Q1: Unsure what the Aquabus connects too. Do I connect that to the Multiswitch? If so, then what is the advantage as I understand I don't need the USB connection from the Multiswitch to the Mother board?
If you connect it to the aquaero, you are able to control it via the aquaero. The big disadvantage is that you can only use it as a switch - on and off
I highly recommend that you connect the multiswitch to a USB port.
Q2: What is the Expansion Slot ment to be connected too?
It can be used for additional devices. Currently nothing is availble for this port.
Q3: Relay emergency shutdown, is this recommented and where do you get the cable for this?
Yes, highly recommend because it costs nearly nothing but makes your system more secure.
You could connect the power-button of your PC to the relay of the aquaero.
Q4: I assume that as the fans are infact small motors, I need to fit a self-induction recuperation diode and a 100 nF capacitor to the consumer to prevent intererences with the Mulitswitch, is this true?
Referring to the manual it is true. Can't say any more here...
Q5: Will the Multiswitch allow me to change the voltages of the fans between 12v, 7.5v and 5v with the software interface, or is it simply 12v on and off? This allows me to change the fan speeds and so the sound output of the fans.
Yes and no. The multiswitch uses PWM. Of course you can take control over the speed of the fans but you can't set a voltage, only one of 26(?) values (from low to max). PWM is only available when the multiswitch is connected to a USB port. If you connect it to the aquaero you can only use it as an off/on switch.
Q6: The Aquastream connection is not used due to the Aquero connected to the Aquastream, is this correct?
Yes, the port remains free because the pump is already connected to the aquaero.
Q7: Unsure what the Aquabus connects too. Do I connect that to the Aquaero? If so will I loose some useful functionality in controlling the Jumper 3 (PWM function)?
You could connect the multiswitch to the aquaero but as said before you would lose the PWM function in this case.
Q8: What device is the RPM-signal connection for?
The aquastream conntroller generates an artificial rpm-signal as long as everythings is working correct. If the controller detects a malfunction it will stop to generate this signal. You could connect it to a fan connector of your mainboard to monitor the pump and if the signal is lost the computer could be shut down (if configurable in the BIOS). Well, you don't need to do this because your aquastream is already connected to the aquaero and all malfunctions will be reported by the aquaero and of course it can shut down your PC if you use the relay.
Q9: Do I connect that straight to the Mother board, and how does the Aquaero know if the water leaks out?
No, you should not connect it to your mainboard. Connect it to the aquaero with an aquabus cable and the aquaero will be able to shutdown your PC (the relay again...) if a malfunction is detected.
Q10: Can you see anywhere where I have mis-understood the aquacomputer products and I am likely to damage anything?
Not really, but afaik 911 is a good number to call if something goes wrong ;D
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DO NOT connect the molex connector to the aquastream AND aquaero at the same time. This is only recommed if you encounter problems with the aquastream - most likely when you connect the tubemeter too.
btw: you know that you can connect more than one fan to a fan channel of the aquaero? Use a Y-adapter or solder them together. Remember that 10W is the maximum load capacity of a channel.