will larger diameter drop pipe help my shallow well

Rick.a · Oct 7, 2009

I have a shallow well (15 ft to water level) and a 1/2 hp jet pump. Drop pipe is 1" poly and pipe up to house is 3/4" poly and goes uphill about 30 ft on a 130 ft run. All works fine. Pump takes 75 seconds to fill pressure tank (5.8 gal draw down) from 30 to 50 psi.

I am replacing the drop pipe with PVC to make it easier to pull it each fall (seasonal only-Massachusetts) by using a poly compression fitting instead of fighting with the poly stuck on the barb each time.

Question: Would there be any gain for me to move to 1 1/4" PVC for the drop pipe, or is my limiting factor the 3/4" poly to the house and I should not bother upsizing the suction pipe?

thanks,

NHmaster · Oct 7, 2009

rick.a said:
I have a shallow well (15 ft to water level) and a 1/2 hp jet pump. Drop pipe is 1" poly and pipe up to house is 3/4" poly and goes uphill about 30 ft on a 130 ft run. All works fine. Pump takes 75 seconds to fill pressure tank (5.8 gal draw down) from 30 to 50 psi.

I am replacing the drop pipe with PVC to make it easier to pull it each fall (seasonal only-Massachusetts) by using a poly compression fitting instead of fighting with the poly stuck on the barb each time.

Question: Would there be any gain for me to move to 1 1/4" PVC for the drop pipe, or is my limiting factor the 3/4" poly to the house and I should not bother upsizing the suction pipe?

thanks,

don't know what brand pump yu have but Goulds says right up front not to decrease the drop to anything less than 1 1/4" pipe. Then you should most definitely change the run to the house to 1" minimum. I would use PPE

Sponsor · 2022-01-29T12:20:58-0800

Gary Slusser · Oct 7, 2009

rick.a said:
I have a shallow well (15 ft to water level) and a 1/2 hp jet pump. Drop pipe is 1" poly and pipe up to house is 3/4" poly and goes uphill about 30 ft on a 130 ft run. All works fine. Pump takes 75 seconds to fill pressure tank (5.8 gal draw down) from 30 to 50 psi.

I am replacing the drop pipe with PVC to make it easier to pull it each fall (seasonal only-Massachusetts) by using a poly compression fitting instead of fighting with the poly stuck on the barb each time.

Question: Would there be any gain for me to move to 1 1/4" PVC for the drop pipe, or is my limiting factor the 3/4" poly to the house and I should not bother upsizing the suction pipe?

thanks,

If you aren't going to use 1.25" for everything, there is no sense in going from 1" to 1.25" only up to the surface. If you need more water at the house, you should replace the 3/4" with 1" and use the 1" drop pipe. You could use a union to disconnect. I wouldn't want to rely on a compression fitting supporting any weight going down my well, or for suction. An o-ring sealed union would be better IMO.

NHmaster · Oct 7, 2009

This is pasted right out of Goulds installation manual should there be any confusion. RedJacket and F&W have similar instructions.

Suction Piping The suction pipe should be at least as large as the pump suction, typically 1Â¼". Use of smaller pipe increases friction loss and increases effective suction lift. This will reduce flow and pressure. On offsets over 50' we recommend using pipe larger than the pump suction. This will reduce friction loss and improve performance. Hazardous pressure can cause personal injury or property damage. WARNING

Masterpumpman · Oct 8, 2009

NHMaster is right!

Most pump manufactures recommend not using less than the pump input size and if the suction distance is long they recommend using one size larger. There is a considerable friction loss in the 3/4" line to the home as well.

If I was installing the pump I would probably use 1-1/4" PVC on the suction and 1" on the discharge. I don't like unions on any suction lines because it increases the possibility of three additional suction leaks. . . however since you will be removing the pump annually, I would probably install PVC unions on both the input and output lines.

Porky, MGWC
"NGWA" Master Ground Water Certified

Rick.a · Oct 8, 2009

Hi All,

I agree with all of these responses. But...I have noticed that a union connection, although much stronger than a compression, has an interior constriction with a fairly small diameter. Isn't this going to hurt the suction?

I will go with 1 1/4 pvc for the suction, but will the union hurt it's performance much? Is there any other type of connection without an internal constriction that is easy to separate?.

I cannot upgrade the 3/4" to the house YET as this requires a very long difficult dig up a hill with lots of roots in the way. By the way it IS a Goulds pump.

Gary Slusser · Oct 8, 2009

nhmaster said:
This is pasted right out of Goulds installation manual should there be any confusion. RedJacket and F&W have similar instructions.

Suction Piping The suction pipe should be at least as large as the pump suction, typically 1Â¼". Use of smaller pipe increases friction loss and increases effective suction lift. This will reduce flow and pressure. On offsets over 50' we recommend using pipe larger than the pump suction. This will reduce friction loss and improve performance. Hazardous pressure can cause personal injury or property damage. WARNING

Yes I know, and his system will work just fine with 1" and much better with 1" to the house instead of the 3/4" he has now.

Rick.a · Oct 8, 2009

Hi Gary,
I guess that you have confirmed that the limiting factor in my system is the 3/4" pipe to the house and that increasing the drop pipe diameter will not change the performance overall.

My main concern for changing anything at all is to simplify pulling the drop pipe in the fall. The pump stays in the well house all winter since I drain it.

I could use a LITTLE more GPM flow but not much since now the only continuous flow is the shower and with this fairly low performance system the pump just barely keeps up with it so the pump does NOT cycle during showering which is good for it.

So what do you think about the constriction in the union fitting? Is it a concern? Or should I go up to 1 1/4 just to get a bigger union?

NHmaster · Oct 8, 2009

Rick, yes, decreasing the drop size will most definately effect pump performance. Manufacturers put that kind of information in their installation manuals for a reason. It's not a suggestion. Reduction here will reduce the pumps drawing performance on the suction side. If the inlet on your pump is 1 1/4" than go with 1 1/4" the cost in pipe is negledgable

NHmaster · Oct 8, 2009

Gary Slusser said:
Yes I know, and his system will work just fine with 1" and much better with 1" to the house instead of the 3/4" he has now.

If you know, then why are you telling him to reduce the suction line to 1" ?
The manufacturer says 1" are you saying that you know better than the people that make the pump?

Gary Slusser · Oct 8, 2009

rick.a said:
Hi Gary,
I guess that you have confirmed that the limiting factor in my system is the 3/4" pipe to the house and that increasing the drop pipe diameter will not change the performance overall.

My main concern for changing anything at all is to simplify pulling the drop pipe in the fall. The pump stays in the well house all winter since I drain it.

I could use a LITTLE more GPM flow but not much since now the only continuous flow is the shower and with this fairly low performance system the pump just barely keeps up with it so the pump does NOT cycle during showering which is good for it.

So what do you think about the constriction in the union fitting? Is it a concern? Or should I go up to 1 1/4 just to get a bigger union?

A 1" union has no restriction, it is full open like a ball valve.

So add a union and leave the rest as is until you need more flow and then increase the 3/4" to 1".

nhmister, "If you know, then why are you telling him to reduce the suction line to 1" ?
The manufacturer says 1" are you saying that you know better than the people that make the pump? "

He has 1" dop pipe, I'm not telling him to install 1". I said increase the 3/4" to 1". And the pump manufacturers say 1.25", not 1".

Thatguy · Oct 8, 2009

figure your losses

http://www.engineeringtoolbox.com/pe-pipe-pressure-loss-d_619.html
Cold water in plastic pipe,
ID = 0.5", 4.8 GPM, 5 ft/sec, 8.8 psi drop per 100'

http://www.engineeringtoolbox.com/pvc-pipes-equivalent-length-fittings-d_801.html
90 elbow 0.5" ID, 1.5'
gatevalve 0.5" ID, 0.3'
tee-flow branch 0.5" ID, 4'

will larger diameter drop pipe help my shallow well

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