Question Unclear on how to properly fill water loop

MoreMoneyThanSense

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Aug 4, 2019
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Some questions about filling your custom loop, I've never played with the parts before in person so I am still operating on paper here

  1. Does the pump connect to the mobo to get its power?
  2. Are you supposed to "jump" your PSU somehow so you can turn the pump on and off without turning on the rest of the system?
  3. Whenever you fill up your reservoir (using a multiport top), are you supposed to close it before turning the pump on? If you leave it open will the liquid come up through the top of the reservoir? In other words what happens if you turn the pump on with an open port at the top of the reservoir?
  4. When you turn the pump on, are you supposed to then very quickly turn it back off when the reservoir is about a third of the way from the bottom, to give things a few seconds to turn off while ensuring you're not running the pump dry?
  5. Do you just keep repeating this process until the reservoir no longer drains all the way down?
  6. How do you ensure you're not introducing any contaminants, minerals, air bubbles into the loop?
  7. If you do have air bubbles in your system, how can you tell? Is it always obvious / visible? How do you correctly remove the bubbles?

Thanks
 
Does the pump connect to the mobo to get its power?
depends on your loop. mine does. but many use a Molex connector from the PSU.

Are you supposed to "jump" your PSU somehow so you can turn the pump on and off without turning on the rest of the system?
yes. there are jumpers for a few bucks available if you don't want to tinker around on your own with it

Whenever you fill up your reservoir (using a multiport top), are you supposed to close it before turning the pump on? If you leave it open will the liquid come up through the top of the reservoir? In other words what happens if you turn the pump on with an open port at the top of the reservoir?

depends on how fast the pump is and how full the reservoir is. usually before your reservoir isn't filled up to 90% water won't splash out. when filling you usually need a second port open so air can get out. when your loop is properly watered and ran for some minutes I close up. then run it for 2h or so closed. by then more air got dumped in the reservoir from the rads/blocks and the water line is significantly lower. I then power down, fill it up again, close the reservoir and let it work again. this way it doesn't splash out.
TL;DR: fill open with the pump running until the loop seems filled, then close. when everything has settled, add liquid with the pump powered down.

Do you just keep repeating this process until the reservoir no longer drains all the way down?
basically. you put in water to around 75% until it doesn't drain into your loop anymore but stays in the reservoir. then you fill up.

How do you ensure you're not introducing any contaminants, minerals, air bubbles into the loop?
don't know what you mean exactly. but for the most part: gravity. the point of the compensating reservoir is that you get rid of air bubbles easily since they rise inside the reservoir. takes some time though. having a second port on top open helps as well while filling since the air can exhaust easily and doesn't get trapped.

If you do have air bubbles in your system, how can you tell? Is it always obvious / visible? How do you correctly remove the bubbles?
it's not always visible or obvious, especially when you're using a transparent fluid/water. big air bubbles at the pump area you can hear. in the rads you can hear them too but not as easy. moving the case carefully around can resolve air bubbles from some nasty hard to get to areas (like the backside of your rad). changing pump speeds as well. but I wouldn't worry too much. 99% of air bubbles resolve themselves when your loop is filled within a few hours/days. I only had one nasty bubble just at the pump exit that prevented water to properly push through. powering down, then up again, shaking the pump gently worked easily. but as said, it's way less of a problem as you think.

custom loops sound so very complicating but it's really not that hard. I can only give you the following pointers:

  • get enough fittings. and get angled fittings. 45° & 90° fittings are so much better than straight ones. for some reason you never need straight ones imho.
  • get compression fittings. have some spares in case it turns out the 90° isn't as good in the position as you thought it would be. theory is nice and all but in the end when you're working you sometimes realize you made a planning error
  • make good measurements. my 3rd radiator fan didn't fit above the mainboard heatsink for 0,5mm. the pump didn't fit between drive cage and GPU for less than 0,54´mm. now it's sitting outside my case (which is kinda cool as well)
  • don't work with time pressure. assembling my first loop took me around 10h total + leak testing for 14h. but as said, I've ran into some space issues^^
  • don't worry too much about immediate leaks. I've splashed around 150mm of distilled water over my mainboard when leaktesting. leave it to dry for a decent amount of time (12-24h) and it's fine. as long as nothing's running it's not too much of an issue. no need to melt down.
  • get a water temp sensor. they're like 10$.
  • start with distilled water.
  • get some draining setup. either a drain valve or a quick-release connector. the latter is not a must-have but can be quite practical.
 

MoreMoneyThanSense

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Thanks for the detailed response.

When you are doing a pastel coolant does it make sense to do a fill / leak test with distilled first, empty/drain it, then fill with the pastel?

What's the correct way to drain? Does it matter whether you connect the drain valve to the Out or In tube on the reservoir? Does it matter if it's not at the absolute lowest point in the case? Do you just open a port on the top of the res and open the drain valve + connect some soft tubing to the valve, and that's it? Do people typically do any other kind of distilled flush to get the coolant out of all the parts/blocks/etc?
 
Thanks for the detailed response.

When you are doing a pastel coolant does it make sense to do a fill / leak test with distilled first, empty/drain it, then fill with the pastel?

What's the correct way to drain? Does it matter whether you connect the drain valve to the Out or In tube on the reservoir? Does it matter if it's not at the absolute lowest point in the case? Do you just open a port on the top of the res and open the drain valve + connect some soft tubing to the valve, and that's it? Do people typically do any other kind of distilled flush to get the coolant out of all the parts/blocks/etc?

so not exactly my area of expertise but:

  • yes, I'd leak test with distilled water. if something is leaking you're spilling distilled water over your board. no big deal. also it's a lot cheaper.
  • you generally want the drain valve to be at the lowest point to have gravity do it's thing. but I mean, just follow your logic. it's mostly in order to not spill the fluid over your things.
  • basically. just drain it into some bucket.
  • yes. it's adviced to flush all your stuff with distilled water. but it always depends on the fluid you're using. I've seen people using Mayhem pastel for 3 years and it looks as bought new. depending on the part you can also use pure ethanol to clean the blocks.