Water pump

[nevets]

Chas, the pressure switch monitors the water pressure at the tap and when the tap turns on the pressure will drop , the pump starts and water flows fast . When the tap is closed the pressure will go up until it reaches the setting on the switch , the pump will stop until the tap is opened again ,and everything starts over ( another cycle).

[nevets]

ps. if the pump runs on to long after the tap is off then the switch needs to be altered to + or - until a short over run is acheivd. If the pump is osolating turning on and off fast when the tap is off then the switch needs to be set again untill it stops efecting the pump , to start and stop .
These pumps are made for on off dutty and will run hot sometimes this is ok.

[Nereus]

The technician did mention that I should put a stop valve on the outflow end, but since the standpipe is about two feet higher than the pump, there is a lot of water in the pipe that stays there when the pump is off. I dont see the point of an outflow stop valve.
Nereus, the pump does not seem to overheat at all. I have felt it after using it for a half hour or so and all parts of it seem to have stayed cool.

Also, what does the pressure switch relate to if not to the water pressure either intake or outflow? (You seem to know an lot about these things!!)

I didnt mention that the pump is called ( I have the booklet out now which I didnt before) an "Electric Well Pump" ( LSW111EA. . whatever that means) and there is a diagram along with it that shows the feedback that you describe. But if the inflow pipe has a stop valve to keep the water IN the pipe, it wont go back to the canal, it will just go into the pump again. . with some force I would imagine. .when I restrict the flow in some way. Wont water pressure IN be just as damaging? (It would be like connecting intake and outflow together like a closed system!)

PRSCT. ..how long have you had your garden pump anyway?

Maybe there are different kinds of pumps here? Mine has something called an "Air Charger Assembly" that I had to screw on. The pumps I looked at around here ( three or four houses) dont have anything resembling this "air charger" Nereus. . would this make a difference?

Happy New Year, Chas. If your pump is running about 15 seconds on and then off for a similar amount of time, you will probably not have any problem with it. It is when they cut in and out rapidly, like the flashers on a car, that will cause overheating.

Returning some of the water to the suction will not cause any damage to the pump. It would need to be arranged so that the amount of flow can be regulated, to balance the amount the sprinkler is using. A simple ball type valve, or one with a wheel on it would work. Or you could fit a tee piece on the standpipe with the valve and a short hose to divert the water back into the canal.

Water cannot be compressed, so if the pump pushes the water when there is no flow, or less flow through your sprinkler than the rated output of the pump, then the pressure rises and operates the pressure switch. Air can be compressed, and a lot of those small pumps, (it is actually called a "shallow well pump") use an air chamber to provide a "cushion" that allows a volume of water to accumulate with the air space providing the pressure for some of the time. Rather like a coil spring that compresses, and then pushes the water out while the pump is in the off part of the cycle.

The other pumps that you have looked at will probably be mounted on a small tank that is part of the pump unit. These also work on the same principle and sometimes have an automatic valve in the system that ensures an air charge. If the tank loose`es its air charge for some reason, and becomes "flooded" then the pump may run continuously and not build up enough pressure to operate the switch. The usual fix in that case is to unplug the pump and drain the water out of the tank, and then just start it up again.

Hope that you do not get a headache reading all this, just sit down and have a beer with it!

[Chas]

Happy New Year Nereus, Nevets, SPcst and all!

And thanks for the input here.

There is a round tank at the bottom of this pump and a round cover. . .and it looks. . . from all that you say. . .like it will be OK as I have it set up. Right now it is just the hose and nozzle, but I plan to work in a sprinkler system too and that should help as there will always be outflow when I turn it on.

This is almost like a course in pump mechanics here! Maybe my luck with pumps will change?

Now if I could only repair the German made pump that I bought new from Home Pro last year it would be great. I made the big mistake of not trying it out right away and when it came time to do so and it wouldnt work, it was beyond the return date for Home Pro. Had a guy look at it. Switch was faulty he direct wired it. . still doesnt work. It sits in the box in my garage and haunts me every time I come across it!

[PeteC]

Maybe we should get into sprinkler systems now? I had one installed about a month ago and you may encounter a new set of problems. Namely, the 2-3 sprinkler heads nearest your pump are going to use up most of the pressure, and those down the line will have nothing but large drips coming out. Problem solved by installing sprinkler heads with a small control valve right beneath it allowing you to turn down the volume on those close to the pump while leaving those far away wide open. You can balance your system this way.

Concerning an example of length, sprinkler heads and pump....I have a medium power pump like you and sprinkler heads spaced about 1.5 meters apart. Total length is about 35 meters. I've found that with my pump, that's about the maximum you can go and still get an adequate flow out of all the sprinklers, with those nearest to the pump regulated as described above. Pete

[Nereus]

Maybe we should get into sprinkler systems now? I had one installed about a month ago and you may encounter a new set of problems. Namely, the 2-3 sprinkler heads nearest your pump are going to use up most of the pressure, and those down the line will have nothing but large drips coming out. Problem solved by installing sprinkler heads with a small control valve right beneath it allowing you to turn down the volume on those close to the pump while leaving those far away wide open. You can balance your system this way.

Concerning an example of length, sprinkler heads and pump....I have a medium power pump like you and sprinkler heads spaced about 1.5 meters apart. Total length is about 35 meters. I've found that with my pump, that's about the maximum you can go and still get an adequate flow out of all the sprinklers, with those nearest to the pump regulated as described above. Pete

I have an automatic sprinkler system that I ended up installing myself, as could not find anybody that had a clue about it. Your problem is probably more to do with the size of the piping installed, especially the main distribution from the pump. The ring main part of mine is 1.5 inch pvc, and most of the sprinkler zones are 1 inch (25mm), PE pipe, some 1 inch pvc.

Again, it all goes back to designing the system based on the output of the sprinklers, the friction head, especially the number of bends / elbows, etc, before you spec the size of the pump. I get good coverage with the pop-ups, but they are limited to 4 per zone. I also used a couple of sections of fixed spray lines, and the only problem I have with them is blocking up caused by the calcium salts in the bore water. I have recently changed it over to Government water supply, so hopefully that problem will go away. It also has a rain sensor in the system, which inhibits the program timer when it rains.

Another problem that you will run up against here is trying to work out how much water is needed, and when. It varies of course, depending on the time of the year and just what you are watering. But the main thing is to apply the water either before sun-up, or late in the evening. The loss through evaporation if applied during the day, can be up around 50 to 60%. The Thais will tell you that you MUST apply the water during the hottest part of the day!

[PeteC]

Mine is just a manual system. The in-ground pipe is 1.5 inch and the pipe to the sprinklers is 3/4 inch. My system is raised with each head on a pipe about 1/2 meter high with those green whirlybird type sprinklers on top. It's right beneath these heads I installed the little orange regulator valve which is simply something you turn which progressively blocks the opening. I think they only cost about 20 baht each.

I've got 9 of these manual stations going around the perimeter of the entire place, the purpose mainly for all the bushes, flowers and palms planted there, with the added advantage that the whirlybird heads also cover an area of grass about 2 square meters. The rest of the grass is still a manual process.

The pump I'm using came with the house and was really meant to be the house pump, but I changed things. It is adequate though given the 9 separate stations (running only one at a time) with the longest being about 30-35 meters from tap to last sprinkler. Pete

[Wanderlust]

As there is a wealth of water pump knowledge gathered on this thread, I have a question; if the water supplying the pump dries up, should all pumps have a cut off to prevent them running dry? I have lived in 3 different houses in the Hua Hin area, including the one we bought nearly a year ago, and most areas here suffer water cut offs, but in every house i have lived in the pump does not cut off when the water runs out. Is there some sort of mechanism/setting I should look for to alter, or is there something i can have installed to fix this? Or is it a question of buying another pump? The pump we have is a Mitsubishi WP 205Q2 if that means anything!

[Nereus]

As there is a wealth of water pump knowledge gathered on this thread, I have a question; if the water supplying the pump dries up, should all pumps have a cut off to prevent them running dry? I have lived in 3 different houses in the Hua Hin area, including the one we bought nearly a year ago, and most areas here suffer water cut offs, but in every house i have lived in the pump does not cut off when the water runs out. Is there some sort of mechanism/setting I should look for to alter, or is there something i can have installed to fix this? Or is it a question of buying another pump? The pump we have is a Mitsubishi WP 205Q2 if that means anything!

Most pumps will not stand being run without water for any length of time.
If your supply is via a tank of some description, (it should be), then a float switch that opens if the water drops below a certain level, and wired into the pumps electrical supply, would probably be the best way to avoid the problem. Where you could buy such a switch I have no idea, and it may take a bit of ingenuity to make up a simple float and arm to operate a commercial type limit switch.

[Wanderlust]

OK, thanks very much for that info Nereus. **adds 'float switch' to never ending list of things that need doing....

[PeteC]

OK, thanks very much for that info Nereus. **adds 'float switch' to never ending list of things that need doing....

Here's an example of this WL. Even though it states "sump pump" I think the theory is the same per the drawings. Nereus please advise if I'm way off on this. I've seen these type of float switches here in the big Home stores. Pete

http://www.plumbingworld.com/alarmsandf ... tches.html

[Nereus]

OK, thanks very much for that info Nereus. **adds 'float switch' to never ending list of things that need doing....

Here's an example of this WL. Even though it states "sump pump" I think the theory is the same per the drawings. Nereus please advise if I'm way off on this. I've seen these type of float switches here in the big Home stores. Pete

http://www.plumbingworld.com/alarmsandf ... tches.html

Yes, that will do it Pete. I have used a similar type to the first unit shown. They are completely sealed and it is just a matter of finding the correct position to "tether" it. If they have 3 wires in them, they can be connected up to operate either way. Which "Home" store have you seen this in?

[PeteC]

Good question as I don't remember. It was during one of numerous browsing sessions. It was either Home Pro or Global in Rayong. I'll keep my eyes open next time there.

I think a call to a local plumber may do it as well. When I had my bore dug they set up an above ground holding tank and installed an electric float sensor that works opposite to what we're talking about here. In other words, when the tank begins to empty and the teathered float goes past ? degrees vertical, it turns on the submersible pump down in the bore to fill the tank again, then turns it off once the float is horizontal again. The Thai company who did the work bought the sensor float locally. Pete

[Nereus]

Good question as I don't remember. It was during one of numerous browsing sessions. It was either Home Pro or Global in Rayong. I'll keep my eyes open next time there.

The Thai company who did the work bought the sensor float locally. Pete

That`s handy to know. Like a lot of things in Thailand, the goods are available, just a matter of finding out where!