How I DIY my simple Auto Pump Cut-Off

[chrisyew]

Since I'm using a standard 2ft tank with no pre-drilled hole for overflow, I've a DIY overflow pipe. I believed most ppl like me are worried if one of these days, the overflow pipe decides to break siphon and the return pump will keeps pumping water from the sump to the main tank - imagine what will happen!

So an Auto Pump Cut-Off is much needed in this case to detect the situation so that the supply to the return pump is cut-off until the problem is resolved.

This is how my DIY Auto Pump Cut-Off(APC I) Model I looks like;

[chrisyew]

Here are some situations where the APC I are needed;

- When the overflow pipe breaks siphon, the main tank will be flooded with water and may even overflow from the main tank.

- When the overflow pipe breaks siphon, the last chamber of the sump tank may be drained dry by the return pump and may cause overheating of the pump.

Why is the APC I different from those Auto Top Off devices?

- When the return pump is cutoff due to any of the above situations, there will be a back siphon from the main tank to the sump tank thus causing the float switch to reactivate again in most Auto Top Off devices. So if one is using the Auto Top Off device to control this situation, your pipe to the main tank should not be inside the water of the main tank. But it will cause salt spray if the return pipe is not in the main tank too.

- Thus to resolve this back siphon problem, the APC I is used. Once the return pump is cutoff, the pump will not be reactivated even if there is a back siphon. In whatever situation, once the return pump is cutoff, it won't reactivate again until you have resolved the problem. To reactivate the return pump, both the float switch must be in Closed position and the Reset button pressed again.

When there is a Power Failure, will the return pump reactivate again once the power is resotred?

- Sad to say in this model, it will not be reactivated again but you have to manually press the Reset button to activate the pump. This is the pro and con of this model. But personally I rather not to have the house flooded or the return pump overheated than to cater for the power failure situation. Anyway, the chances of power failure is not that high.

Here is the APC I with the 2 Float Switches controllers;

[chrisyew]

Disclaimer;

If you are not completely comfortable working with electricity, then for your safety, and that of your family and tank, get a professional to wire it for you.

Construct this project at your own risk. I will not be responsible for any damage or injury caused by improper construction of these devices. The combination of electricity and water can be deadly, so please handle with care if you do not have the proper experience.

How it works;

- On the Main Switch.

- Ensure that both the Float Switches are in Closed position; i.e. the water level in the Sump is not below the bottom Float Switch and the water level in the Main tank is below the top Float Switch.

- Press the Reset button to activate the pump.

- As this Reset button is a momentary on/off switch, the switch is on when you press it but off when you release it.

- Once you press the Reset button, the relay will be activated. There will be a 12V AC supply to the bridge rectifier and to the relay coil as well. Thus the relay closes.

- This will supply the main voltage to the return pump, and the pump will start to work. The relay will not deactivate even if you release the Reset button.

- The only way to stop the return pump is when either of the Float Switches is Open, breaking the supply voltage to the relay coil. This will cause the relay to open thus the main supply to the return pump is stop.

- To reactivate the pump again, both the Float Switches must be in Closed position again, and the Reset button pressed.

Here is the circuit of the APC I;

[chrisyew]

Items needed for this DIY APC I;

- 230V to 12V Transformer

- 1 Bridge Rectifier ($1.50)

- 2 Float Switches ($18 to $22)

- 1 12VDC DPDT solid state relay ($3.50)

- 220V AC Bulb ($1.00)

- ON/OFF Switch (220V AC)

- Momentary ON/OFF Switch ($1.20)

- A small PCB to mount the relay but optional ($1.00)

- A plastic box to contain the items ($2.50)

- Plastic wire terminal connector small size ($1.00)

- 2 plug and socket (2 pin type) for float switch

- 1 2 pin socket for the return pump (depending on your return pump plug)

- Misc items like wire, sleeve, etc....

You may find all the above in Sim Lim Tower. For the Float Switch, there are 2 shops in the basement of Sim Lim Tower selling it ($20, $22) and Reef Depot is selling it for $18.

This is the Plastic Terminal Connector;

While here are some of the items shown except the capacitor and resistor which are taken out;

[chrisyew]

If you are not familar with relay, get this type which shown the pin configuration on the body (usually the number 12 indicates it's 12V);

[chrisyew]

Bridge rectiifier of this can be used. Try not to solder the bridge rectifier if your soldering skill is poor as it may 'spoil' the bridge rectifier due to overheating. Use the terminal connector.

[chrisyew]

Ensure that the box you purchased is big and enough height for the transformer and the rest of the items. Choose a bigger box if it's more comfortable to work with.

A smaller box will have messy wires inside hehe. Ensure the socket and switches have room when the top lid is closed and not obstructed by the items inside the box.

Well I'm rather embarrassed to show the inside of the box - what a mess hehe!

[chrisyew]

2 little plastic containers are needed to the float switch to act as snail guard or whatever intruders. The photo below show where to get such plastic container of the correct size hehe;

You need to make some holes on top and at the bottom of the container as shown.

[chrisyew]

Check the float switch with a multimeter to ensure it's working well. For one of the float switch, you will need to reverse the float by taking out the c-clip below the float switch.

Click link to see how float switch works;

Float Switch

Preparing the mount for the float switch.

The 2 mount for the 2 float swtiches.

[chrisyew]

Once tested that the float switches are working, now it's time to hook up to the sump and tank.

Here is the bottom float switch hook to the sump;

[chrisyew]

Now hook up the top float switch to the main tank;

Another view;

[chrisyew]

Now it's all hook up and ready to test for the worst situation.... and it PASS!

OK, it's all done now and ready for operation.

[chrisyew]

Note : I got the idea and inspiration from;

Credit :

DIY with Jon Garner - Reef Keeping

[chrisyew]

Items needed for this DIY APC I;

- 230V to 12V Transformer

- 1 Bridge Rectifier ($1.50)

- 2 Float Switches ($18 to $22)

- 1 12VDC DPDT solid state relay ($3.50)

- 220V AC Bulb ($1.00)

- ON/OFF Switch (220V AC)

- Momentary ON/OFF Switch ($1.20)

- A small PCB to mount the relay but optional ($1.00)

- A plastic box to contain the items ($2.50)

- Plastic wire terminal connector small size ($1.00)

- 2 plug and socket (2 pin type) for float switch

- 1 2 pin socket for the return pump (depending on your return pump plug)

- Misc items like wire, sleeve, etc....

You may find all the above in Sim Lim Tower. For the Float Switch, there are 2 shops in the basement of Sim Lim Tower selling it ($20, $22) and Reef Depot is selling it for $18.

This is the Plastic Terminal Connector;

While here are some of the items shown except the capacitor and resistor which are taken out;

I think I left out the Fuse holder and fuse (0.2A for my Ehiem 1250 pump).

[Guest]

Sorry i don't think that activating the relay during normal operation is a good idea. This will means that the relay will be ON most of the time. This will cause the life span of the relay to shorten. There by fail rate will increase ;(

[chrisyew]

Sorry i don't think that activating the relay during normal operation is a good idea. This will means that the relay will be ON most of the time. This will cause the life span of the relay to shorten. There by fail rate will increase ;(

Hi,

Thanks for pointing that out but I'm not too sure if this applies to solid state relay as well. This diy uses a solid state relay where there isn't any real mechanical contacts at all.

I've not try to run the pump in it's NC contact and I wonder will it work as there is a difference between a solid state relay (SSR) and a electro magnet relay (EMR). When there is time, maybe will try that out.

BTW, do you have any idea for a solid state relay, the NC contact can be used to run the pump - that means there is no power to the relay coil (Form C relay)?

[Guest]

well, not too sure if the picture of the relay you show is a "solid state relay". To me, inside that relay, there still magnetic coil that activate the switch, that's way you can hear the click sound when it is turn on.

In fact, i also did a device that function like what you have done. Only different is that the relay is Normally closed when pump is ON, and will remain forever Open when fault occur (till reset of course).

[chrisyew]

well, not too sure if the picture of the relay you show is a "solid state relay". To me, inside that relay, there still magnetic coil that activate the switch, that's way you can hear the click sound when it is turn on.

In fact, i also did a device that function like what you have done. Only different is that the relay is Normally closed when pump is ON, and will remain forever Open when fault occur (till reset of course).

So what type of relay you use? I'm not too sure if the relay I used is not solid state. May try to reverse the order if there is chance. Anyway, it's not that difficult to have it the other way.

[Guest]

i used something like yours. It's rated 10A. Bigger physical size

[chrisyew]

i used something like yours. It's rated 10A. Bigger physical size

OK, will pop by SL again to check it out. Will incorporate it in APC II. Think the APC II will have an external monitor with optional buzzer hehe. Thanks once again.