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I have a single storey house with all downpipes connected to a large 11,000 liter underground concrete rainwater tank approx 1.8m deep. The tank contains a submersible pump servicing 5 outlets - 3 inside the house (toilets/laundry tap) and 2 garden taps. The tank's outlet is connected to a rain switch and a pressure switch housed in a box fixed to the rear brick wall of the house. The inlet valve is connected to incoming pipes coming from the house's downpipes.

The tank is currently full and I just discovered that the pump tries to start when a garden tap is turned on but then straight away cuts out with the LED panel light showing "pump failure". So I need to get the pump out to find out why it is not working and if not, then replace it. The pump is a NON LABELLED brand supplied and installed by a builder now gone broke and the house/tank and pump is ONLY 2.5 years old.

I cannot see the pump when I look into the top of the tank from the manhole.

  1. How do I get it out?
  2. Can I replace it with any other similar type submersible clean water pump and connect to the SAME rain switch? (This switch will switch between Town or Tank water if water is below a level in the tank or the pump fails)
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2 Answers 2

If the pump is a 3-wire submersible with a control box, you can do some basic troubleshooting with an ohm meter without pulling it. If you have a control box like this:

Franklin electric control box

Then you can pull the top off. Inside there are terminals that have black, yellow and red wires that go to the pump. Inside the cover of the control box, it will tell you the resistance ratings (in ohms) between each of the colors, which you can check with any standard multimeter. If those readings are off, then the pump needs to be replaced. If they are OK, the next thing to check is the current draw. You need a multimeter with a current clamp on it, like this:

enter image description here

and you need to be able to clamp around one of the wires while the control box cover is on. The red wire is the starter wire, so it should have a high current then go down. The others should draw whatever the control box says is the normal current draw for the motor. You can measure either the wires going to the pump, or coming from the panel.

If the current draw is very high before it shuts off, the pump is probably jammed. You'll need to pull it and possibly take it apart to fix it.

If there is no or very low draw (and the ohm readings are ok), the control box is probably bad, and you can just replace it without pulling the pump.


I used to work for a company that did that kind of work. Anytime we installed a pump in a cistern like that, we would use a pitless adapter to attach it to the incoming pipe. They're normally used in drilled wells to be able to pull the pump.

pitless adapter

If you are lucky, then yours has one too, and all you need to do is screw a threaded pipe into the top of the adapter to be the pull bar (typically 1 1/4"), and then pull it straight up and out. Because you are not using clean potable water, and especially if it hasn't been pulled in a long time, it may require some "gentle" persuasion to get it out. Wiggling and/or using a T-shaped bar (which you can hammer from the bottom) usually does the trick.

Before you put it back you should check the o-ring, and lubricate or replace if necessary. It's not really as important in a cistern as it is in a well, since if it leaks the water just goes back into the cistern, and the pump doesn't have that far to push water anyways, but it's just good practice.


I have run across cisterns where this wasn't the case though. If the pipes come in through the top, you may just be able to pull them and pull the pump out. If not, you may be able to cut the pipe, and then pull the pump from there.

If those methods fail, or if the pipe enters the cistern at the bottom, then the only way to get at it would be as @longneck says and drain the whole thing, then crawl in and get the pump out.

If you do have to drain it, it's a good oppertunity to clean it as well. There is likely a lot of sediment built up on the bottom that you can get out with a shopvac. Spraying it down with a pressure washer probably won't hurt either.

I would highly recommend that before you put the pump back in, you install a pitless adapter.

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Gregmac This is just great. I will study your answer indepth and check out the pump. There is a control box but I can't tell if it is similar to what you show. I will come back to you on what I find. meanwhile I really appreciate the time you have taken to produce such a detailed answer. Thank You! Mark –  Mark Fonseca May 5 '11 at 0:36
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You're going to have to drain the tank.

Go to a home improvement center with a rental division and rent a pump to empty your tank. You can then climb down and access the pump.

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What 11,000 litres - where will I empty the water? This is the size of a swimming pool. –  Mark Fonseca May 4 '11 at 21:27
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@Mark: have you considered adding a swimming pool in your yard? :-) –  BMitch May 4 '11 at 23:15
    
@MarkFonseca I don't know about your area but since this is rainwater perhaps you can dump into the stormdrain. –  Matthew Aug 22 '12 at 18:28
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