Add Additional Water Tank

[Joseph Skoler]

Hi,

I'm hoping someone could guide me.

I have what I believe is an unusual situation.

We have a well (I believe approximately 300' deep) in the Catskill mountains with a 1hp (could be a 1.5) pump about 100' down (I think).

The well head is in a well house with an Amtrol WX-251 62-gallon pressure tank (filters, etc., also) set at 40/60. 1" HDPE then runs to 5 structures (main line branches off at each), with the closest structure about 125' and the farthest about 600'. Two of these structures are infrequently used, seasonal cabins with just 1 full bath. Another structure is also a seasonal cottage with a full bath and kitchen. Another is a year-round small house with full bath and kitchen. Another is a garage/workshop with a bath. In addition, I water the lawn, the garden and occassionally top off a swimming pool.

The pressure drops from about 45 PSI at the second from farthest structure with no water use anywhere to about 25 PSI with a 3/4" valve fully open at that location. And even fluctuates a little (as seen on the pressure gauge I have plumbed in).

I'm hoping to get some expert's thoughts on putting in a second pressure tank (more like a holding tank as it will not have a pressure switch and therefore will not control the well pump) at the central structure (the garage/workshop, which is pushing 400' from the well and central to the 5 structures).

Does this make sense? My goal is to have greater and more consistent pressure and flow volume.

Is there a better way to do this?

Thank you,

Joseph

 

[LLigetfa]

The second tank will affect the pump. Due to friction loss, the second tank will not reach the pump cut-out pressure. After the pump shuts off, the pressure from the first tank will drop as it equalizes to the second tank. That will put the end result pressure closer to the cut-in pressure or depending on use, perhaps even cause the pump to start.

Why not raise the pressure on the entire system? Use a Cycle Stop Valve to keep the pump running and enjoy the higher pressure the system is set to.

 

[Sponsor]

 

[Reach4]

I am not an expert.

I would adjust the pressure switch setting to 55/75 and change the air precharge on your pressure tank to 53. This would be about 5.25 turns clockwise on the 3/8 nut that is on the big spring. It is better to adjust the precharge upward first. You will still get that pressure drop that you see, but it will be a smaller percentage.

Make sure that the pressure is still rising at a fairly good rate as cutoff is reached. You don't want to set the pump to the maximum pressure that the pump can produce. Figure you want the pump to be able to make 5 psi or more than the cutoff pressure.

 

[Joseph Skoler]

Thank you both!

My understand is quite limited, so I'm probably wrong, but my understanding is that part of the problem is the volume capacity at the structures. That is to say, increasing the pressure to 55/75 would not affect how much water can be delivered in a period of time at the point of use. And this amount of water delivered is being limited by diameter and length of pipe between well and point of use.

Would a second storage tank in the well house help?

Please understand, I'd be very happy if solving this problem is as simply as increasing the pressure control switch. But, I'm certainly willing to put another tank somewhere if that's what is necessary.

Thank you!

 

[Joseph Skoler]

Found these very interesting charts. Looks like, for example, a 1" pipe delivery 10 gpm over 500' will lose 15 psi. And, that same 1" pipe with a starting psi of 70 can delivery 53 gpm (losing almost all of its pressure over the same 500'). Am I reading this right?

 

[Reach4]

My understand is quite limited, so I'm probably wrong, but my understanding is that part of the problem is the volume capacity at the structures. That is to say, increasing the pressure to 55/75 would not affect how much water can be delivered in a period of time at the point of use. And this amount of water delivered is being limited by diameter and length of pipe between well and point of use.

If there comes a time where you have a water usage that causes the pump to stay on continuously without the pressure rising, setting the pressure switch higher will not raise that pressure. But higher pressure at the well house will allow water to pass from the well house up the hill and over the distance better.

It's free to try.

Found these very interesting charts. Looks like, for example, a 1" pipe delivery 10 gpm over 500' will lose 15 psi. And, that same 1" pipe with a starting psi of 70 can delivery 53 gpm (losing almost all of its pressure over the same 500'). Am I reading this right?

I think so, although elbows and tees are extra loads that can each be represented by a few extra feet of pipe in the calculations.

One thing to take away is that for a given gpm, the pressure drop is constant. Yes, higher pressure at the far end will cause the flow to increase at the faucet, it will still be worthwhile to raise the pressure.

An extra pressure tank at the well house will increase the minimum run time, which is good, but it will not really improve pressure.

 

[LLigetfa]

That is to say, increasing the pressure to 55/75 would not affect how much water can be delivered in a period of time at the point of use. And this amount of water delivered is being limited by diameter and length of pipe between well and point of use.

All other factors remaining the same, more pressure means more GPM delivered. Raising the pressure will help. Using a CSV with less tank drawdown will help by keeping the pressure higher, sooner, longer. Increasing the pressure will reduce the tank drawdown capacity. It is the pump that makes pressure.

 

[Valveman]

Water volume and pressure come from the pump, not the pressure tank. Adding another pressure tank is increasing the demand on the pump, and the pressure will stay low for longer periods of time. Like Reach says, try turning up the pressure switch. If your pump can build more pressure, it will push more water through longer pipes. If your pump won't build more pressure and supply the volume you need, a larger pump is what you need, not another pressure tank.