Well Pump Options

[chiang mai]

My well is 15 metres deep, water level is typically at 7 metres, my pump will draw to about 11 metres - it's a 3 inch well pipe with a 1 inch pump pickup pipe.

Now I'm hitting 11 metres or very close, I'm thinking of upgrading the pump to get access to the last 4 metres, question is to what, a jet pump? And if so, will a jet pump tie in to my existing 1 inch sprinkler pipe network or do I need something else new?

Finally, once a well has been drilled to 15 metres and 3 inch PVC pipe dropped in, can it be drilled deeper with the blue pipe still in place?.

Thanks in advance for any guidance anyone can give.

[chiang mai]

A second question is, would a booster pump be useful here?

[Crossy]

If the water is more than about 9m below the pump then you'll need either a submersible or jet pump.

A jet would do everything that your existing pump would, but flow tends to be less so a buffer tank and booster would improve flow and pressure at the house.

[chiang mai]

Samson Pumps does a decent line in submersible pumps, Global House stocks them, they come prewired. Not cheap at around 10/14k based on spec but be aware, you need a 4 inch diameter bore, pumps fitting the 3 inch bore don't have very good capacity, grrr!

[zlodnick]

chaing mai,

I had the same problem. My shallow well pump worked great and always had plenty of water. Till this year! In Dec. the water level dropped and when it got down to 9 meters, I was out of water.

A jet pump is the way to go, but like you, I have a 3 inch well. A jet pump needs 2 pipes down the bore hole and with the couplings they are more than 3 inches. They say there is a way of using a jet pump with one pipe down the well, but I havent seen one.

I found a submersable pump that just barely fits my 3 inch bore hole and the wife and I installed it in less than 2 hours. Been 3 months now and Ive run it for over an hour, every other day, no problem.

[kamalabob2]

I've seen the ITC jet pump HTC-D325GX sell for a couple hundred baht more than the Hitachi DT-P300GX in Buriram Province. More powerful was the Hitachi WT-P400GX I also see in stock at a family owned water pump shop that is the repair facility for Hitachi water pumps in Buriram. I've observed some water pump shops include the full set to use in a well and seem to have trained staff who understand the different types of water pumps on offer. 16 meters was the maximum depth mentioned to me for success with a jet pump. I selected and paid for a Franklin Schaeffer submersible water pump for my wife's village home and it has worked fine at a lower depth than would be possible with the surface mounted jet pumps.

[chiang mai]

chaing mai,

I had the same problem. My shallow well pump worked great and always had plenty of water. Till this year! In Dec. the water level dropped and when it got down to 9 meters, I was out of water.

A jet pump is the way to go, but like you, I have a 3 inch well. A jet pump needs 2 pipes down the bore hole and with the couplings they are more than 3 inches. They say there is a way of using a jet pump with one pipe down the well, but I havent seen one.

I found a submersable pump that just barely fits my 3 inch bore hole and the wife and I installed it in less than 2 hours. Been 3 months now and Ive run it for over an hour, every other day, no problem.

It sounds like you installed a 3 inch submersible, can I ask which brand and how was pressure/flow compared to your surface pump? Also, what depth is your submersible at, I'd like to go to 16 metres but am unsure whether the pump will handle.

[zlodnick]

chiang mai,

I dont remember the brand, but think it was a Chineese made. Not too expensive, maybe 5,000 bt.

I went down 24 meters and have plenty of pressure.

The pipe from the pump is 1 inch and then it adapts to 3/4 inch.

[chiang mai]

Perhaps I can ask here who knows of a decent pump shop in Chiang Mai or surrounds, somewhere that stocks submersible well pumps (not regular pumps) ? Global House has a single model that fits my needs but the manufacturer is a complete unknown, even on the internet - a Franklin pump whilst pricey would be ideal except my well is 3 inch, anyone aware of a stockist in CM?

[chiang mai]

I managed to get my well upgraded, the driller will take it down another 6 metres to 20 metres and widen the bore to 4 inch, all done very inexpensively only cost 5k baht.

The question now is, which size of submersible to buy. Depth is a given at 20 metres and I think the Gallons per minute is around 20/25 using my existing surface pump, that makes it look like a 100 litre a minute pump which should allow for some excess capacity, does that sound right to anyone who knows about these things. Note: the pick-up pip[e is one inch as is the bearer pipe that runs around the garden, reducing to half inch at the sprinklers and taps.

[zlodnick]

chiang mai,

You might want to do some research on check valves.

I just assumed my 3 inch submersable had a built in check valve. It doesnt and when I shut the pump off, it drains all the way back down the well.

Google says the check valve should be just above the pump, but Im not about to pull the pump just for that.

[chiang mai]

chiang mai,

You might want to do some research on check valves.

I just assumed my 3 inch submersable had a built in check valve. It doesnt and when I shut the pump off, it drains all the way back down the well.

Google says the check valve should be just above the pump, but Im not about to pull the pump just for that.

Thanks but that is already on my radar.

Do you have any idea what capacity your pump works to in terms of litres or gallons per minute and what depth it is good to? I'm nervous that if I undersize the pump there wont be sufficient flow and if oversized, it may keep cycling and burn out or blow the joints on the sprinkler pipes.

FWIW also, Franklin pumps are available here but expensive in the shops, they have a Bangkok supplier however who will ship them and they are priced very competitively. http://franklinthailand.com/media/Franklin_catalog.pdf

[zlodnick]

Sorry, I dont remember any of the particulars about the pump, I just bought it and put it in.

I think the deeper the better. You shouldnt have any problems there, a submersable can push a long way.

[carlyai]

I used a Luckystar 300 w jet pump. But as my bore is only 3" you have to buy a new jet.

I'll enclose the pics.

My static water level is 12 m

Must allow air to circulate under the pump to help stop the tank from rusting.

I used tape and glue for the screw joins and good quality plastic pipe.

Very quiet pump and works very well.

[chiang mai]

Thanks for taking the time to post all of that, it's food for thought for my next steps.

[carlyai]

One more thing with the lucky star jet pump is the screw adjustment. The instruction manual says to turn it clockwise to start with, but if you turn it fully clockwise (like i did), you won't get pump water output and you may think you have done something wrong. I would say just leave the screw adjustment where it is initially.

After you have water flow then adjust the screw. If the screw is adjusted wrong you end up with air in the system, and when the pump turns on air is in the pump outlet pipe. Adjusting the screw fixes this.

Not too sure what the screw does, but something to do with air charger.

Also, if you pump from a bore to a tank, it's a good idea to have a float switch in the tank to turn the pump on and off.

If you then pump (from another pump) to the house and yard, it's a good idea to have another float switch in the tank so that pump can't come on if the tank has low water.

Example: We went away and let someone else water the garden. The tank ran out of water, so the person watering the garden didnt turn the hose off when no water came out the end of the hose and the pump kept going with no

water.