Dug Well To Greenhouse Through Unheated Building?

[LCF]

Hi everyone. I am new here but was hoping to get some ideas about the best way of going about setting up my water line for my new 70 foot greenhouse.

I have a few wells on my farm, and just installed a new 80x30 high tunnel greenhouse. The well that is closest to the greenhouse is tied to a building that I use for storage. The building has a furnace, but I don't heat it in the winter.

I put a pump in the building last fall to get the water going, and I drained it in the winter so it wouldn't freeze, but today when I fired it up water leaked out the bottom so apparently the pump froze.

The greenhouse is 20 feet from the building. I was planning to run a poly line from the outside of the building, trenched down 4 feet underground to the greenhouse where it would connect to a frost proof hydrant.

My problem remains though, how do I set it up so that the pump won't freeze in the winter. I could get rid of the pump in the building and put it in the greenhouse which will rarely dip below freezing, but how would it remain primed unless the water line goes directly to the well and not up into the building before connecting over to the greenhouse?

Any ideas would be appreciated. I am including a diagram of how I was going to set it up though I don't think it will work without heating the building.

 

[Reach4]

A submersible pump does not need primed, and it is much more efficient.

A submersible could be horizontal near the bottom of the dug well inside a flow inducer (piece of 4 inch PVC pipe).

Regarding freezing, poly may survive freezing, but it is better to have a way to drain the water before a hard freeze. Compressed air can be helpful for that.

 

[Sponsor]

 

[LCF]

I never even considered the idea of putting a submersible down inside a dug well.. I am open to that.

Will I need a pressure tank and pressure switch inside the greenhouse to control the pump?

 

[Reach4]

If this were only for irrigation, and the irrigation spigots/heads are always open, and if the pump and load are reasonably sized together, you would not need a pressure tank or pressure switch. You would use an on-off switch.

If you have a pressure switch, you need a pressure tank at the switch.

If you search this forum for submersible horizontal flow inducer, you will find some discussions. You could search for submersible horizontal and get more threads.

 

[LCF]

We are trying to copy what the neighbors did with their same greenhouse. They have low pressure drip irrigation, but that is connected to the frost free hydrant valve and it only waters when the turn the hydrant on. I guess if I went with drip irrigation I would need a pressure tank to keep the well pump from burning out, correct?

I did find a sub pump online that says no pressure tank is needed, though I am not sure this will work with irrigation. Never installed something like this before and I will also read up on submersible horizontal flow inducer.

 

[Reach4]

I would not feel good about a pump with that description.

Ideally for irrigation, the pressure will stabilize between the cut-in and cut-out pressure. As the pressure rises, more water comes out of the exits. As more water is delivered, the pressure drops. Ideally, there is a spot where it balances.

It is definitely easier to design with a pressure tank and pressure switch. But if you can balance, it will be more power-efficient and longer lasting.

 

[LCF]

I could do a pressure tank and switch and its not the end of the world if I have to, but it would require me to insulate it so if it does dip very low in the winter, it won't freeze.

As for the irrigation, the neighbors did mention something they use for flow reduction, or something? So that the high water pressure is reduced to work with the irrigation lines.

 

[Valveman]

The only time you need a pressure tank/pressure switch is if you want to open a faucet and have the pump come on automatically. If all you have are drip zones, you will need a 10-15 pressure regulator for the drip line, and you can run the system manually or with a sprinkler clock and you would not need a pressure tank. As long as you use more than 1 GPM on all the drip zones the pump will be fine.

You can even rig up a drain back system so every time the pump shuts off the lines drain back to the well to prevent freezing.

 

[LCF]

So without a pressure tank, how would the pump know when I need water? If I lift up the handle on the hydrant, what turns on the sub pump? Do I need to wire the pump to a switch so I have to also turn on a switch to give it power?

If I have to turn on a switch, will the pump run constantly while the drip lines are giving water, or do the pumps turn off when they reach a max pressure?

 

[Reach4]

So without a pressure tank, how would the pump know when I need water? If I lift up the handle on the hydrant, what turns on the sub pump? Do I need to wire the pump to a switch so I have to also turn on a switch to give it power?

If you have a hydrant, you would keep it on, and you might want to put a lock on the switch to make sure the pump does not get powered if a valve is closed. A pressure relief valve would be a backup in case you messed that up.

If I have to turn on a switch, will the pump run constantly while the drip lines are giving water

Yes.

If all you have are drip zones, you will need a 10-15 pressure regulator for the drip line, and you can run the system manually or with a sprinkler clock and you would not need a pressure tank.

You could set the timer to off hours (2am to 4 am for example) if you can get realtime power rates where you are.

 

[Valveman]

You want the pump to run continuously when the drip system is on. Pumps are made to run continuously. Cycling on and off continually for the many hours a drip system runs will destroy the pump.

Submersible pump in the well, bleeder orifice 5' from the surface, pressure relief valve above ground, 15 PSI regulator before any drip line, then just turn the pump on with a breaker or timer when you want water. Just don't use any valves or at least make sure there is always a valve open when the pump is running. When the pump is turned off, all the water will drain back through the bleeder.

 

[VAWellDriller]

So here is my trick for this exact situation....we have a lot of 30" concrete cased bored wells around here. I get a 1 x 24" stainless nipple, and screw it to the discharge of a 1" slide pitless . I then install this through the casing (the entire pitless is in the well) with about 6" inside the well, and 18" outside the well, connect house or service line to it, and concrete it in place with a couple bags of fast setting quickcrete. Inside, I have a stainless manifold with a 4.5 gallon tank and a cycle stop; hydraulic cement to grout on the inside. It's all below frost line so it won't freeze. The slide pitless makes it simple to service, you pull the tank and all out at one time.

 

[Valveman]

So here is my trick for this exact situation....we have a lot of 30" concrete cased bored wells around here. I get a 1 x 24" stainless nipple, and screw it to the discharge of a 1" slide pitless . I then install this through the casing (the entire pitless is in the well) with about 6" inside the well, and 18" outside the well, connect house or service line to it, and concrete it in place with a couple bags of fast setting quickcrete. Inside, I have a stainless manifold with a 4.5 gallon tank and a cycle stop; hydraulic cement to grout on the inside. It's all below frost line so it won't freeze. The slide pitless makes it simple to service, you pull the tank and all out at one time.

Now that is pretty cool!