Phasechange Resource, Prometeia Conversions and Builds Options

[Marci]

The following information has been collated from several online resources, with the main reference threads listed. A HUGE thanks must go out to Bowman, Gary Lloyd, Herefishy, Chilly1, CaptainCascade, DaBit, Gleep, Berkut and all the others who have contributed so much to the XS PhaseChange section in terms of useable information (think I managed to get y'all in there!).... without these guys I doubt I'd even be considering attempting any phasechange mods.

What follows is a summarised version of as much info as I could find on PhaseChange regassing concerning Prometeia units, and adds up to many hours hunting thru 40 page threads etc...


Prometeia Fresh Captube / Head Replacement - 404a
120" (3.048mtrs) 0.028 Cap Tube (then tweak down in length under load for optimum temps)

Prometeia Captube ADDITION - 404a (Using Stock Head or Baker18 Head)
58.5" (1.500mtrs) 0.028 Cap Tube (after load tweaking done properly, this length can end up reduced to as much as 36" depending on heatload applied to the evap head)

Prometeia Fresh Captube / Head Replacement - 134a/507a
61.5" (1.562mtrs) 0.028 Cap Tube

Prometeia Captube ADDITION - 507a (Using Stock Head or Baker18 head)
None Required.

Removing refrigerant with the Prometeia running cannot be accomplished by pushing the valvecore. Air will rush in then... introducing moisture into the system. All old/original gas must be vac'd out.

For optimum temps in both cases, extend total SUCTION line length by approx 5". Suction line is 3/8 Tube. Condenser lines etc are 1/4" Tube. Deepen trap loop on suction line. Replace existing drier with 20g (Captube Conn one side, 1/4" tube conn the other).

404a should be charged as a liquid direct to the high pressure side, or as a liquid thru the compressor's process tube. Fill til both high and low side are approx 50psi. Now we should be ready to fine tune the charge by slowly allowing gas to escape.

When modded to 404 or 507, condenser fans should be run at full speed at all times.

Load testing: XP1700+ (1.4Ghz stock, 133bus, 1.5vcore) at 2.8Ghz (200bus, 2vcore)

There are several methods for the initial charging of an EMPTY unit...

Herefishy says: "Charge until the suction return temperature nears the SST when nothing is connected to the evap. Exact amount, unknown... but in similar custom built units, around 3 - 4 oz of R404A does the trick."

Chilly1 says: "Generally, rough charge the Mach II to a suction pressure (with the highside gauge removed) to 5 inches of vacuum (0.17 bar) and allow it to run unloaded for 15minutes, then top it off to the same amount and test underload of 100W. The pressure should stay the same and the temperature will rise to -50C and stabilize. You can then add or remove gas in .01CC increments to taylor your charge for best temperature. If you are using R404 or don't have a highside tap you must let the unit stand for enough time to fully equalize. You cannot ever charge these with scales as the charge is smaller than that contained in your manifold set."

Gary Lloyd says: "Stick enough refrigerant in there to bring it up to positive pressure. Start the compressor. Add enough to make it run at the low side SST you expect to end up with. Wait until the evaporator reaches it's lowest temp under heavy load, then charge by best CPU Temp at heaviest load.

If you are charging without load, charge to near floodback... say 10 deg C superheat at compressor inlet. This is the maximum safe amount of refrigerant you can put in the system. You will have to remove some of it when you have heavy load on it to get optimum performance."

Under no-load conditions if the bottom of the compressor is cold or even cool there is too much refrigerant in the system. Remove gas a little at a time until the bottom of the compressor is warm. Put system under load. Allow evap to chill to it's lowest and level off. Remove tiny amounts of gas at a time. Temp should continue to fall. When you remove refrigerant and the evap temp starts to rise, you've removed a little too much.

It tends to put the compressor at less risk if you UNDERcharge and ADD gas then overcharge and remove gas... as if you overcharge too much you'll damage the compressor. Between each topup / removal, wait 10 to 15 minutes for the Unit and CPU Temps to settle at the new charge. When working from an initial undercharge, simply keep adding gas until the unit has "peaked" at it's lowest temp and then begins to rise again. As soon as it starts to rise, stop and remove a tiny amount of charge to get it back down to it's lowest again.

Once this is done... hook temp probes up for the following...

Monitoring Points:
1 - CPU Diode Temp & Undersocket Temp
2 - Evap head temp
3 - SST (Saturated Suction Temp) OR Low Side Pressure (and type of refrigerant)
4 - Condenser Air in Temp (Ambient Air Temp)
5 - Condenser Air out Temp
6 - SCT (Saturated Condenser Temp) OR High Side Pressure (and type of refrigerant)
7 - Liquid line temp near Condenser Outlet

There is NO POINT taking all these measurements on an uninsulated system, as insulation changes all the temps and you have to start again from scratch. If charging uninsulated, overgas so that you can start the system and remove gas rather than undercharging and adding gas. Insulate, then once completed fine tune the gas load removing a little at a time...

If you are performing mods on a Mach I system then you will need to put a 10k pot between connections 7 & 8 on the controller to allow you to adjust the temperature to keep it reading hotter than -50 deg C, otherwise alarm bells will begin to ring.

The full manual for the Mach I controller can be found here: http://www.over-clock.com/marci/2032.pdf

Main Reference Threads:
http://www.xtremesystems.org/forums/showth...ht=prommie+404a
http://www.xtremesystems.org/forums/showth...&threadid=24797
http://www.xtremesystems.org/forums/showth...&threadid=25956
http://phase-change.com/index.php?action=A...at=Guides&id=23
http://www.xtremesystems.org/forums/showth...rheat+measuring


Afterthoughts... AESTHETICS

Flexy Sleeving (Braid)
http://www.wirecare.com/wc_splashpage.asp?prodline=ho
http://www.techflex.com

Insulation
Armaflex (see http://www.armaflex.com)
Builders' Foam (local B&Q / DIY Shop)

Replacement Suction Hose
Parker 285-6 AirCon Hose (5/16" ID / 8mm ID) with 3/8" Flare fittings is my personal preference, 50cm length, with fittings precrimped on rather than manually self-fitted.

If using custom Baker18 Evap Heads, enclosures are now available to provide a mounting / insulation solution from xtwerks.com

Mechanical Info
ALL joints to be braised. Mechanical joints are unreliable by themselves. A small amount of sealant can be added to flares but generally is not necessary if the tube itself is correctly flared and the correct flare-nuts are used... Threads on flarenuts can be PTFE'd but again, not necessary.

[herefishy]

Hi Marci,

HEY! You really put a lot of work into this... and I admire that...

I personally know that you were *very* conscious regarding the cntent of this post.

You should make this one a *sticky*... then copy it onto another thread... and let us "hack it all to hell"...


Just kidding....

But I suggetst that you leav this thread *virgin*, make it a *sticky*, and only you edit it, when you have revised your operation.

So many **GOOD** threads like this, get trashed with the posters of agenda...

Cheers!

[Marci]

Good point that! Shall sticky n' close this, and open a thread up fer general discussion thereof....

And welcome to the boards d00d!! It's great to have you here...


Thread has now been created for the discussion of anything covered in this post here: http://www.over-clock.com/ivb/index.php?showtopic=3688