Calculating Pump Water Output.

[farmerjo]

14 minutes ago, carlyai said:

Hi farmerjo, yes I do.

Just set up the 300W Hitachi with a 25 mm pipe down 7m and pump for an hour?




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Unless you have access to some thing like a 1 or 2" petrol pump that you can vary the speed.

[Cake Monster]

OP,

 

Your problem may not be the actual pump, but the Electric supply to it.

You say the output drops from first switching on to when you take your measurements.

This maybe because the pump is pulling too much power ( amps ) when switched on and then settles down 

 

Try checking the voltage when first switched on and again when running 

Also the same for amperage 

 

If the voltage is low and the Amperage high when running  try increasing the size of your Electric cable from the pump to the controller.

 

 

[carlyai]

Sounds like a plan, it may even work so well you'll leave it installed [emoji2]

Not too sure about that. It's our old pump from the Pattaya house. Must be 7 years old. Renter said the pump blew up and they put in a new Hitachi at my expense. I dropped the unit off the other day at the pump shop. Picked up yesterday and all working fine, so they say at a cost of B 250.


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[Fruit Trader]

8 minutes ago, carlyai said:

Not too sure about that. It's our old pump from the Pattaya house. Must be 7 years old. Renter said the pump blew up and they put in a new Hitachi at my expense. I dropped the unit off the other day at the pump shop. Picked up yesterday and all working fine, so they say at a cost of B 250.


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You could of course ..

 

 

[carlyai]

OP,
 
Your problem may not be the actual pump, but the Electric supply to it.
You say the output drops from first switching on to when you take your measurements.
This maybe because the pump is pulling too much power ( amps ) when switched on and then settles down 
 
Try checking the voltage when first switched on and again when running 
Also the same for amperage 
 
If the voltage is low and the Amperage high when running  try increasing the size of your Electric cable from the pump to the controller.
 
 

Thanks for that. I think most of the power cables are OK, except for the underground Al part: sigh. Power is about 210 volts. I think the fall off in performance is due to the broken threaded sections near the venturi allowing air to enter.

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[carlyai]

You could of course ..
 

 

I used to practise a lot of that mechanical lifting motion when I was younger. Anyway, the solution will be on hand.

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[Cake Monster]

If its the broken section around the venturi, you may be able to use some " EPO PUTTY " from the hardware store that will set hard around the crack and seal it 

[Fruit Trader]

14 minutes ago, carlyai said:

I used to practise a lot of that mechanical lifting motion when I was younger. Anyway, the solution will be on hand.

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If you are to continue with the single pipe drop and above ground jet then ..

The threaded connections on the jet  might be a pain because most Thai male adaptors have parallel threads and require half a roll of PTFE tape. A smear of silicone gasket over the PTFE will stop the vacuum leaks.

Also, you might consider 3 plastic barrel unions on the jet to make removal easy.

[carlyai]

If you are to continue with the single pipe drop and above ground jet then ..
The threaded connections on the jet  might be a pain because most Thai male adaptors have parallel threads and require half a roll of PTFE tape. A smear of silicone gasket over the PTFE will stop the vacuum leaks. Also, you might consider 3 plastic barrel unions on the jet to make removal easy.

Hi and thanks. My farmer guys screwed it all too tight and there is a crack in the thread, plus the other joint. These pvc blue plastic thread connections into anything else are a real pain. When you do a couple every 6 months, it's judging how much white tape to apply and how tight to screw it up just before it breaks or it will leak. All hit and miss.

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[Artisi]

56 minutes ago, Fruit Trader said:

You could of course ..

 

 

Not completely trouble free, but cheap to run ?

[bankruatsteve]

Better yet is not needing a pump at all.  My uncle had a farm that had artesian aquifers below.  They stuck a pipe into it with some kind of control head where you just lift the lever and the best water ever comes gushing out.

[sandyf]

I have a Hitachi 300w parallel jet pump. The pump is the same for both the SJ and PJ and I bought the PJ purely on the basis the pipe assembly was far easier than that for the SJ. The SJ is mainly intended for very small bores, the Hitachi is down to 2 inch. This was the step in the assembly that put me off.

2. Expand the end of the provided 1-inch PVC pipe (suction pipe) about 50 mm by holding it over the fire as shown in the figure of step 1.

 

The instructions for SJ make a bit of an issue on sealing with silicone against leakage so I would suggest that if the OP did not put the pipe together himself then the assembly may be suspect. As far as I can make out the jet assembly is at the bottom of the pipe in both cases.

 

Our pump was put in over 4 years ago and runs without problem. It supplies 3 dwellings and all 3 can run at the same time without any significant loss in flow.

 

[carlyai]

I have a Hitachi 300w parallel jet pump. The pump is the same for both the SJ and PJ and I bought the PJ purely on the basis the pipe assembly was far easier than that for the SJ. The SJ is mainly intended for very small bores, the Hitachi is down to 2 inch. This was the step in the assembly that put me off.
2. Expand the end of the provided 1-inch PVC pipe (suction pipe) about 50 mm by holding it over the fire as shown in the figure of step 1.
 
The instructions for SJ make a bit of an issue on sealing with silicone against leakage so I would suggest that if the OP did not put the pipe together himself then the assembly may be suspect. As far as I can make out the jet assembly is at the bottom of the pipe in both cases.
 
Our pump was put in over 4 years ago and runs without problem. It supplies 3 dwellings and all 3 can run at the same time without any significant loss in flow.
 

Double jet arrangement was working well, only problem was sand in the footer valve.

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[Artisi]

13 minutes ago, carlyai said:

Double jet arrangement was working well, only problem was sand in the footer valve.

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Is /was the foot valve sitting on the bottom of the well / borehole? 

If it's a foot or two clear of the bottom how are you collecting sand, is there any sand discharged in the pumped flow?

PS. I sent you a private message today. 

[sandyf]

12 hours ago, carlyai said:

Double jet arrangement was working well, only problem was sand in the footer valve.

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That is a fairly common problem with various arrangements. Prior to the Hitachi we had an old reciprocating pump, the valve was on a flexible and my late father in law just used to pull it out and give it a clean. A bit more difficult these days.

[carlyai]

Is /was the foot valve sitting on the bottom of the well / borehole? 
If it's a foot or two clear of the bottom how are you collecting sand, is there any sand discharged in the pumped flow?
PS. I sent you a private message today. 

I read your message thanks.
The footer valve was about 1 m from the bottom of the well. The sand is very fine like powder, like crushed dirt. So I'd water the garden in the morning and the next morning no head of water for the pump to prime. I'd squirt the hose down to fill up the bore pipe but it wouldn't fill. Then rock the pipes up and down to work the footer valve and then I could fill the bore pipe and all OK.
But it kept happening fairly regularly, but not every day.
I have a similar pump and set up about 100 m away and was not having the same problems.
I was 98% convinced it was the valve sticking open, but when I bought the pipes up to have a look the footer valve was closed. It wasn't until the 3rd time I pulled the bore pipes up that I thought it might be something to do with the jet assembly and decided to experiment with a 1 pipe simpler arrangement.
Now I'm 100% sure it was the footer valve sticking open and that the dual pipe system with the jet at the bottom was working well.
Eventually this bore pump will be set up for irrigation and aquaponics use, with storage tank, solenoids etc.

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[farmerjo]

So where are you at now Carl?

Did you try the Hitachi or just going back to old system.

[Crossy]

If it continues to lose prime add a Tee to the DOWN pipe near the pump, put a tap on it.

 

When you need to prime attach the hose to the tap, open said tap and turn on the water, once the gurgling stops (you'll need to open the pump discharge if it has a tap on it) both up and down pipes should be full and your pump will start pumping immediately you power it up. Note if the pump doesnt have a check valve on it's jet output you may need to add one.

 

I have a similar arrangement to prime our khlong suction. Madam occasionally fails to check the khlong level before powering on the pump resulting in lost prime. It takes 30 seconds to re-fill the pipes and get the pump pumping again, even Wifey can do it.

 

[bankruatsteve]

I think filling the bore hole pipe with water is unnecessary.  There is a water table some meters down or there is not and filling the bore hole pipe will have no effect on pump performance.  When you had it out, did you check for sand/debris in the venturi funnel?

[carlyai]

So where are you at now Carl?
Did you try the Hitachi or just going back to old system.

Hi farmerjo, yes Mitsubishi 250 W (sorry wrong pump name before) all set up. Just waiting on my back to come good to continue, probably tomorrow.

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[carlyai]

If it continues to lose prime add a Tee to the DOWN pipe near the pump, put a tap on it.
 
When you need to prime attach the hose to the tap, open said tap and turn on the water, once the gurgling stops (you'll need to open the pump discharge if it has a tap on it) both up and down pipes should be full and your pump will start pumping immediately you power it up. Note if the pump doesnt have a check valve on it's jet output you may need to add one.
 
I have a similar arrangement to prime our khlong suction. Madam occasionally fails to check the khlong level before powering on the pump resulting in lost prime. It takes 30 seconds to re-fill the pipes and get the pump pumping again, even Wifey can do it.
 

Hi Crossy, 100% sure it was the footer valve sticking open due to fine sand.

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[carlyai]

I think filling the bore hole pipe with water is unnecessary.  There is a water table some meters down or there is not and filling the bore hole pipe will have no effect on pump performance.  When you had it out, did you check for sand/debris in the venturi funnel?

Hi bankruatsteve, maybe misled you. I take off the pump primer cap and fill the reservoir. If the footer valve is open, the water just drains through. When it's closed the bore pipe and reservoir/header tank will fill up. I don't actually fill up the bore hole. Sorry for the vagueness.

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[Crossy]

4 hours ago, carlyai said:

If the footer valve is open, the water just drains through.

Yeah, that's why I was suggesting attaching some means of blasting water down the pipe, should be enough to overcome the (slight?) leak at the check valve until the pump actually starts pumping.

[bankruatsteve]

But...but...  If the system is full of water and everything tight at the pump, how is the water going to drain out even if the foot valve is open?  Is there a valve at the pump output that gets closed when the pump is off?

[Artisi]

7 minutes ago, bankruatsteve said:

But...but...  If the system is full of water and everything tight at the pump, how is the water going to drain out even if the foot valve is open?  Is there a valve at the pump output that gets closed when the pump is off?

So long as it's sealing. 

[carlyai]

I set up my Mitsubishi EP205QS pump for an hour. The discharge rate at the tap was 120 L/hr.

The bore hole is 12 m deep and ID of 75mm or 3".

The water level in the bore before turning on the pump was 5.93m and after an hour with the pump on dropped to 5.87 m or 60mm.

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[Artisi]

4 minutes ago, carlyai said:

I set up my Mitsubishi EP205QS pump for an hour. The discharge rate at the tap was 120 L/hr.

The bore hole is 12 m deep and ID of 75mm or 3".

The water level in the bore before turning on the pump was 5.93m and after an hour with the pump on dropped to 5.87 m or 60mm.

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5.93 - - 5.87??? 

But a good result anyway. 

[carlyai]

So long as it's sealing. 

Think I'll go back to teaching Chinese calculus, easier than these pumps.
Now I will probably get caught out here again, but to me it seems if you have 7m height 30 cm diameter pipe full of water 2m say into the bore water the pressure from the water in the pipe is greater therefore if the foot valve is open the water will drain out.
Did I hear '<deleted>'?

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[bankruatsteve]

It's like putting a straw in a glass of water and with your thumb on top can pull it out with water intact.  The pressure inside is less than outside.  The weight (pressure) of the water only becomes a factor when the "straw" is 8m or more.

[carlyai]

5.93 - - 5.87??? 
But a good result anyway. 

Ok, I'll put it all back together with the original system.
I tried to put a flexible pipe on the pump output but it kept blowing the ring fastener off, and the strong men weren't around so installed rigid pipe again.
I'll try and install quick connect screw connectors in the pressure and suction lines to make it easier to disconnect the pump from the pipes.


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