Help needed: trapped air, defective pump, normal behaviour? (1st time wc)

[Farinorco]

Hi, I have finally put together my first watercooling loop, and I'm currently testing it for leaks and so. I'm having a "little" problem, I hope you watercooling gurus by here can help to enlighten me about it.

My pump is a Phobya DC12-260 (rebranded Jingway DP-600P, 600 l/h, 2.6m) that I have connected to a Cooltek fan controller, and I have a Tecnofront Visual Trap as a reservoir, which shows flowrate by a little ball that is pushed up by the incoming water (the higher the ball the higher the flowrate). Because of this flow meter, I have detected an "anomaly" with the pump.

When I powered on the loop for first time, the ball was barely pushed up (it was a little, but very little) . After some minutes, it suddenly went up a couple inches (if I am understanding it well, showing a flowrate somewhere between 300 and 400 l/h, or 1.3-1.75 gpm) . I thought it was air trapped on the pump that was keeping it from performing at its full potential. Then, I left the loop working while I went to sleep.

Today, I have been making some more tests, and I have noticed that every time that I switch off the power, or turn down the pump voltage in the fan controller to the minimum (5v) or very close to it, and then I turn it on/up again, the ball does not go up accordingly until after some time. That time is variable, for example I've made a quick test while I'm writting this, and it has recovered the higher position in seconds. But it can take several minutes to do it. If I turn down and up the voltage but not close to the minimum, I can see the ball going down and up accordingly at the moment.

I can think of several possibilities why this could happen:

* There's some air in the pump (maybe a big air bubble that depending on its possition may affect the pump performance or not).

* The pump is somewhat defective and it doesn't work properly (I hope it's not this one...).

* It's because of the reservoir flow meter (I mean, the pump is working properly but it takes a little while the ball is pushed up, then it keeps in its position). I really doubt this one because of the inconsistency of the different tests.

* It's normal behaviour of the pump to take some time to reach it's full potential. I really doubt this one because... well, I wouldn't say this should be normal behaviour at all...

I don't want to mount the loop on the components until I'm sure that everything is correctly bleeded, and every part is working as it should. So, what do you think about it? What should I do now?

Thanks for your help, and sorry about the length of the post. I want to give the more details I can in order to diagnose the problem.

[daedao]

I know this is old, but I'm contemplating the ideea of buying this exact pump Phobya DC12-260, so what was the problem you had with this pump Farinorco?

Was it the pump? It's a good pump from your experience? Did you change it for another one?

I have a i7 920 and a Radeon 5850 and plan to watercool them, maybe with this pump. I might change the AMD 5850 for a AMD 6950/6970.