Problem with Rotary SS - need fast help :/

[symphy]

Hello everybody,

One of the units we prepared for CeBIT showed a strange behavior yesterday...
It's the VGA loop (9000 BTU Rotary, 2 Evaps) of Phase9, the great unit Piotres build for me.

I did not power on the VGA loop for the last... 4 months as i was not VGA benchning all the time... But now i installed two G80 GTX and switched it on. Sound was abnormal. Pressure raised very quickly to 20 bars and climbed up to 25 bars within 10 minutes. The first evap was at the normal temp of ~ -45°C very quickly (as usual), but the second one needed veeery long (the second one always needs longer, but not so long). After... ~ 15 to 20 minutes both evaps were at -45 °C and the pressure began to fall to ~ 19 bar. Low pressure side was at ~ 1 bar at the beginning, and at ~ 0 bar when the other side reached 19 bars.

I booted the system and put load on both VGAs, pressure didn't raise again and both evaps have been at around ~ 45 even under load.

A friend of mine who builds units told me that properly all the oil flew down to the compressor and the compressor would have to spread it again over the entire loop. Just a suggestion, but even he said he isn't sure at all.

As i'm no phase change guy i just want to know now if everything is okay and if there's a logical reason for this strange behavior....

BTW: Pressure was nearly changeless while the unit was not in use, i checked it every week to recognize a possible leak... Pressure with two X1950 was around 14 bars iirc.

So, sorry Peter, i wrote you a PM but you went offline too soon i suppose :X.

I just want to know if everything is okay with the unit, because we leave for CeBIT this night... And the temperature at CeBIT will be much higher than the temps at my room...

TIA!

[piotres]

Hi

If static pressure in GPU loop is changeless and compressor is working unit rather can't be damaged ;) .

That 20 bars sounds a bit high (but it's still quite "safety" pressure for short time using), maybe try to run it a longer time and check pressures on high side again. 13-18 bars is normal pressure :) .

The most important think in using that unit : both CPEVs knobs must be screw equal, becasue GPU loop won't be working well when that not be exual . But I guess You haven't touched CPEVs since play on X1950s, have You ?

"A friend of mine who builds units told me that properly all the oil flew down to the compressor and the compressor would have to spread it again over the entire loop. Just a suggestion, but even he said he isn't sure at all."

That's very possible, if even sound was abnormal in some first seconds ...

Regards
Peter

[symphy]

Hi

If static pressure in GPU loop is changeless and compressor is working unit rather can't be damaged ;) .

Thanks. You prevented my suicide right now. :D



That 20 bars sounds a bit high (but it's still quite "safety" pressure for short time using), maybe try to run it a longer time and check pressures on high side again. 13-18 bars is normal pressure :) .

The most important think in using that unit : both CPEVs knobs must be screw equal, becasue GPU loop won't be working well when that not be exual . But I guess You haven't touched CPEVs since play on X1950s, have You ?

Regards
Peter


Nope, CPEVs are at exactly at the position you set in august last year :). I only touched the CPU loop CPEV... (-94,4 °C btw, and not 100% closed...).

So i will wait until my mate arrives to tighten the screws at the GTX a little bit more (my fingers are bloody, no joke, and he's better at using tools as i am) and insualte them properly (until now only mask and thin armaflex layer at the back, evaps naked copper).

I'll report in what the unit does under longer load or after a longer run.


Hi

"A friend of mine who builds units told me that properly all the oil flew down to the compressor and the compressor would have to spread it again over the entire loop. Just a suggestion, but even he said he isn't sure at all."

That's very possible, if even sound was abnormal in some first seconds ...

Regards
Peter

That sound was SO strange, and really, really loud. At first a single BANG!, and after that you heard that the compressor was very unhappy with its situation, working very very hard, but it gave its best i think. :D

Thanks Peter ;)

[piotres]

Thanks. You prevented my suicide right now. :D



Nope, CPEVs are at exactly at the position you set in august last year :). I only touched the CPU loop CPEV... (-94,4 °C btw, and not 100% closed...).

So i will wait until my mate arrives to tighten the screws at the GTX a little bit more (my fingers are bloody, no joke, and he's better at using tools as i am) and insualte them properly (until now only mask and thin armaflex layer at the back, evaps naked copper).

I'll report in what the unit does under longer load or after a longer run.

Thanks Peter ;)

OMG You have beat mine last record with single-stage with that -94.4*C, You bastard :D try to reach -100, that should be quite easy ;)

[symphy]

I hit those really deep temps not by purpose... The -94,4 was at a Lan party (again, a LAN Party), at the entrence hall. We just put the unit down from the car, powered it on, went out to smoke a cigarette, came back, switched on thermometer... and... bang! :D

But i dont think someone has taken a picture. If it's getting cold outside (probably this spring, we sometimes have even snow at may...) i will move the unit outside and close CPEV. :D

[piotres]

I hit those really deep temps not by purpose... The -94,4 was at a Lan party (again, a LAN Party), at the entrence hall. We just put the unit down from the car, powered it on, went out to smoke a cigarette, came back, switched on thermometer... and... bang! :D whoa nice show on lan party :D

But i dont think someone has taken a picture. If it's getting cold outside (probably this spring, we sometimes have even snow at may...) i will move the unit outside and close CPEV. :D do it, do it :D