Strange high temps with DD?

[Strida]

I just switched processor/motherboard from a 144/DFI to a 148/Epox and strangely enough, the 148 is idling ~ fairly high (20 to 40C) where the 144 used to idle fairly low (-30 to -20C). The only other thing that I've changed is that I've moved and when I moved I've positioned my system differently.

Before the move I had everything level in a chest. The motherboard sat flat at the bottom of the chest and so did the compressor/phase stuffs.

After the move I now have the phase system sitting on a small table (about 2 foot high) and my motherboard above it on my desk (~ 3-4 foot without measuring). The suction line is long enough to point upwards from my phase system and arc up above where my motherboard is now and bend back down to my processor.

The temp probe on my evaporator is reading somewhere < 50C but my processor is way, way above that in temps. The evap is a cap-in-cap design with a hole drilled at the top corner of each cap.

Another strange thing -- in trying to figure out what's going on I started adding more propane to see if I needed a bit more kick in the system in case a schraeder valve leaked some refrigerant, what came out was refrigerant and some oil with it (splattering all over, and also misting into the air and then dripping out of the hose once I had closed the manifold's valve). Could the new positioning be causing oil build-up or something?

I also thought that maybe oil was collecting in the bottoms of the caps in my cap in cap evaporator, and the refrigerant was escaping through the holes in the top of each cap before getting to the copper baseplate. My evap temp probe is located on the top/side of the outermost cap so that might explain the low probe temps and high processor temps.

I have also remounted the evaporator well over 10 times trying to figure out if it was just a mounting problem. Even popped the top off of it! The temp has varied a bit between mountings but still nothing near what it should be.

Anyone have any advice or ideas? I'm just an ignorant experimenter when it comes to this phase stuff so I can't say that I know exactly what I'm doing all the time, heh.

Thanks for your help and for the read,
Derek

 

[Pf.Farnsworth]

I dough it has anything to do with oil.

You could have broken a braze somewhere are loosing pressure and refrigerant and pulling in air. Check for leaks.

What is the heat houtput in watts before and after. If your system was tunned for a specific heatload its entirely possible that a few extra watts would send it overboars. You can tune for two things, low temeratures or capacity. If your system was tuned for the lowest possible temeratures at your given load then a small increase would send your temperatures skyrocketing. For instance if your metering device with your old load flows just enough, and witht he new load you are starving the evap your temperatures would rise.

Its the old capacity vs temeratures compromise. Put the old heat load back on and see if the temperatures will go down. If yes you will just have to retune your system, will rise your temperatures a little but atleast it would be able to hold your load at a decent temperature. If they wont drop with the old heatload then you have a problems elsewhere.

 

[greenmaji]

Uhh.. you built that phase rig so you cant be too ignorant at this point..

But what Pf.Farnsworth is telling you is right on the money.. you either have a leak or your system is undercharged for the heat load now (it needs a wee bit more refigerant)

 

[Strida]

Heat output before was with my 144 clocked anywhere between stock and 3ghz. The temp on it was always around what I posted originally (-30 to -20ish) and the evaporator was always less than -45 but generally below -50.

Heat output now is with a stock Opteron 148. The heat load should be similiar or identical since they're both Opterons and an extra 2 multipliers shouldn't change how hot the processor is.

I have actually tried overcharging the system up to the point where I get ice going to/around the suction line on the compressor. I have also let out charge to see if that had an effect -- either way the processor temps are still way too high (20 to 40).

I'm going to try 2 things, first is to change out the processor to my old one, second is to raise my phase system to the same level as my evaporator. I'll check in and post my results after each.

 

[Pf.Farnsworth]

Uhh.. you built that phase rig so you cant be too ignorant at this point..

But what Pf.Farnsworth is telling you is right on the money.. you either have a leak or your system is undercharged for the heat load now (it needs a wee bit more refigerant)

mmm, thats not exactly what I said. I said he either has a leak, which implies low charge, air and moisture in the system, and loss of pressure. Or the metering device is not tunned correctly for the load, ie too restrictive starving the evap of liquid.

Also the metering device esspecialy if it is a cap line, could have become more restrictive due to getting clogged by a peace of oxidation crud that could have fallen of the inside walls of his system when he moved it and got logged in the cap tube.

I recomend to test with old proc and see if that helps, if not

get some soap water and test every braze for leaks, if no leaks

Replace the cap line with a new one, or better yet with a CPEv, its a valve with adjustible restriction, so you can tune on the fly. I think the name is CPEv but I could be wrong, there are a few names for them.

 

[Strida]

Just got off work and I didn't have a chance to do any tinkering today. I'll try tomorrow and see.

I don't know, I've had problems with moisture in the past (which were resolved after a very thorough triple evac) and it doesn't seem like that's what's holding me back. My temperatures aren't fluctuating like they would/should if I had moisture build up on my evaporator. Remember, the evaporator's temp is < -50C but my processor is too high. If ice were building up @ the bottom of the evap, it would still be colder than 20-40C I would think. Also, if it were a moisture problem it would probably be far more likely for the moisture to freeze in the cap tube and not the evap. Also, ice/cold is going back through the suction line and keeping it cold -- so not enough refrigerant seems unlikely to me.

I guess I'll try and see what happens tomorrow! Thanks for the help everyone.

Derek

 

[Strida]

Replace the cap line with a new one, or better yet with a CPEv, its a valve with adjustible restriction, so you can tune on the fly. I think the name is CPEv but I could be wrong, there are a few names for them.

Alright, been looking into these Constant Pressure Expansion Valves and I want one. Can't find anyplace that has got them for sale though. XtremeSystems says to go to eBay, but I've had no luck there. Only TXV valves.

 

[greenmaji]

Send this guy a message on ebay, he'll list one for you.
Pf.Farnsworth.. any ideas on the details here he's running R290.
And yes I was very short on the sumation but I thought he could read the remainder of the infromation given (I didnt want to be THAT repetitive)
You had some advice when building, did you purge well for the brazing process? The chance of oxidation might be high (I doubt anyone gave you the correct method for using only 290, most have a serious hate for it, and you were not getting NO2), Pf.Farnsworth is on to something with the clogged cap tube idea.

 

[Strida]

I didn't end up purging and just chanced it; however, when I brazed my cap tube on I put it directly after my filter so that I would hopefully eliminate most of the oxidation issues. I guess my idea of putting cap tube right after the filter might not have worked out as well as I hoped.

 

[greenmaji]

The chances of no oxidation with no purging are about 0%

 

[Pf.Farnsworth]

The chances of no oxidation with no purging are about 0%

not if you are in space

 

[Strida]

Rofl. I realized there would be oxidation, but I thought since I put the cap tube RIGHT directly after my filter/drier I would be okay since a majority of the oxidation, if it were to make an issue, would be stopped at the filter.

 

[greenmaji]

But dont you have to braze the cap line to the filterdryer?
And that wasn't the intended purpose of the thing in the first place..

check out the "how to make a perfect flare" thread lol (I would just PM Xenon on how to use 290 to purge correctly to be honest, he probibly knows) Ive seen it done, but I would be giveing an educated guess tbh

 

[Strida]

I've had bad luck with flares. I might try them again if I end up tearing apart and re-assembling my system though.

I will get ahold of Xenon on purging with propane. I also got a cylinder of good higher purity propane instead of the crappy torch/camping propane I've been using. This should (might) help my temps as well.

I should have waited a week before saying I am going to work on this thing. Right now I'm getting ready for finals/etc. so I don't have enough time to test out what you guys are suggesting (though the advice will come in handy once I get time).

Thanks,
Derek

 

[Pf.Farnsworth]

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