Pipework Leaks - Pump Problems

[JAS21]

So we are here for 3-months in our new house..its out of it years warranty now. The builders repaired a water leak in the garden whilst we were in the UK…on the blue plastic pipe.

Anyway we still have a problem. I want to replace all the blue plastic pipe that I can with something more flexible. Last leak caused by a tree root they said.

So what is available please in Thailand

How do you connect from blue pipe to new flexible pipe. I going to run the supply from the meter (well just inside our land) to the tank, above ground along the bottom of the wall. Its well shaded.

Also if I recall there are at least two qualities if nrv’s what is the best one called. Does anyone run two in series in supply from meter.

Also the company managed to run the pump dry at some stage..at least once.. so its not as good as it should be…whats the best pump to buy. I’ll change it when we come here for good at the end of the year. It’s a WP255.. they also messed with the cutin/cutout.pressure switch. Anyone know where to get instructions to re-set it up. Cutin/cutout seems to close now.

Thanks

[penzman]

Gor for a known brand (like Mitsubishi) if you replace the pump. I' ve tried getting an english manual online for ours (Fujika) but it was only available in Japanese and Thai.

If the new flex pipe is slightly transparaent, it may grow algae on the inside if running above ground. I have a transparent garden hose that always sits in the shade and has turned green after a while.

[lopburi3]

Can not answer the flex pipe question as do not use it on home side of meter. There are several grades of the blue plastic pipe so you may have had the cheap thin wall type.

The water pump sounds like a small home unit that if you keep a large spread in the cut in/off you may have only a dribble of water, then strong type problem which is not good if you have volume controlled water heaters. We used to run a WP455 type pump (which is about 30PSI) but changed to a Grundfos water cooled jet type pump several years ago and like it very much as have 65PSI and hotel like pressure from water heaters now. The only down side is a half second delay when tap is turned on (as do not use a pressure tank) but pump is relatively quiet and you make use of the cooling heat.

[JAS21]

Can not answer the flex pipe question as do not use it on home side of meter. There are several grades of the blue plastic pipe so you may have had the cheap thin wall type.

The water pump sounds like a small home unit that if you keep a large spread in the cut in/off you may have only a dribble of water, then strong type problem which is not good if you have volume controlled water heaters. We used to run a WP455 type pump (which is about 30PSI) but changed to a Grundfos water cooled jet type pump several years ago and like it very much as have 65PSI and hotel like pressure from water heaters now. The only down side is a half second delay when tap is turned on (as do not use a pressure tank) but pump is relatively quiet and you make use of the cooling heat.

[chownah]

I don't believe that a tree root caused the leak. No one but you is having this problem with tree roots and blue pipe so I suggest that the pipe is not the problem. It could be that they didn't put any glue on the joints of the pipe and this allowed a tree root to enter the system and cause the problem but this is incompetence from the pipe layer and should not be blamed on the tree.

A centrifigul water pump can run dry with no ill effects. I suppose that if it ran for several hours it could overheat but if it seems to pump ok then it probably *is* ok and I wouldn't worry about it.

I've got a pump almost like yours...I think mine is the next size down but not sure. The pressure switch on mine is not adjustable and if they "adjusted" it then it should probably be replaced. If it is the rapid cycling of the pump that makes you think the pressure switch needs "adjusting" I would suggest that the tank does not have enough air and bleeding out the water and then restarting the pump will solve the problem. The pressure switch went out on my pump after about 3 years of use and I took it in to replace it. I hired my uncle to re-install it and its guaranteed that he didn't look at the manual. It cycled too fast so I got out the manual and sure enough it told how to cope with this problem by bleeding and restarting....go check your manual and see what it says....what?...you threw away your manual?....oh my...then go to a store that sells new ones and ask them if you can borrow a copy for photocopying.

[JAS21]

Can not answer the flex pipe question as do not use it on home side of meter. There are several grades of the blue plastic pipe so you may have had the cheap thin wall type.

The water pump sounds like a small home unit that if you keep a large spread in the cut in/off you may have only a dribble of water, then strong type problem which is not good if you have volume controlled water heaters. We used to run a WP455 type pump (which is about 30PSI) but changed to a Grundfos water cooled jet type pump several years ago and like it very much as have 65PSI and hotel like pressure from water heaters now. The only down side is a half second delay when tap is turned on (as do not use a pressure tank) but pump is relatively quiet and you make use of the cooling heat.

Thanks

Yes it is a small home unit..there is usually enough mains pressure to use the shower upstairs. The pump feeds into the circuit after the nrv from the mains. But when showering or running a tap it cuts in and out every few seconds. I'd like to set the cutin lower and the cut ut higher so that when a tap is on full it runs all the time...

I'll look around for some coloured hose...

[Gary A]

Chownah is correct. The switch is not normally adjustable. Your pump is simply waterlogged. It has lost the air cushion and needs to be drained. If there is no plug to take out of your tank take the bolts out of the flange the outlet is hooked to and let all the water drain out. When the water is completely drained the pump will work like new.

[JAS21]

I don't believe that a tree root caused the leak. No one but you is having this problem with tree roots and blue pipe so I suggest that the pipe is not the problem. It could be that they didn't put any glue on the joints of the pipe and this allowed a tree root to enter the system and cause the problem but this is incompetence from the pipe layer and should not be blamed on the tree.

A centrifigul water pump can run dry with no ill effects. I suppose that if it ran for several hours it could overheat but if it seems to pump ok then it probably *is* ok and I wouldn't worry about it.

I've got a pump almost like yours...I think mine is the next size down but not sure. The pressure switch on mine is not adjustable and if they "adjusted" it then it should probably be replaced. If it is the rapid cycling of the pump that makes you think the pressure switch needs "adjusting" I would suggest that the tank does not have enough air and bleeding out the water and then restarting the pump will solve the problem. The pressure switch went out on my pump after about 3 years of use and I took it in to replace it. I hired my uncle to re-install it and its guaranteed that he didn't look at the manual. It cycled too fast so I got out the manual and sure enough it told how to cope with this problem by bleeding and restarting....go check your manual and see what it says....what?...you threw away your manual?....oh my...then go to a store that sells new ones and ask them if you can borrow a copy for photocopying.

Thank you young man.

Yes you are correct about the glue I suspect...We have had a few leaks from un-glued pipes..as have a number of other houses. I'm so 'pissed off' that I'm going to repipe a smuch external as I can.

We have just got here and am now loosing about 1CuM/day..just found out yesterday by checking meter. As its BH cannot even ask company where previous leak was.

Centrifugal pumps can run dry..some will pick up on the glands and some wont..if its single stage..and I guess that it is then may get away with it..however I found it hot...they forgot to switch it off when repairing a leak..just shut the valve. It was never the same after that.

Air lock is not the problem..but thanks anyway..

A mister tossaphon is the site foreman...appley named........

Never got a manual..might try the web site

Edited July 9, 2006 by John45

[chownah]

I'm not sure that what I described is called "air lock". Gary A's post above describes what I vaguely remember causing the problem and the solution. The base of the pump is a tank and that tank should have a certain amount of air in it and I think that your's doesn't have enough...at least the rapid cycling *can* be caused by that.

Good luck,

Chownah

Edited July 9, 2006 by chownah

[Gary A]

A good pressure switch normally has two springs. One for the high pressure and one for the low pressure. All the pumps I have seen here including mine have one spring. It's very possible that your handyman has tampered with the switch and that could cause erratic performance. If the pump is telegraphing (on, off, on, off) it certainly won't hurt to try to increase the spring pressure to see what happens. Increasing the tension by screwing the nut towards the switch should cause the pump to pump to higher pressure.

[JAS21]

A good pressure switch normally has two springs. One for the high pressure and one for the low pressure. All the pumps I have seen here including mine have one spring. It's very possible that your handyman has tampered with the switch and that could cause erratic performance. If the pump is telegraphing (on, off, on, off) it certainly won't hurt to try to increase the spring pressure to see what happens. Increasing the tension by screwing the nut towards the switch should cause the pump to pump to higher pressure.

Thank you

Yes he did do something on the pressure switch. I looked yesderday and couldnt see how to adjust. I have e-mailed Mitsubishi asking for information on the pump. There appears to be nothing on the web.

I guess that the bottom chamber has a diaphram with air presure on one side. Think its sealed for life. Do you know what the bottom 'drain, if thats what it is, is for.

I would just like to understand how it works. Do you know anyone who has a csa of the pump and MI if possible..MI is manufactures instructions.

Thank you

[Crossy]

This website, explains how the resevoir works and how to ensure it has the correct amount of air in it, too little air will cause short-cycling, an effect simlar to what you describe:-

http://www.inspect-ny.com/water/watertank.htm

The site talks about well pumps, but the principle is identical, also tells you what the bottom drain is for (could be useful for your problem).

[lopburi3]

These pumps should have automatic air control and not need any adjustments (famous last words). It would be fit into a threaded access to the tank. I did have to clean one time after about 10 years but normally believe it is rather trouble free. The pressure switch can be accessed after taking the cover off (power off first - several wires will access it) and there should be a small screw (at top if I recall correctly with a lock nut) This is normally epoxyed into position and spare units can be bought preset for the pump model as they do get pitted after extended use and need replacing. I have also found a keen interest among the 'plumbers' to fiddle with it.

[chownah]

A good pressure switch normally has two springs. One for the high pressure and one for the low pressure. All the pumps I have seen here including mine have one spring. It's very possible that your handyman has tampered with the switch and that could cause erratic performance. If the pump is telegraphing (on, off, on, off) it certainly won't hurt to try to increase the spring pressure to see what happens. Increasing the tension by screwing the nut towards the switch should cause the pump to pump to higher pressure.

Thank you

Yes he did do something on the pressure switch. I looked yesderday and couldnt see how to adjust. I have e-mailed Mitsubishi asking for information on the pump. There appears to be nothing on the web.

I guess that the bottom chamber has a diaphram with air presure on one side. Think its sealed for life. Do you know what the bottom 'drain, if thats what it is, is for.

I would just like to understand how it works. Do you know anyone who has a csa of the pump and MI if possible..MI is manufactures instructions.

Thank you

I think that there is no diaphragm in the bottom but you're getting the idea. Here's how it works. The upper portion of the bottom (I'll call it a "tank") has air on the top and water on the bottom. The water stays on the bottom because its heavier than the air...like when you fill a glass of water the water goes to the bottom....no diaphragm is necessary to maintain this. When the tank is full the air is squeezed to the same pressure as the upper limit of your water pressure and it is compressed into a realtively small volume. As you slowly draw water out at a tap for instance the air above the water in the tank exerts pressure on the water below and this creates the pressure that forces the water out the tap...as you do this the air expands and eventually after you have removed enough water the air expands to the point where the pressure in the air (and the water) falls below the turn-on pressure and the pressure switch turns the pump motor on. The pump forces water into the tank which tends to fill up the tank and compress the air in the top of the tank and thus the pressure slowly increases as the air gets compressed into a smaller volume...until...the pressure reaches the turn-off pressure of the pressure switch at which point the pressure switch cuts the power to the pump motor and it stops. There is a one way valve that keeps the water from bleeding back through the motor. If you run the water fast enough you can remove it from the tank as fast as the pump supplies it to the tank and the pump will run continuously since the volume of water in the tank remains constant and it does not compress the air and thus the cut off point for your pressure switch is not reached...until...you reduce the rate of water withdrawal (or shut the water off) at which time the rate you are removing the water is less than the rate that the pump is putting water into the tank and thus the volume of water in the tank will increase and squeeze the air until it reaches the cutoff pressure.....etc. not going to proof read hope I said it right.

[Gary A]

The better pumps have an air bladder and they should last for at least five years or more with no problems. As far as the cheaper pumps the automatic air injector is far from foolproof. I have to regularly drain my tank and I'm not smart enough to adjust the air injector. There is also a check valve or maybe you want to call it a one way valve. It allows the water to go into the pump and stops it from flowing back out when the pump stops running. If water is leaking back through this built in valve it will cause the pump to telegraph. That's not a major problem either because you can easily put an extra check valve (one way) in the line coming into the pump. I think the brass check valve I put in cost about 300 baht. In any case the extra check valve will not bother anything.

[penzman]

I've unscrewed the air cylinder on our Fujika pump and the water that leaked out of it was rusty with small particles of corroded metal. I doubt these small models have a bladder, maybe a diaphragm, if so it's not very airtight anymore.

[JAS21]

A good pressure switch normally has two springs. One for the high pressure and one for the low pressure. All the pumps I have seen here including mine have one spring. It's very possible that your handyman has tampered with the switch and that could cause erratic performance. If the pump is telegraphing (on, off, on, off) it certainly won't hurt to try to increase the spring pressure to see what happens. Increasing the tension by screwing the nut towards the switch should cause the pump to pump to higher pressure.

Thank you

Yes he did do something on the pressure switch. I looked yesderday and couldnt see how to adjust. I have e-mailed Mitsubishi asking for information on the pump. There appears to be nothing on the web.

I guess that the bottom chamber has a diaphram with air presure on one side. Think its sealed for life. Do you know what the bottom 'drain, if thats what it is, is for.

I would just like to understand how it works. Do you know anyone who has a csa of the pump and MI if possible..MI is manufactures instructions.

Thank you

I think that there is no diaphragm in the bottom but you're getting the idea. Here's how it works. The upper portion of the bottom (I'll call it a "tank") has air on the top and water on the bottom. The water stays on the bottom because its heavier than the air...like when you fill a glass of water the water goes to the bottom....no diaphragm is necessary to maintain this. When the tank is full the air is squeezed to the same pressure as the upper limit of your water pressure and it is compressed into a realtively small volume. As you slowly draw water out at a tap for instance the air above the water in the tank exerts pressure on the water below and this creates the pressure that forces the water out the tap...as you do this the air expands and eventually after you have removed enough water the air expands to the point where the pressure in the air (and the water) falls below the turn-on pressure and the pressure switch turns the pump motor on. The pump forces water into the tank which tends to fill up the tank and compress the air in the top of the tank and thus the pressure slowly increases as the air gets compressed into a smaller volume...until...the pressure reaches the turn-off pressure of the pressure switch at which point the pressure switch cuts the power to the pump motor and it stops. There is a one way valve that keeps the water from bleeding back through the motor. If you run the water fast enough you can remove it from the tank as fast as the pump supplies it to the tank and the pump will run continuously since the volume of water in the tank remains constant and it does not compress the air and thus the cut off point for your pressure switch is not reached...until...you reduce the rate of water withdrawal (or shut the water off) at which time the rate you are removing the water is less than the rate that the pump is putting water into the tank and thus the volume of water in the tank will increase and squeeze the air until it reaches the cutoff pressure.....etc. not going to proof read hope I said it right.

OK Thanks...now a little info

My pump is utilised as a system pressure booster if required. It sits below the water tank. Mains pressure will fill this tank or supply the house as required. The pump discharge tees into the house supply line via a nrv. The mains water supply has its own nrv.

I now probably understand the pump.

It has a spring loaded suction valve. Its probably a single stage (its shouldn’t need to be multi stage) centrifugal pump which discharges directly into the vessel below. I see no need for the pump itself to have its own discharge nrv.

The pressure switch monitors the tank pressure. In my case there is a nrv on the tank outlet, but it could very well have a normal discharge valve. The nrv would stop the pump reverse rotating if the suction valve were to fail. Not doing the motor any good when it starts and also overfilling the tank.

I believe my pump to be worn, most likely the impellor glands. It may also have excessive clearances to the casing.

The suction nrv is ok and the spring is there.

With the mains water supply shut off, pump tank empty and then starting the pump the system pressure slowly rises. Switching pump off and unscrewing the drain results in pressurised water ejecting! until the tank is empty.

Shutting the mains water supply, electrically isolating the pump, closing the suction valve and opening a tap in the garden results in the pressure decaying slowly. The pump tank pretty well empties.

With the mains water supply on and using a garden hose..starting the pump results in a slightly greater flow and pressure. However with pump on or off putting your finger over the hose end can result in the water squirting about the same distance.

Before it was cooked there was a big difference in the pressure/flow……..

The pump still cuts in and out frequently…I believe it to be ****ed

Does anyone know if you can buy just the pump. Is it much cheaper that the 5000/6000 Baht for a complete new unit.

[JAS21]

I've unscrewed the air cylinder on our Fujika pump and the water that leaked out of it was rusty with small particles of corroded metal. I doubt these small models have a bladder, maybe a diaphragm, if so it's not very airtight anymore.

Is the pump simular in construction the the Mitsubishi WP255 that I have. If so am surprised that it didn't flush itself out when in use. Guess its just a bit of corrosion. You could run the pump and pressurise the tank...isolate and open the drain wide...wear goggles! that should clear it out

[chownah]

John45,

If you find a reputable place that repairs these pumps they no doubt can check it out for a nominal fee (maybe for free) and tell you what it would cost to fix it.....

Chownah

[JAS21]

John45,

If you find a reputable place that repairs these pumps they no doubt can check it out for a nominal fee (maybe for free) and tell you what it would cost to fix it.....

Chownah

Thanks

Went to Home Pro today to do a little shopping. talked to the guy there..you can buy just the pump and of course the pressure switch.

They gave me Mitsibishi phone number in BK. he said the pump was guaranteed for 5 years...Not if somebody run it dry for hours I dont think..anyway I will phone them tomorrow and post what happens..thanks