Re: My venture into my new 760 ltr aquariam.
Auto Water change
The Mains powered timer turns on and energises the coil of the relay.( the green one ). This makes the contacts and connects the power to the blue relay by shorting out the float switch and the relays open contacts . The timer would then turn off. It only needs to be set for a second or two. Its just there to start everything off. The green relay is only there as the timer has a 240v AC output and I want to turn on a 12v item. I might be able to source a timer that has a switched output rather than a powered one , if so I can do away with the green relay and use the timer switch contacts to latch the blue relay.
As the float switch is in a normally closed position (this is mounted in the main tank at the low level cut off) this will allow this relay to stay activaited. This relay will now stay activated until that float switch drops and breaks the circuit.
Using a second set of contacts in this relay this will now run the 240v pump that will drain the tank.
At the same time a float switch located in the top of the main tank will make contact as the water drops. The float switch in there will drop and make the circuit to its relay.( the uncoloured one) This will turn off the sump return pump until the water level rises again which it will do when the main tank is filled with water.
Once the main tank water level drops to the level set by the float switch the switch will break the circuit , the relay will open and the pump will stop.
The water level in the tank will rise until it reaches its level and is stopped by a float valve on the incoming water supply. This supply is mixed hot and cold from my combi boiler. Saves storing heated water. Just heat what you need when you need it.
Once the water is at the full level it raise's the float switch which will break the power to the relay and the sump pump will start running again.
Water change complete.
I may use a 3rd set of contacts to stop the water supply via a solenoid valve rather than a float valve in the main tank as this only wants to work when I am doing a water change.
I want my water top up due to evaporation ect to happen in the sump tank . This will take place using a float valve.
Anyway these were my first thoughts on automating the water change. Its done from items I understand the workings off.
I could be done with electronics but that’s past me.
The reason for the 12v side is so all the control side is 12v . This means its only 12v at the float switches.
Simon