How???

[kindai]

How do people do setups with the rad/rads higher than the res without the water emptying down into the res when the system is turned off?

When I watercooled years ago, the rule was the res always had to be the highest point in the system to stop air locks, but this seems ignored nowdays?

 

[Uncle Petey]

I found that the back pressure issue (if that's what it's called) only occurred when there was a large air bubble further forward in the loop.

With that sorted, my res level doesn't change when the system is off.

 

[doggo]

If I'm understanding you correctly I'd say it's not a problem.

I've got a 120 and a 240 rad both are higher than my pump and res, once the res is full and loop is closed and you've purged they system of air there's no movement other than that produced by your pump.

 

[Jokester]

The water doesn't flow out of your radiator down into a lower res as the water needs to be displaced by air to allow it to move. Even with the res open it won't happen. If you're radiator has a bleed screw though and you undo it whilst the res is open, then water will flow out of the rad, into your res and depending on the volume of water, out of the top of the res as well.