Yard Hydrant Timer

[CommanderDave]

I have two yard hydrants that are fed by a 25gpm-rated deep well located at a pond on my property. My normal operation of the one hydrant nearest the well head is for 24hrs a day for about 30 days in the spring to fill the pond from the winter draw down, and then I run it about 6 hours every night during the summer months. The other hydrant is at the dock house and is only used to hose down the dock, cleaning fish, or other intermittent use. My plan is to connect the well pump to a pressure switch (not a pressure tank) and then install a timer on the hydrant at the well. The hydrant timer needs to be capable of programming on the above schedule, and is also heavy duty enough to handle the high psi of the water flow from the estimated 20-21 gpm water flow. Can anyone recommend one? The threaded hose connection on the hydrant is 3/4", but I could install an adapter to make a bigger connection.
I understand that not having a pressure tank means that anytime a hydrant is opened the well pump will run continuously, which is what I want in this application, and the pressure switch will protect it when the hydrants are closed (or, please correct me if I'm wrong). Thanks.

 

[LLigetfa]

I understand that not having a pressure tank means that anytime a hydrant is opened the well pump will run continuously, which is what I want in this application, and the pressure switch will protect it when the hydrants are closed (or, please correct me if I'm wrong).

Without a pressure tank, the pressure could reach the cut-off setting on the switch and short cycle the pump to death unless there is enough flow to prevent the pump from out-pacing the flow. Have you actually measured the GPM the pump can produce?

 

[Sponsor]

 

[LLigetfa]

Also, without a tank and with the hydrant closed, the pressure can drop to the cut-in and short cycle (start) the pump.

 

[CommanderDave]

I did measure the flow and it was about 20gpm. So you are saying that I cannot set the pressure tank switch at a high enough cut-off psi to prevent short cycle? What would make the pressure drop to cut-in when the hydrants are closed if there is no bleed off anywhere? (Unless maybe the water drains back into the well?) When the well was installed we also ran a water line to the house in the trench for electric service, which was connected to the home's basement plumbing for possible future use or backup and currently kept closed off. (The house has a domestic well service). I believe my driller also installed a check valve in that line (would that prevent bleed off?). We also ran an additional wire to a contactor in the pond's well control box, and that is what would be connected to a pressure switch.
If I installed a pressure tank and switch, wouldn't it cycle the (20 gpm) pump many many short run times during the 30 days of continued flow in the spring, unless it was a very high capacity tank?

 

[LLigetfa]

So you are saying that I cannot set the pressure tank switch at a high enough cut-off psi to prevent short cycle?

Doing so could put it so far off the curve that it could possibly dead-head and not shut off if the water level in the well dropped.

When you measured 20 GPM of flow, what was the PSI? Do you have a published curve for the pump? How many GPM do you hope to achieve filling the pond?

Without the air reserve in a pressure tank, a tiny leak or even changes in temperature can cause enough of a pressure drop to start the pump.

Have you considered a small tank and a Cycle Stop Valve?

 

[WorthFlorida]

I did measure the flow and it was about 20gpm. So you are saying that I cannot set the pressure tank switch at a high enough cut-off psi to prevent short cycle? What would make the pressure drop to cut-in when the hydrants are closed if there is no bleed off anywhere? (Unless maybe the water drains back into the well?) When the well was installed we also ran a water line to the house in the trench for electric service, which was connected to the home's basement plumbing for possible future use or backup and currently kept closed off. (The house has a domestic well service). I believe my driller also installed a check valve in that line (would that prevent bleed off?). We also ran an additional wire to a contactor in the pond's well control box, and that is what would be connected to a pressure switch.
If I installed a pressure tank and switch, wouldn't it cycle the (20 gpm) pump many many short run times during the 30 days of continued flow in the spring, unless it was a very high capacity tank?

Water alone cannot hold pressure since it cannot be compressed. Air is needed to be compressed to provide the force to hold pressure. For what you want to do is what LLigetfa suggest, a Cycle Stop Valve but it still requires a small pressure tank.

Constant Pressure Pump Control Valves

Constant pressure pump control kits, constant pressure pump control valves, and pump monitors

cyclestopvalves.com

 

[CommanderDave]

I have attached a drawing of the pond well and hydrants configuration. Again my desire is to have both hydrants pressurized and the well to only provide flow when opened. I would install a programmable timer on the hydrant feeding the pond, which I would remove in the winter and also turn off power supply to the well.