Laing DDC Ultra 18W

Exsurgo

Exsurgo

Exsurgo

Associate
Joined
2 Oct 2009
Posts
829
Location
Belfast, UK
I purchased this pump from here about 2 years ago, and it has been flawless. Recently I left my pc unattended for 7 days straight while mining, and there were no problems.

Today I decided to do a little tweaking, overclocking, modifying settings etc.
So I run a bench and I got a nvidia bsod. At first I had no idea what was happening, so I ran more tests, got more crashes.

Confused I check gpuz : 93c. Sure enough the pump had seized.

For a while on boot the pump would manage a few spins and then seize again, so I repeated the process 10 or so times. Finally it seems to be spinning healthily again.

Has anyone had an issue like this with a pump? I have extra heat sinks added, so pump overheating should not be a problem. Obviously I am a little concerned it will happen again. I can see why people recommend dual pump loops.
 
They have a floating propeller to stop this sort of thing. Unless you have a build up on nasties growing in your loop I cant imagine it getting stuck.

Better safe than sorry and buy a new pump mate.
 
Strange thing is the loop is crystal clear, I have never even needed to clean it out. I did notice that the water level was quite low (~60%), and when I opened the reservoir there was a hiss and release of pressure, so obviously the air pressure was high inside the loop.

Going to replace parts of the loop anyway in a few months, and will keep a keen eye on the pump for now.
 
Weird I didnt think they did become pressurized.

If its clear it pretty much knocks out my suggestion of growing.

When was the last time the coolant was changed?

Long shot but if the rads were not properly flushed on build something may have dislodged and become stuck, cycling the pump may have freed it.
 
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Never changed the coolant, because I have never seen the slightest bit of gunk. I only top up the loop one every 6 months. I am also very surprised that the reservoir had become pressurized.

The previous owner of the rads flushed them religiously before sending them to me, and I also flushed them several times.
 
Hmm. In which case I advise an exorcist. Only other thing I can think off :D


lets hope it was a fluke. I cant find remotely similar on google.
 
You said in your OP that it reached 93c ... I'm surprised pressure didn't build up and cause a block to fail already.

Coolant in my loop reaches 43C max when 24/7 mining on an underclocked CPU and 7990.

I've had an i7 920 and they dump a lot of heat. My coolant temps were 30C on just an i7 920 that hadn't been overclocked, yours is on 4.2GHz which probably needed some volts. 480GTX was a nuclear reactor ... I'm not 100% sure but I'd bet a 470 isn't far off.

I'd be surprised if your coolant temps were below 40C ... and without anything to measure or record your temps, it's the only explanation to your pump failure.

Just consider yourself lucky and be thankful that it didn't cause more problems like cracking a block and spewing liquid all over your computer.
 
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I should have mentioned that the temp climbed up to 93c after the pump failed.

I have 12 fans on PWM attached to the radiators so I think that should be able to keep a reasonable cooling delta. The gpu temps sit around 35c with just the cpu priming, so I would assume the delta would be around 5c with water temps ~30c. (Only and estimation).

I have no doubt I got a little lucky on this one, I made sure to have a really good seal with both clamps and 7/16 tubing on 1/2 barbs, and have not had a leak so far.

The pump has been on 24/7 since the event and so far it has not missed a beat, so I guess I am at a bit of a loss as to what caused it to stop in the first place. One of my tubes has developed a very slight kink recently, so for now I have corrected it with cable ties. Will probably drain and retube the section shorty.
 
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