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Gheuett 08-17-2010 09:08 AM

Rain Collection System Using Collection Tanks in Multiple Locations
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My rain collection system started with one barrel and now I'm up to building two separate storage areas of 500 gallons and 1000 - each made up of multiple tanks strung together in two locations of our house. My plan is to bring the two collection areas together using PVC into the crawl space and connecting to a shallow well pump. That would then pump to spigots on each side of the house. A key piece of info is that the 1000 gallon collection area sits about 4 ft below the 500 gallon one. The 500 gallon area is complete. I have not connected into the crawlspace or done anything with the pump yet.

My question is - can I presume that if I connect the two storage areas with a T connector which then feeds the pump, water collected in the higher storage area will drain to the lower and will fill up only when the lower is filled? Anyone see any problems if this is the case? If so, I'm guessing the overflow would only need to be on the lowest of the upper area tanks.

I've attached a very basic sketch of how this will layout. (it is small though - sorry about that) Appreciate any input.


AllanJ 08-17-2010 10:23 AM

I am assuming closed tanks as opposed to open topped ones so the lower ones don't overflow while the upper level tanks can fill up and make use of their full capacity.

With all of the tanks interconnected, only one overflow pipe is needed, at the uppermost tank. But you need vents on all tanks so air pockets don't develop. I believe that they make but don't know where to buy open air vents that will close off after the air pocket has been replaced by water, and re-open when water is drawn from the tank to let makeup air back in.

A workable, simple, failsafe, but unattractive air pocket remover is a vertical pipe from the top of each tank up to a level just above the top of the uppermost tank.

An alternative to open air vents is a second set of interconnecting pipes reaching all of the tanks, attached to the tops of the tanks.

Gheuett 08-17-2010 08:32 PM

Thanks Allan!

Gheuett 09-12-2010 07:41 PM

5 Attachment(s)

Checking back in as I have made some additional progress but have questions related to the operation of my pump. In the pictures, the group of trash cans is part of the collection. They are connected in a manifold type of arrangement that feeds into the crawlspace where the pipe connects to the intake side of the pump. I have no check valve on the intake side because as I understand, if your pump is lower than the water source, you don't need one. There is a sediment filter in line also.

In the pics you can see the discharge which goes upward to a tee - one side goes to the outside spigot and the other is plugged for later connection to a manifold for an irrigation system.

My problem is the pump is continually cycling regardless of the spigot being open or not. It starts off pumping up to the max of around 50 PSI - shuts off then drops quickly and starts up again. It seems to pump water well. I've stopped all the leaks. There is a check valve on the discharge side. From the initial test of the tank, I've made sure that the appropriate pressure was pumped into the tank - right around 28 PSI.

Also, after you turn it off, there is a loud sound similar to a Harley motor that winds down slowly. The sound seems to be coming from the tank area. Appreciate any thoughts or ideas. Can send other pics if needed.

This is a Harbor Freight - Central Machinery Shallow well pump. It is about 1.75 years old but has only been used in the last month - out of the box.


Gheuett 09-14-2010 04:44 PM

Shallow Well Pump Operation
5 Attachment(s)
Hi All,

I am building a rainwater irrigation system that uses a Harbor Freight 1HP Shallow Well Pump to pump rainwater from above ground storage containers that feed into the crawlspace where the pump is located.

The problem I have is the pump cycles up to around 50 PSI and shuts down for about 2 seconds then powers back up. It does this whether or not water is flowing.

Right now, I have one outside spigot connected to the discharge side of the pump. There is a check valve on the discharge side but there isn't one on the intake side. There is a sediment filter on the intake. The pump sits lower than the source so as I understand, one is not needed. There are no leaks in the system.

I have been in touch with Harbor Freight Tech support and here are the recommendations I have tried:

  • One suggestion was to reduce the tank pressure. I originally pumped the tank to 28 PSI as recommended. One Tech suggested dropping it because my discharge PVC is only about 7' total right now. See PIC. Before I lowered the pressure, the tank made a sound that resembled a high pitched Harley when you turned off the pump. That has pretty much gone away as I dropped the pressure. Even with the reduced pressure (now down to about 10 PSI) the cycling has not changed.
  • The pressure tank appears to be holding its pressure so there don't appear to be any leaks there.
  • Adjust the pressure switch. I have tried adjusting both the large and small spring settings and I've managed to get the cycle to stretch just slightly longer but it still is a matter of 2-3 seconds.
I could understand the pump cycling when water is running through but when the spigot is closed, I would think it should pump up to 50 PSI and then stop until something changes such as opening a spigot.

I'm out of ideas. The pump does work well when hooked to a sprinkler etc. I'm just concerned that the frequent cycling can't be good in the long run. Appreciate any suggestions or ideas of where I might try. I can post additional pictures if needed.


jogr 09-14-2010 10:54 PM

So the tank stays at 50 psi but the pressure switch on the tank still triggers the pump?

Gheuett 09-15-2010 07:41 AM

It gets to 50 PSI then it shuts off. The gauge drops back to zero. The tech explained that the gauge doesn't register pressure when the unit switches off.


AllanJ 09-15-2010 08:01 AM

What do you use (system pressure, water level detected by a float, etc.) to turn the pump on and off?

I find it hard to believe that you sealed up the trash cans you are using as water tanks well enough so as to maintain any significant pressure.

Everything on the outlet side of the pump rests at the same pressure the pump shuts off at and what you measure at the pressure tank.

Be sure that the pressure tank itself is not full of water. Normally you do a rough calibration by turning the system off, emptying out the pressure tank, closing the pressure tank top valve, and turning the system back on. After that you optionally set the system pressure more precisely by putting air into the pressure tank top valve. If the pressure tank has no bladder (or a damaged bladder) it is necessary to recalibrate the system every few weeks, or more often if the pump starts cycling frequently, due to absorption of the air in the pressure tank.

All water pump systems including sprinkler systems need an air filled pressure tank.

Gheuett 09-15-2010 08:13 AM

My plan is only to switch it on when I need it. I have the outside switch that connects to the plug for the pump. Once I put it into operation, the pump switch will be left on and I'll just turn it on when needed. Rather than just use a straight pump, I wanted the on/off pressure switch capability so I could use a hose with a spray handle and not worry about having to have water flowing all the time.

You make a great point though. The water tanks are definitely not pressure tight and I wondered if that might have something to do with it. So could it mean that the pressure is simply pushing up through the intake side and up through the tanks?

Would a check valve on the intake side reduce that?


AllanJ 09-15-2010 08:18 AM

The pump may have a built in check valve at the inlet side. If not, the instructions should say when you need to install a check valve. Correction: cisterns, wells, and trash cans on the inlet side do not need to be sealed.

Sprinkler systems need considerable pressure (30 to 50 psi depending on number of sprinkler heads per zone) in order to operate properly.

Gheuett 09-15-2010 08:30 AM

There is a straight opening into the pump and no check valve. The instructions say if the pump is above your water source you need the check valve. This pump is below but I still wonder if it would help.

Thanks again Allan!

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