Conclusion: It doesn't work, I feel something is wrong but I just can't see it.

Aim: to get water flow from the tap.

Given: The 3000L tank already fills under the control of a float valve in the tank.

When the water is low, a command is sent to the M521 controller that sends 220v via relay LY2NJ to start the submersible pump.

When the tank is full a command via the float switch stops the submersible pump.

Required: When I turn on the tap water will flow and a timer attached to the tap will supply irrigation water for 20min in the morning and afternoon.

Circuit Working: Normally the tap is off so the relay is not energised, there is 220v on pins 3,4 and 220v sent to the EPC4 controller.

When I turn the tap on, the relay will operate via 220v on pins 7,8 and the lever springs will send 220v to turn on the submersible pump.

Sorry I don't know what happened with the editing. It all disappeared so I did it again now have 2 posts.

Adding to my great week.

22 minutes ago, carlyai said:

Sorry I don't know what happened with the editing. It all disappeared so I did it again now have 2 posts.

Adding to my great week.

I hid the other thread :)

Could you post some photos of your actual wiring to each of the units showing how they are connected please?

A second or third pair of eyes can often spot the silly errors that we all make.

The secret to sorting this kind of issue is to split into functions, for example: -

• What do you expect the EPC4 controller to do when you open the tap?

• Does it do it?

Once that is doing it's thing you can move on to the next process.

Thanks

OK it's a bit difficult to see but will try...just getting hot tongue and cold shoulder until I sort this. :)

2 minutes ago, carlyai said:

Thanks

OK it's a bit difficult to see but will try...just getting hot tongue and cold shoulder until I sort this. :)

I know this feeling only too well

Can you run manually until the automagic system is functional?

It still runs automatic or manual.

If you think the cct. is OK must be my wiring.

The diagram appears to show a pump is shared between EPC4 and M521 using relay changeover contacts. This suggests the tank fills via an open ended feed and the EPC4 water inlet is sharing the same line. How can pressure ever rise to stop the EPC4 if the line is always open to the tank?

The EPC4 detects both flow and pressure to achieve constant pressure operation. It requires no flow and a rise in pressure to cut off which is done by its control logic.

Correct me if wrong but I see the EPC4 calling a pump that will start filling a tank unless you have some device in line to stop this.

Hello.

The pipe to the tank has a ball valve and is normally closed unless the float switch calls the pump via the controller.

Without my electrics water flows from the tap (which is 3m lower and 15m closer to the sub. pump) if I manually start the pump from the controller.

I have an thought that I may not have wired the yellow tap controller as per diagram, maybe I switched N and L in either of the connections, but if cct. OK still should work...maybe...will check wiring again.

27 minutes ago, carlyai said:

The pipe to the tank has a ball valve and is normally closed unless the float switch calls the pump via the controller.

Without my electrics water flows from the tap (which is 3m lower and 15m closer to the sub. pump) if I manually start the pump from the controller.

In this situation the EPC4 would not shut off if the tanks ball valve was open. Normally you would not need a mechanical ball valve where a tank auto fills electrically.

The best way to handle this is to put a normally closed 220V solenoid valve on the tank feed.

EPC4 wiring is simple, mains in pump feed out. The EPC4 will fault if the conditions are not correct to energise its pump relay.

It is a mechanical ball valve.

This is my take or this is what I want: attached to the tap is a timer and valve. The timer opens the valve and as the tap is on and the pressure is lower at the tap water should flow when the submersible pump is turned on by the EPC4. After 20 mins the timer closes the valve, pressure equalises and the EPC4 turns off stopping the pump and water.

What do you think?

32 minutes ago, carlyai said:

It is a mechanical ball valve.

This is my take or this is what I want: attached to the tap is a timer and valve. The timer opens the valve and as the tap is on and the pressure is lower at the tap water should flow when the submersible pump is turned on by the EPC4. After 20 mins the timer closes the valve, pressure equalises and the EPC4 turns off stopping the pump and water.

What do you think?

If the tank ball valve is open there will be a pressure drop at the feed to EPC4 which will likely prevent it from turning off its output when outlet is closed.

The idea of having a irrigation timer valve on the EPC4 is good providing the EPC4 can get enough pressure from the pump to activate its pressure switch. Normally an EPC4 type controller turns on a pump that feeds it alone.

Here is a photo of an EPC4 type controller sitting on a shallow well pump. Its output connects to an irrigation valve and timer. When the irrigation valve closes the EPC4 sees not flow full pressure and cuts off after a small delay.

My aim was to use the EPC4 controller to turn on the pump but via a relay, similar to a 2 position switch.

Just now, carlyai said:

My aim was to use the EPC4 controller to turn on the pump but via a relay, similar to a 2 position switch.

Then you simply replace the pump with a 220V relay which is exactly the setup in my photo but in this case the relay is there to take the load off the EPC4 contacts.

4 minutes ago, Fruit Trader said:

Here is a photo of an EPC4 type controller sitting on a shallow well pump. Its output connects to an irrigation valve and timer. When the irrigation valve closes the pump sees not flow full pressure and cuts off after a small delay.

That's what I have but thru a relay.

The test is simple. When the tank ball valve is open is there enough pressure from the pump to satisfy the EPC4 pressure switch.

First test with tank ball valve closed.

220V on the EPC4 check

EPC4 output is connected to the pump directly - check

open the tap connected to outlet of EPC4 pumps runs - check

close the tap connected to EPC4 pump stops - check

Conclusion, EPC4 works ok now introduce the relay and tank ball valve.

On a happier note local OBT inspected and passed my solar installation yesterday and book full of ccts. etc submitted to PEA . Engineer expects approval next week.

All earthed and MEN link switching connected in the transfer switch. Faulty phase protector replaced.

As I didn't get an answer to my question if the circuit will work I asked some of my old students whose opinion was that the circuit would work, they also checked with Ai and cct. should work.

So I must have wired it wrongly.

I'm too scared to bugger around with this anymore as last iteration, when I turned the breaker on the pump measured 9A when it normally measures 3A then tripped.

Maybe it's something to do with switching the neutral and active (just switch the active) thru the relay. Maybe the 9A is just the start winding and not going to the run winding.

Plan B? Or in this project case up to Plan G :)

At the moment a float switch in the tank closes when low water and activates the pump thru the pump controller.

Maybe turning the tap on can activate a relay that closes a parallel contact with the float switch contact therefore turning the pump on via the controller.

Before wiring anything!

Prepare a logic diagram of inputs and outputs.

The inputs will be your level switch and flow sensor thingy and any other stuff you have that is supposed to influence it.

The outputs will be your pump(s).

Then for each set of input states define whether the outputs are active or not.

Look up Karnaugh Maps for an easy way to represent things. If you list your inputs and outputs I'll show you what your map should look like for you to fill in the states of the outputs.

Once you have a rigidly defined set of states it's pretty easy to implement using relays. Remember railway signaling systems were (and still are in certain countries such as Thailand) totally based around relay logic.

By the way, you should be able to make all this happen just by switching the live and commoning the neutrals.

9 minutes ago, Crossy said:

Look up Karnaugh Maps for an easy way to represent things. If you list your inputs and outputs I'll show you what your map should look like for you to fill in the states of the outputs.

I think it would be easier to use a Ladder diagram. But maybe that just what I am familiar with.

Sorry about the shadow

17 minutes ago, VocalNeal said:

I think it would be easier to use a Ladder diagram. But maybe that just what I am familiar with.

Sorry about the shadow

Sorry you add the R1 and T1 input terminal numbers next to the connection points as with the switched contact terminal numbers for R1 and T1. Etc..

I didn't know what they were.

Then you will see that you don't have to switch both

L &N for the submersible.

On 2/15/2026 at 9:51 AM, carlyai said:

As I didn't get an answer to my question if the circuit will work I asked some of my old students whose opinion was that the circuit would work, they also checked with Ai and cct. should work.

So I must have wired it wrongly.

Your diagram enhanced.

The diagram works if wired correctly. Its a simple relay circuit that shares a pump between M521 pump controller and EPC4 pump controller.

Relay off, M521 controller is connected to the pump and will power the pump via its own relay when required.

Relay on called by EPC4, the M521 controller is disconnected and pump gets direct feed.

This will work but as I already mentioned in this thread and back in Aug 2025 the EPC4 might not shut off if its supply is also filling the tank.

Thanks @Fruit Trader.

I decided to scrap that idea and go back to a previous plan, I can't remember why I didn't build that plan.

The tap controller 220v feed that goes to the pump (rerouted) will operate a relay and only use one NO contact set, that will be wired in ll with the float switch contact calling the pump controller therefore if either the relay contact or float switch contact make, the sub pump will turn on.

This also means that pump control is all via the controller and with have all the pump safeguards.

Will have another look in May when we return.

SWMBO is happy.

We have 3 bores and 2 were done 12 years ago when the available machinery only bored down 12 m, so we have trouble with these 2 shallow bores filling the back tank for the irrigation.

I've figured out a way to keep filling the back tank and just installing solenoids and timers to have 3 areas of irrigation.

5 minutes ago, carlyai said:

SWMBO is happy.

This is the single, most important statement in the entire thread!!!

Happy wife, happy life!!

And nookie of course

The original SWMBO!!

1 minute ago, Crossy said:

This is the single, most important statement in the entire thread!!!

Happy wife, happy life!!

And nookie of course

Sorry shop shut.

6 minutes ago, carlyai said:

Sorry shop shut.

Last word. If its a 3 wire sub pump don't forget the capacitor start when sharing the pump between controllers.