Yes! Another Water Pump Question.

[Daffy D]

 

I have a Hitachi GX Series WM-P 300GX2 water pump that's been working fine for about 4 years.

Recently when turning any tap on less than about half way the pump will cycle off/on and the water pulsates out of the tap.

Originally when turning on a tap the pump would kick in and there would be a steady  flow of water, now a tap has to be almost fully on before a steady flow of water is achieved.

Having read through previous posts seems that the bladder tank appears to be the problem and a simple drain of the system should fix it.

Unfortunately my pump has one of those Nitrogen filled bladders that can't be fixed just like that. Seems unlikely but is replacing the Nitrogen bladder a job I could do myself, assuming I knew where to get one.

The other option might be to adjust the pressure switch, but I don't know it that would solve the problem, might make things worse.

 

Any constructive thoughts welcome.

 

[carlyai]

I'm sure you've checked it's out of warranty. (some of my pumps say 7 years warranty).
I did have pump problem once, not sure where the prob. was, but, with the pump power off, I manually operated the switch a few times with a screwdriver, then rotated the the pressure switch adjust clockwise and anticlockwise a few times and the problem was fixed.
Probably won't fix your problem, but worth a try.

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[luudee]

In my experience, there are several reasons for this type of failure: 1) Blader tank is leaking (air

or nitrogen). This means that the membrane might have failed, in wich case refilling it will only

provide a temporary fix; 2) If your water is hard, you might have limestone build up in the pressure

switch intake.

 

I don't think #1 can be fixed except by replacing the bladder tank. The second problem might be

fixable by removing the pressure switch and cleaning the intake with a limestone remover, or by

replacing the pressure switch.

 

Good Luck !

rudi

 

[Artisi]

Checking warranty would be a good move, maybe the local pump repair guy (if there is one) has a spare tank you could try to see if this is the problem. 

[sometimewoodworker]

7 hours ago, Daffy D said:

 

I have a Hitachi GX Series WM-P 300GX2 water pump that's been working fine for about 4 years.

Recently when turning any tap on less than about half way the pump will cycle off/on and the water pulsates out of the tap.

Originally when turning on a tap the pump would kick in and there would be a steady  flow of water, now a tap has to be almost fully on before a steady flow of water is achieved.

Having read through previous posts seems that the bladder tank appears to be the problem and a simple drain of the system should fix it.

Unfortunately my pump has one of those Nitrogen filled bladders that can't be fixed just like that. Seems unlikely but is replacing the Nitrogen bladder a job I could do myself, assuming I knew where to get one.

The other option might be to adjust the pressure switch, but I don't know it that would solve the problem, might make things worse.

 

Any constructive thoughts welcome.

 

First, yes you can replace the accumulator (bladder tank) it's an easy 5 minute job. Adjusting the pressure switch is seldom effective but replacement is easy and cheap, so even if it isn't the problem you might as well change it. With our pump it was the flow switch that was the problem, an equally simple job to replace but a little more expensive as the electronics are potted so not serviceable, just replaceable. 

[wayned]

IMHO there is no reason for the accumulator tank to be filled with nitrogen or any other inert gas unless you are pumping hydraulic fluid.

 

I would take out the plug and replace it with a standard air filler nozzle.  If there is any water when you remove the plug then the bladder is leaking and you will have to replace the entire tank, you can not just replace the bladder.

 

Once you put in the air valve pressurize the tank to about 2 PSI below the cut-on pressure.  You can use a standard bicycle pump and air gauge.

[sappersrest]

If your shower works ol and your wc cistern fills ok then the suspect could be the taps exact same thing happened to me newish pump 6 months old, was thinking about taking it back then had a eureka moment.

I remembered some time ago some one had a similar problem on this forum.

Easy removed the mesh on the end of the tap cleaned put it back, works fine.

Sometime the obvious eludes us.

 

[Daffy D]

Thank'yall, Some things for me to consider.

 

I can understand that it's not necessary to have Nitrogen in the bladder tank but I don't want to open the tank and loose the Nitrogen if there is nothing wrong with it, so will leave that as a last resort.

 

 "sappersrest" The problem is with all taps in the house including a garden hose outlet that is right by the pump, so if muck in the system is the problem it must be in the pump it's self.

 

Build up of lime scale seems a good possibility so will dismantle accessible parts of the pump and give them a clean out as necessary.

 

Cheers 

 

 

 

[wayned]

I have a Chinese irrigation pump that I use to pump drinking water from the Ongs that I use to collect rainwater runoff from the roof.  It has a small accumulator tank like yours.  It started cycling on and off continuously and I suspected low pressure but when I pressed the air valve water came out so I definitely have a broken bladder.  Since I only use it for drinking water in the kitchen I just installed a switch on the wall and only turn it on when in use.  It won't correct your problem but the symptoms are the same and I suspect that the bladder is leaking.  Good luck.

[Artisi]

6 hours ago, wayned said:

IMHO there is no reason for the accumulator tank to be filled with nitrogen or any other inert gas unless you are pumping hydraulic fluid.

 

I would take out the plug and replace it with a standard air filler nozzle.  If there is any water when you remove the plug then the bladder is leaking and you will have to replace the entire tank, you can not just replace the bladder.

 

Once you put in the air valve pressurize the tank to about 2 PSI below the cut-on pressure.  You can use a standard bicycle pump and air gauge.

Actually a good comment replacing the gas with air, 10/10.

[Artisi]

2 hours ago, sappersrest said:

If your shower works ol and your wc cistern fills ok then the suspect could be the taps exact same thing happened to me newish pump 6 months old, was thinking about taking it back then had a eureka moment.

I remembered some time ago some one had a similar problem on this forum.

Easy removed the mesh on the end of the tap cleaned put it back, works fine.

Sometime the obvious eludes us.

 

yes, the mesh filters were a pain in the proverbial, I have removed all as the system is 5 years old and all the accumulated bits and pieces from when the initial pipe-work installation would have now cleared, plus haven't seem anything what would indicate it came thru' the town supply.

Don't forget the cistern will have a filter in the incoming line as will the shower (possibly 2) 1 on the heater and 1 on the shower head.

[CGW]

10 hours ago, wayned said:

IMHO there is no reason for the accumulator tank to be filled with nitrogen or any other inert gas unless you are pumping hydraulic fluid.

 

I would take out the plug and replace it with a standard air filler nozzle.  If there is any water when you remove the plug then the bladder is leaking and you will have to replace the entire tank, you can not just replace the bladder.

 

Once you put in the air valve pressurize the tank to about 2 PSI below the cut-on pressure.  You can use a standard bicycle pump and air gauge.

Nitrogen is an inert gas, oxygen heats up when compressed, due to its smaller molecular structure it will weep through the bladder easier than nitrogen, if it comes into contact with flammable substance can explode, not likely in this use, but you can understand why OEM uses it, also one of the reasons why race car tyres are filled with Nitrogen, it is less likely to leak or something along those lines............

Edited March 27, 2017 by CGW

[Crossy]

I'll stick with 78% nitrogen in my tyres and pump bladder.

 

[carlyai]

I'll stick with 78% nitrogen in my tyres and pump bladder.
 

Ahhh...trying to confuse me again. ?

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[Crossy]

Just now, carlyai said:

Ahhh...trying to confuse me again. ?

Sent from my SM-J700F using Tapatalk
 

 

Moi?? Confuse??

[Daffy D]

Finally got fed up with the water from the taps pulsating out and splashing all over the place, so decided it was time to have a look at the pump. 

 

The bladder tank seemed the obvious culprit and surprisingly it is just screwed on, like most car oil filters, so easy enough to take off.

 

After screwing it off I shook the water out and took some photos and checked for a part number to help with getting a replacement. 

 

With noting further to be done at this time I put it all back together and when I tried the taps the pulsating water splashing was gone, it was like it should be with a steady controllable flow of water.

 

So seems like the Nitrogen is still OK just needed to empty out the water from the bladder tank. 

 

Hope this is a permanent fix, at least I'll know what to do next time.

 

Will probably get a spare bladder tank anyway, just in case.

 

[impulse]

34 minutes ago, Daffy D said:

Will probably get a spare bladder tank anyway, just in case.

 

As hooped as you are if the unit fails, you may want to consider having an entire spare if it's an economic possibility.  

 

Murphy's law says it will fail about 3 minutes after the last hardware store in town sells the last of that pump model.  And the spare parts you have won't be the one that craps out...

Edited May 25, 2017 by impulse

[Daffy D]

Yep! I'm very familiar with Mr. Murphy, and over the years have had many dealings with him in various countries.

 

He does seem to get about.

 

 

 

 

[Artisi]

1 hour ago, Daffy D said:

Finally got fed up with the water from the taps pulsating out and splashing all over the place, so decided it was time to have a look at the pump. 

 

The bladder tank seemed the obvious culprit and surprisingly it is just screwed on, like most car oil filters, so easy enough to take off.

 

After screwing it off I shook the water out and took some photos and checked for a part number to help with getting a replacement. 

 

With noting further to be done at this time I put it all back together and when I tried the taps the pulsating water splashing was gone, it was like it should be with a steady controllable flow of water.

 

So seems like the Nitrogen is still OK just needed to empty out the water from the bladder tank. 

 

Hope this is a permanent fix, at least I'll know what to do next time.

 

Will probably get a spare bladder tank anyway, just in case.

 

Cannot see how this is in any way a fix, it's more likely the bladder is faulty, the gas has leaked out and all have done by removing the tank and reinstalling it is to create an temporary air cushion between the water and the bladder. 

[Daffy D]

Sorry if I gave the impression that it was a "FIX"

 

I was surprised as anyone when I put the pressure tank back and it seemed to work OK.

 

Having thought about it a bit I can't really understand why there should be a bladder at all whether it's air or Nitrogen.

 

In the old days you could just mount an upside down air tank somewhere along the water pipe and that would stop any gurgling or pulsating of the water flow. The water in the pipe would pressure the air in the tank and this pressure would change with fluctuating water pressure giving a steady flow at the tap.

 

 

 

Guess this new bladder technology is just getting past me

[Artisi]

I can see it working from what you did, it is now acting like your "upside down" air tank.

Temporary fix until the air is absorbed into the water - and then back to hunting up and down.