Pressure relief with flow restrictor valve

[dieselfuelonly]

So I've got my cistern set up for my low-yield well pretty much finished up, just working on the final parts of removing the old pressure switch/tank setup for the deep well pump.

My system looks something like this (excuse my MS Paint skills)

The well has a very low recovery rate and as the water level moves up and down in it stirs up a lot of sediment. To help reduce that sediment I have set up a backwash filter and a cartridge filter, as well as a a 0.75GPM Dole valve that should in theory allow the well to recover faster than I pump water out (the recovery rate is 0.83GPM).

I have the Dole valve located after the filters because I was worried about the amount of sticky sediment plugging the valve, although I realize the flexible nature of the rubber valve orifice helps prevent that.

I have set up a few valves so I can close off the flow from well pump and backwash the media filter from clean water stored in the tank.

The only issue I'm running into so far is the amount of pressure that the deep well pump is building up thanks to the restriction from the dole valve. Even with the filters clean, I watched a 100 PSI pressure gauge make a full 360 and keep climbing before I shut the pump off probably in the 125PSI range. The pressure relief valve did open up, so I'll have to see if I can adjust it high enough.

I feel like the 0.75GPM flow should be enough to keep the pump cool, especially since it won't be working as hard because of the restriction, I just worry about how high the pressure is going to get, especially running through the backwash filter and the cartridge filter. As I said above I worry about locating the Dole valve before the filters because of just how much sediment gets pulled up and leading to it getting plugged.

Just looking for any thoughts or ideas of this being problematic? I guess the other option is getting a rather large pressure tank that the well pump can fill up over the course of 30 seconds to a minute, and then spend, say, 10-15 minutes emptying into the cistern. But I'd like to eliminate the pressure switch and bladder tank altogether if possible and just let the well pump be controlled by a timer and/or float switches.

 

[Reach4]

You don't want a well pump shutoff valve. Turn off the power, and the pump will shut off.

You might want two float switches-- one controls the well pump, and the other inhibits the pressure pump if the cistern empties.

Putting a 1/2 hp 10 gallon pump horizontally in the cistern pump will be quieter and take less power than a jet pump. Pump should have a flow inducer.

 

[Sponsor]

 

[Valveman]

About 130 PSI is all a 10 GPM, 1/2HP pump can build. If you don't want that much pressure on the filter you will need to put the Dole valve before the filter. You also need the pressure relief after the dole valve as there isn't enough difference in pressure at zero or 0.75 GPM to adjust a pressure relief valve. I prefer 1 GPM to keep the pump cool, but at 0.75 GPM it will likely still be OK. You can use a Cycle Sensor to protect the pump from running dry. But I think you have a good plan.

 

[dieselfuelonly]

You don't want a well pump shutoff valve. Turn off the power, and the pump will shut off.

You might want two float switches-- one controls the well pump, and the other inhibits the pressure pump if the cistern empties.

Putting a 1/2 hp 10 gallon pump horizontally in the cistern pump will be quieter and take less power than a jet pump. Pump should have a flow inducer.

I should have clarified, the shut off valve for the well pump is simply to close that off when I am backwashing the sediment filter using the clean water in the storage tank, it's not intended to be closed any time except for that.

I agree with the two float switches - right now I just have switch wired in to shut off the power to the well pump manually. I will automate all that eventually. I have a jet pump right now and yeah it is noisy. If I replace it I might go that route of putting a submersible in the tank. If it is laying horizontally on the bottom of the tank how can I secure it? I don't want to rubbing against the bottom of the poly tank every time it turns on and off.

About 130 PSI is all a 10 GPM, 1/2HP pump can build. If you don't want that much pressure on the filter you will need to put the Dole valve before the filter. You also need the pressure relief after the dole valve as there isn't enough difference in pressure at zero or 0.75 GPM to adjust a pressure relief valve. I prefer 1 GPM to keep the pump cool, but at 0.75 GPM it will likely still be OK. You can use a Cycle Sensor to protect the pump from running dry. But I think you have a good plan.

Thanks for the info, I should have been a little more patient and seen how much further it would climb up before shutting it off. Right now the dole valve is located after the filters as I wanted to keep the chance of it getting clogged with debris as low as possible, even though they are supposed to be self cleaning. The idea of the relief valve before the rest of the filters/dole valve was to prevent the well pump from deadheading if the filters ever got completely plugged for whatever reason.

I'll have to see what pressure the system gets to with the filters clean and set the relief valve slightly above that I guess. Will take some experimenting I think.

 

[Bannerman]

Placing the backwashing filter and other filters before the dole valve, can subject them to higher pressured than they are designed to withstand. The pressure relief valve located directly after the dole valve but before the filtration equipment will continue to provide pressure relief protection even if the filtration equipment should become blocked.

The Cycle Sensor Valveman recommended, will also provide additional protection in case the well should be incapable to supply sufficient water to supply the pump.

 

[dieselfuelonly]

Yeah I looked up what the filters were rated for and 100PSI was the max for the cartridge filter housing. The well pump was definitely producing more than that. I guess my only option is to move the dole valve between the well pump and the filtration which I went ahead and did. I think I will have to relocate the dole valve outside!! It is EXTREMELY loud when water is flowing through it which then reverberates through all the plumbing for my storage tank. The 0.75GPM dole valve is really small, 3/8" fittings and the orifice is tiny which probably is what causes all the extra noise. I guess I'll just have to hope that no sediment is able to plug it up... wonder what the amp draw is on a dead-headed pump compared to running through this tiny valve? It would be nice to have some kind of protection if for some reason it did get clogged, be it detecting amp draw or through a pressure switch cutting power to the pump.

It is wild just how accurate the dole valve restriction is - I put a 1 quart container on the restricted side and it filled in exactly 20.00 seconds, so 3 quarts in 1 minute = exactly 0.75 GPM. Thought that was very neat.

Amp draw at the breaker is at 6.84 amps. I should have seen what my voltage was at but I'll have to check that tomorrow.

Will I be safe running this pump for hours on end with the restriction on it like this? If I figure on 300 gallons per day for usage at my house that ends up being a little over 6 and a half hours of runtime of the well pump needed to refill the storage tank. Assuming the well can keep up with the constant draw of 3/4 GPM (which it should from my testing), should I come up with a timer to run the pump for X amount of time and then stop for a while, or just let it rip for 6 and a half hours straight?

 

[Valveman]

If that is a 115V pump 6.84 amps is good as that is a 12 amps motor, so it is running cool at 6.84 amps. If it is a 240V pump the amps are already high as that is a 6.0 amp motor. A 12 amps motor running at 6.84 amps can run 24/7/365 and stay cool at 3/4 GPM, as long as the water is flowing past the motor before going into the pump. This requires the pump be set above the well screen or where the water enters the well. A flow inducer sleeve or shroud would be best if the casing is large enough, but not needed if the well feeds from the bottom.

There is not enough difference in pressure at 3/4 GPM and zero GPM to adjust a pressure relief valve. You might be able to protect the pump from running dry with amps, as they may vary slightly between 3/4 and zero flow. But we only make the Cycle sensor in 240V, so if it is 115V that won't work.

Dole valves are only supposed to have 120 PSI differential pressure max. If you have 130 PSI coming into the valve it will certainly be noisy.

 

[dieselfuelonly]

If that is a 115V pump 6.84 amps is good as that is a 12 amps motor, so it is running cool at 6.84 amps. If it is a 240V pump the amps are already high as that is a 6.0 amp motor. A 12 amps motor running at 6.84 amps can run 24/7/365 and stay cool at 3/4 GPM, as long as the water is flowing past the motor before going into the pump. This requires the pump be set above the well screen or where the water enters the well. A flow inducer sleeve or shroud would be best if the casing is large enough, but not needed if the well feeds from the bottom.

There is not enough difference in pressure at 3/4 GPM and zero GPM to adjust a pressure relief valve. You might be able to protect the pump from running dry with amps, as they may vary slightly between 3/4 and zero flow. But we only make the Cycle sensor in 240V, so if it is 115V that won't work.

Dole valves are only supposed to have 120 PSI differential pressure max. If you have 130 PSI coming into the valve it will certainly be noisy.

Makes sense about the noisy dole valve. Guess I'll relocate it out to the well house. It is a 240v pump. Wonder why the amps are so high then? No clue on how old it is. Never had any trouble with it.

 

[Reach4]

Why have the Dole valve -- to not stir things up, or to not run the well dry? If the reason is not to run the well dry, you could use a pump saver or similar, and let the water fill faster. If the water level drops, the device will shut off the pump for a programmable while.

 

[dieselfuelonly]

Why have the Dole valve -- to not stir things up, or to not run the well dry? If the reason is not to run the well dry, you could use a pump saver or similar, and let the water fill faster. If the water level drops, the device will shut off the pump for a programmable while.

Yeah the dole valve is to keep the water level from dropping in the well and stirring things up.

I hooked up the pump straight to the plumbing feeding the tank through the dole valve today and am going to let it run and fill up the tank. Hopefully all goes well. Pump is drawing 5.54 amps at 243 volts after several hours of running. The control box says 1/2 HP, but I guess it could possibly be more? Or some underlying issue with the pump that will eventually show itself. We'll see!