Can anyone tell me if these pumps are maintenance free or require periodic maintenance? The instructions I have are in Thai and no matter how hard I try Google is letting me down on trying to find them in English.
It just dawned on me yesterday that all things mechanical usually require some sort of maintenance surely...???
We have been using the pump for a little over 12 months now.
Maintenance free to my knowledge, at least Mitsu and Hitachi. After several years if they start to lose pumping power there is a way to increase pressure. Best for a repairman to do that.
The only other thing I can think of is there should be a top that unscrews on the top somewhere to open to purge air if too much gets into the system.
Those are the only things I can think of. Pete
EDIT: Pump life for Mitsu and Hitachi is around 7-8 years with everyday use per my experience. This doesn't mean they stop working, it means they lose pumping power and no more adjustments can be made. Best to just replace it rather than screw around more.....IMO.
Governments are instituted among Men, deriving their just powers from the consent of the governed. Source
prcscct wrote:Maintenance free to my knowledge, at least Mitsu and Hitachi. After several years if they start to lose pumping power there is a way to increase pressure. Best for a repairman to do that.
The only other thing I can think of is there should be a top that unscrews on the top somewhere to open to purge air if too much gets into the system.
Those are the only things I can think of. Pete
EDIT: Pump life for Mitsu and Hitachi is around 7-8 years with everyday use per my experience. This doesn't mean they stop working, it means they lose pumping power and no more adjustments can be made. Best to just replace it rather than screw around more.....IMO.
Thanks a lot for that, and the jao nai says thanks as well. Here's a pint for you!
I had my Mitsubishi pump for 5 years before it gave up the ghost. Tried to fix it, but all the bolts were corroded and just sheared off, so had to replace it.
Now I routinely spray WD 40 or equvilant, every month over all the screws and metal areas, to keep it rust free. Also, the black plastic end cap on the motor is hel by two long bolts. Take this off and spray inside the rotor whilst the pump is running.
All this will make it rust and corrosion free, and you will get a couple of years more out of it.
A lot of corrosion in these pumps is caused by leakage, accelerated by the big cover creating a “steam bath”.
After replacing a leaking rubber diaphragm a couple of times, the unit that controls the pressure cut off. The older guy at Big Kiang told me that these pumps were not good for above ground tanks, but were designed to suck from below ground.
It makes sense, as to have a constant head of water, of anything up to 4,000 psi can not be good for the pump.
Schoolboy maths/physics from my hazy past says 2,000 liters = 400 gallons (approx), 1 gallon = 10 pounds, hence 4,000 psi. Even if the maths are not completely correct it is still a high pressure.
I have now treplaned a 1.25 inch hole in the top of the tank to take a 1 inch internal diameter pipe, the pump now sucks from the tank and the impending next diaphragm replacement which I already have the spare for as the drip had started, has disappeared.
Cost for pipe modification, about 200 Baht, neighbors recent pump replcement (4 years old) from Big Kiang 8,000 Baht including fitting. He now also has the new pump feeding from the top of the tank.
chaspul wrote:It makes sense, as to have a constant head of water, of anything up to 4,000 psi can not be good for the pump.
It is ridiculous statements like this that show up your complete ignorance of technical knowledge, just like your crap about air conditioning.
Do you have ANY idea the thickness a tank would have to be to withstand 4,000 psi?
There is am old saying: "keep your mouth shut and be thought a fool, or open it and remove all doubt". Fits yoiu perfectly.
May you be in heaven half an hour before the devil know`s you`re dead!
chaspul wrote:It makes sense, as to have a constant head of water, of anything up to 4,000 psi can not be good for the pump.
It is ridiculous statements like this that show up your complete ignorance of technical knowledge, just like your crap about air conditioning.
Do you have ANY idea the thickness a tank would have to be to withstand 4,000 psi?
There is am old saying: "keep your mouth shut and be thought a fool, or open it and remove all doubt". Fits yoiu perfectly.
chaspul wrote:It makes sense, as to have a constant head of water, of anything up to 4,000 psi can not be good for the pump.
It is ridiculous statements like this that show up your complete ignorance of technical knowledge, just like your crap about air conditioning.
Do you have ANY idea the thickness a tank would have to be to withstand 4,000 psi?
There is am old saying: "keep your mouth shut and be thought a fool, or open it and remove all doubt". Fits yoiu perfectly.
Bieudron Hydroelectric Power Station in the Swiss Alps has a head of 6,130 feet and manages 2,994 psi so you would need some tank to get 4,000!
chaspul wrote:It makes sense, as to have a constant head of water, of anything up to 4,000 psi can not be good for the pump.
It is ridiculous statements like this that show up your complete ignorance of technical knowledge, just like your crap about air conditioning.
Do you have ANY idea the thickness a tank would have to be to withstand 4,000 psi?
There is am old saying: "keep your mouth shut and be thought a fool, or open it and remove all doubt". Fits yoiu perfectly.
Bieudron Hydroelectric Power Station in the Swiss Alps has a head of 6,130 feet and manages 2,994 psi so you would need some tank to get 4,000!
I believe those oscillating foo foo valves are a bugger too...
ALL pumps, centrifugal or positive displacement (piston type), will have improved efficiency drawing off a flooded suction head. In fact, some industrial positive displacement pumps use a “supercharging” pump in the suction line for this reason.
However, it depends on the application of the pump and system. The advice given by Big Kiang is correct for these small “house” pumps; they are in fact called a “shallow
well pump”. The increase in efficiency with a flooded suction in this application is negligible.
The problem is that SOME of them will allow water from a higher pressure, be it a tank or the mains supply, to run through the pump and “flood” the small pressure tank.
Mitsubishi do not appear to have this problem, where as ITC pumps do. This leads to there being too much water and very little air pressure. The result is the rapid cycling on and off of the unit when water is drawn off. (ie: open a tap)
To overcome this, the easiest way is to unplug the pump and drain the tank by removing the small threaded plug provided for this purpose near the bottom of the pressure tank. Once the tank has drained just replace the threaded plug and restart the pump. The prime should not have been lost and the system will pump up to the correct balance of air pressure to water volume.
The pumps are “self priming” and the plug referred to by Pete is for filling the housing of the pump with water the first time it is used. It should not be necessary to bleed any air out of this plug, as the pump has a valve, usually called a “snifter valve” for this purpose. Sometimes this valve may get a bit of dirt in it and need cleaning.
As posted above, spraying the unit with WD 40 may help prolong its life, but I would not recommend removing the fan cover and spraying inside while the motor is running. If the manufacturer thought that the cover was causing a steam bath then I am sure they would have provided different ventilation.
May you be in heaven half an hour before the devil know`s you`re dead!
I've got an Hitachi GX series (photo below) for the house and it doesn't have any pressure tank at the bottom like the Mistu we have for the garden does. Just today our in ground tank (2000L) ran dry as a main break Friday night that we didn't know about and tank wasn't refilling. After things back to normal with tank filing above the intake pipe to the pump, the pump wouldn't run. I had to unscrew that top plug and prime it to get pressure and to get a pump start up. While I was in there the mechanism has at least two big warning decals stating 'DO NOT REMOVE", one is on the pressure switch and the other on something else. Hitachi doesn't want you messing with some things and I know fiddling with the pressure switch will void any warranty. Pete
WM-P350GX.jpg (14.43 KiB) Viewed 3547 times
Governments are instituted among Men, deriving their just powers from the consent of the governed. Source
Nereus
Whats technical about basic Physics?
2,000 litres of water weigh 4,409 pounds, therefore, this weight is distributed accros the tank area, this being a cylinder which is the strongest container, it can be reletively thin walled.
If you open a 1 inch tap the full weight of water will try to exit this tank at high pressure, decreasing as the level and weight falls. Remember the experiment, punching holes in a 2 litre pop bottle and measuring the distance the water traveled as it emptied?
Therefore, a 1 inch pipe to the pump, which is not actualy 1 in sqare but leave phi out of this, would have the full weight of water pressurising this pipe.
I did say my maths was approximate.
Please don't pass remarks on things you don't or can't grasp, don't snipe at everyone, lead a peaceful life.
My General engineering experience far surpasses yours, although I did like the bit on shallow well pumps, this seems to endorse my post. Yes you may be the expert on pumps, but experts can be proved wrong and look foolish.
As far as hydro goes, the geny inlet pipe has a much larger inlet pipe area thus reducing psi.
Not too into hydro dynamics concerning Dams, but think it is something to do with mass and height.
"The pressure exerted by a static fluid depends only upon the depth of the fluid, the density of the fluid, and the acceleration of gravity."
"The fluid pressure at a given depth does not depend upon the total mass or total volume of the liquid." http://hyperphysics.phy-astr.gsu.edu/hbase/pflu.html
chaspul wrote:Nereus
Whats technical about basic Physics?
2,000 litres of water weigh 4,409 pounds, therefore, this weight is distributed accros the tank area, this being a cylinder which is the strongest container, it can be reletively thin walled.
If you open a 1 inch tap the full weight of water will try to exit this tank at high pressure, decreasing as the level and weight falls. Remember the experiment, punching holes in a 2 litre pop bottle and measuring the distance the water traveled as it emptied?
Therefore, a 1 inch pipe to the pump, which is not actualy 1 in sqare but leave phi out of this, would have the full weight of water pressurising this pipe.
I did say my maths was approximate
Please don't pass remarks on things you don't or can't grasp, don't snipe at everyone, lead a peaceful life.
My General engineering experience far surpasses yours, although I did like the bit on shallow well pumps, this seems to endorse my post. Yes you may be the expert on pumps, but experts can be proved wrong and look foolish.
As far as hydro goes, the geny inlet pipe has a much larger inlet pipe area thus reducing psi.
Not too into hydro dynamics concerning Dams, but think it is something to do with mass and height.
Maybe Terry can tell us a little more?
Chas
Sorry but your basic physics and maths are wrong.
The pressure on a sub at 2,700 metres is approx 4,000 psi!
Please recheck your maths
"'The two most important days in your life are the day you are born and the day you find out why." - Mark Twain
chapul wrote:Please don't pass remarks on things you don't or can't grasp, don't snipe at everyone, lead a peaceful life.
I am not going to lower myself to your kindergarten level to to explain basic phyics to the likes of you. You proved previously that you are just full of brown waste matter.
May you be in heaven half an hour before the devil know`s you`re dead!
