but my wife had to help me get my shirt off, Luckily the shop staff saw it happen and helped me up and took me to my pickup truck across the road.

ok after a long drawn out process , problem resolved .... the discharge line from the pump to the house passed through at 90 degree a short section of concrete before entering the house underground , the elbow had not been glued properly & the pipe was literally moving in & out of the elbow until the leak got so bad & the dirt had washed away enough it then blew the elbow off .... thanks for all the tips & suggestions fellas ...

On 5/17/2019 at 12:04 PM, sometimewoodworker said:

On 5/17/2019 at 11:39 AM, cdmtdm said:

I cannot accept that a pipe must be broken under the house as it stopped cycling for 5 days !!!

Either you have a joint that is failing, an outlet that is leaking or a cracked pipe 

So my post number 4 was spot on????

 

But anyway good job finally finding and fixing the problem.

3 hours ago, sometimewoodworker said:

So my post number 4 was spot on????

 

But anyway good job finally finding and fixing the problem.

Will whoever fixed the pipe leak please come over and do mine. I live in Nakhon Nowhere.

42 minutes ago, billd766 said:

Will whoever fixed the pipe leak please come over and do mine. I live in Nakhon Nowhere.

I happen to know where that is.  I'll be there in a few... Uhm, not sure.  Cheers mate. 

3 hours ago, bankruatsteve said:

I happen to know where that is.  I'll be there in a few... Uhm, not sure.  Cheers mate. 

The problem I have is that the pipes were laid some 14 years ago and I cannot remember where they were laid. Since then some areas were covered in concrete.

I dug down and found what I thought was the leak, cut and capped the pipe after laying a new pipe overground but it is still leaking a bit which causes the water pump to cycle.

Old age, creaky bones etc cause me a problem, in that I cannot kneel down and dig it out so easily as I have a problem getting up again.

I am working on a fix for it, but I have to wait to find a Thai with the time to do it for me.

We changed to surface/external pipe about 15 years ago and no issues since and use higher pressure Grundfos pumps.

4 hours ago, lopburi3 said:

We changed to surface/external pipe about 15 years ago and no issues since and use higher pressure Grundfos pumps.

I can understand that but one pipe splits and one leg goes into the hose under the concrete and is split again with that leg going to what is now an old store house. That leg is mostly underground and is shut off as the trees cracked the pipe so I simply cut and capped it. 

 

The leg where my current leak is runs from the junction after the big filter, under the concrete floor where my workshop is and where we park the car up to my MIL old house.

 

I replumbed the water feed and bypassed the big filter which doesn't filter very much and the water flow is much higher now. 

 

It looks a bit of a mishmash but it works.

 

I am going up to Global house next week to look at inline filters as with the old filter it costs a lot to change the carbon twice a year.