Help with water Pressure

[Skooterj]

I don't know if there are any plumbers/Geothermal guys on here, but I have a question. I have an open loop GeoThermal system. And I love it. I also have a constant pressure, 1 HP pump at the bottom of a 140 foot well. When the Geo system is on, I have just a minor drop in domestic pressure to my shower, but not enough to worry about. However, if the Geo is on and I try to water my lawn, especially if using more than one sprinkler at a time, I get a dramatic drop in pressure. I want to know how to properly plumb the output from the Geo unit back into the hose bibs so it makes up this lost pressure. ie, the red pipe on the drawings. I know I can't restrict the flow of the Geo, but I'm sure there must be a proper way to plumb this setup.
Thanks

 

[larry_g]

What is your history with this? Has the system ever worked differently and this is a new problem or are you new to this house and just figuring out the how things work?

lg
no neat sig line

 

[Skooterj]

I built the house 4 years ago. It has always worked this way. I never personally measured the flow of the pump, or how much flow the Geo uses. But according to the well drilling company, my well can deliver 25 GPM, and the Geo Manual says it needs 6 GPM. I turned up the pressure on the pump to 70 PSI, but didn't realize I needed to also increase the pressure of the pressure tank. I have a Grundfos CU-301 controller that says at 70 PSI, the tank needs to be at 49 PSI. I did that yesterday. I haven't tried the sprinklers yet, so it may have fixed the pressure problem. The showers seem about the same. But even if that did fix the pressure problem, I still feel like I am wasting water by not reusing the Geo 'waste' to water my yard.

 

[Showkey]

I built the house 4 years ago. It has always worked this way. I never personally measured the flow of the pump, or how much flow the Geo uses. But according to the well drilling company, my well can deliver 25 GPM, and the Geo Manual says it needs 6 GPM. I turned up the pressure on the pump to 70 PSI, but didn't realize I needed to also increase the pressure of the pressure tank. I have a Grundfos CU-301 controller that says at 70 PSI, the tank needs to be at 49 PSI. I did that yesterday. I haven't tried the sprinklers yet, so it may have fixed the pressure problem. The showers seem about the same. But even if that did fix the pressure problem, I still feel like I am wasting water by not reusing the Geo 'waste' to water my yard.

Wasting water………..That’s an under statement !!!!

Like the see the documentation and theory on how pumping and wasting 6 GPM is an economical way to heat or cool.

Also, this a permitted system ? There are many locations where this is specifically prohibited.

 

[Skooterj]

Okay, wasting water is kind of miss statement. It isn't contaminated at all. I pump it out of the ground, then drop it right back into the water system where it flows back into the aquifer. And it is extremely economical compared to electric or propane heating, or traditional air conditioning. Open loop systems are the most efficient Geothermal systems. And yes, it is permitted. My electric bills are on par with what I used at my old house and I had to pay for water and sewage on top of that there. And I have about 2000 more square feet.

 

[jlv03]

Why not store the output of the GEO in a tank and put a pump on that to run the sprinkler?

 

[TractorJeff]

I knew another guy in Indiana about 15 years ago that had a "waste" the water Geo system also. I believe his was a low volume like the OP's?

 

[larry_g]

Okay, wasting water is kind of miss statement. It isn't contaminated at all. I pump it out of the ground, then drop it right back into the water system where it flows back into the aquifer. And it is extremely economical compared to electric or propane heating, or traditional air conditioning. Open loop systems are the most efficient Geothermal systems. And yes, it is permitted. My electric bills are on par with what I used at my old house and I had to pay for water and sewage on top of that there. And I have about 2000 more square feet.

In your second diagram you show the outlet of the heater Tee'ing back into the house system I think? Can you just grab the out line from the heater and divert it directly into a sprinkler? How does the water throttle to 6gpm going through the heater? Is it throttled IN and free flows out or is the output throttled? How much pressure can the heater handle if you throttle the output? Where is the shutoff valve for the heater when it is not heating or cooling? Can you flow more than 6gpm through the heat exchanger if the sprinklers want it?

What I'm thinking is if the output of the heater is throttled then can you tap into the line just before the throttling valve and go directly to the sprinkler. A # 35 rainbird , https://www.rainbird.com/products/35adj-tnt-b-full-or-part-circle-brass-impact-sprinklers , will handle the flow. This also assumes that the heater will flow water when it is not heating or cooling.

lg
no neat sig line

 

[American Locomotive]

The geothermal system output is not likely designed to be severely restricted or tied back into the house system. It's also possible the water coming out of it would not be potable (depending on the metals the HX is made out of).

6GPM is quite a bit, and it's likely the pipe coming off your water tank and the main supply line that everything taps off of is too small to supply the necessary water flow.

If you really want to use the water from the geo system, it will need be dumped into a holding tank, and then you'd need a separate pump and pressure tank pulling water from that holding tank.

 

[Balvar24]

Water flows the path of least resistance. Add a balance valve on the geothermal system.

 

[Innovate1]

You need to look at the flow vs. pressure graph for the pump. 1 Hp at 140 feet isn't going to produce a huge flow.

What sort of a sprinkler are you running? Several in ground on a sprinkler system?

Does the well supply both the house and the geo system? Is the creek is the discharge?

Can you synchronize the sprinkler so it only runs when the geo system is off?