MD-30RZT Cavitating

Moony · 07-24-2004, 02:12 AM

I just put together an external box with a Iwaki Md-30RZT, Criticool Waterplant res, and 2-342. Unfortunately, I think the restriction of the inlet by the barbs on the Waterplant is causing the pump to cavitate because it is extremely loud (I can hear it throughout my house), bubbles are coming from the outlet, and when I throttle the outlet the pump gets quieter.

To remedy the situation, I ordered from mcmaster a 2'' OD 1.5'' ID clear acrylic tube and clear acrylic discs which I will fashion into a res that will fit directly over the pump inlet. The other end of the new res will be a 1/2'' od barb. Should this be sufficient in preventing further pump cavitation? Also, what should I use to seal the area around the new barb and the pump inlet in the new res, and what should I use to bond the acrylic.

Yogi · 07-24-2004, 03:13 AM

So I take it you're putting the inlet of the pump directly onto the res via some form of adapter? Not sure but isn't your inlet 3/4" npt (shot in the dark, specs would help)

You could grab a 7/16" drill bit and a 1/4"-18 npt tap along with any old 1/4" npt - 1/2" barb. That'd take care of your res inlet. For the res outlet / pump inlet you could find a 1/4" npt to 3/4" npt male/male (or male/female depending on what the pump inlet is) and use the same tools above. Or to really get flow going, which seems to be the entire point here.... Grab a tap for the same npt size as your pump inlet and buy the apropriate male/male (or again male/female depending) adapter. Then drill/tap holes accordingly, thread on your fittings with either silicone sealant on the threads or some good ol ptfe tape.

For bonding acrylic:

-Find a GLASS jar that you dont' mind trashing.
-Get a small scrap of acrylic and mash her into bits with a hammer. (don't need a ton)
-Put bits in jar and dump acetone in on top
-For say a 2" diameter jar with say 1/2" of bits o acrylic on the bottom fill up say... 1.75" of acetone. Stir occasionally ( hours apart ) and just let it work it's magic overnight.... LID ON THE JAR
-Keep waiting till it's 100% liquid that's not exactly water but not so much of a gel either, experiment with the consistancy on scrap arylic to find what you like to work with best... add acetone to water down, let set with no cover to thicken up.
-Apply carefully to one surface and push together.... let sit for a few hours and the bond is absolutly strong as hell.

Basicly all of that is to make a glue that more or less will melt the two pieces together into one, makes a crystal clear seam if done right.

Moony · 07-24-2004, 07:16 AM

Yeah unfortunately there are no threads on either the pump inlet or outlet. What size drill bits do I need to use to make the inlet/outlet of the res? Iwakiwalchem.com says that the MD-30RZ uses 5/8'' hose with 3/4'' NPTM. I'm not entirely sure what that means.

BillA · 07-24-2004, 11:56 AM

if you have threaded ends they are 3/4" NPT male
ck mcmaster copper fittings and adaptors

- upsize the 3/4" male end to a 1" spigot, put that into the branch of a 3x3x1 (reducing branch) tee set veritcally, and put a cap/plug on the bottom
- put a 2" length (net) 3" tube in the top of the tee on the inlet, and another 3x3x1 reducing tee wit the branch pointed in the direction that the inlet tubing will be coming from; put a threaded reducing bushing in the 1" branch
- sealed or vented ?
adapt to fit

note that the res for this pump should be 4" dia, 3" is minimal (velocity too high)
copper preferred for this app

Moony · 07-24-2004, 12:10 PM

I gooped the criticool waterplant res to the inlet of the pump...dremelled out the outlet of the res to fit. Will the new setup help with the cavitation on the pump? Epoxy is still drying. Will take pics later.

Moony · 07-25-2004, 12:41 PM

Okay goop is dry and the connection is good. Pump is still loud as hell though, and there's bubbles everywhere. I'm bleeding right now...will post later. Any help would be appreciated.

Titan151 · 07-27-2004, 02:09 AM

I had problems with cavitation before that were caused by using too much water wetter. Just a thought, although this may not be what is causing your problem. Of course I don't know what kind of cooling solution you are using. Hope you find the problem.

Moony · 07-27-2004, 06:53 AM

Just using distilled water while I test. No additives.

starbuck3733t · 07-27-2004, 10:37 AM

Quote:

Originally Posted by Yogi

For bonding acrylic:

-Find a GLASS jar that you dont' mind trashing.
-Get a small scrap of acrylic and mash her into bits with a hammer. (don't need a ton)
-Put bits in jar and dump acetone in on top
-For say a 2" diameter jar with say 1/2" of bits o acrylic on the bottom fill up say... 1.75" of acetone. Stir occasionally ( hours apart ) and just let it work it's magic overnight.... LID ON THE JAR
-Keep waiting till it's 100% liquid that's not exactly water but not so much of a gel either, experiment with the consistancy on scrap arylic to find what you like to work with best... add acetone to water down, let set with no cover to thicken up.
-Apply carefully to one surface and push together.... let sit for a few hours and the bond is absolutly strong as hell.

Basicly all of that is to make a glue that more or less will melt the two pieces together into one, makes a crystal clear seam if done right.

Acetone... like good nail polish remover? (acetone based obviously)

Yogi · 07-27-2004, 10:45 AM

Quote:

Originally Posted by starbuck3733t

Acetone... like good nail polish remover? (acetone based obviously)

LIke the $5 gallon that can be bought at home depot. Not sure about nail polish remover if it has any other chemicals in it.. if it does it would more than likely make an impure batch that'd cloud the joint.

Halo_Master · 07-27-2004, 01:27 PM

I have an iwaki md-20 an md-15 and i did have the same problems you are having. It made a lot of noise. But it is not cavitation or something like that.
These powerful iwaki pumps need a lot more resistance in a loop, when you load your lines with more waterblocks(adding resistance) and when you are using longer lines, the noise will dissapear. I have had the same problems, all is solved now.

Moony · 07-27-2004, 04:16 PM

Thanks for the help man...Cathar had the same exact suggestion. Right now the only restriction is the 2-342 rad (not restrictive at all) so hopefully with my cpu and gpu blocks I'll be able to quiet this thing down.

07-24-2004, 02:12 AM	#1
Moony Cooling Neophyte Join Date: Jun 2004 Location: New York Posts: 48	MD-30RZT Cavitating I just put together an external box with a Iwaki Md-30RZT, Criticool Waterplant res, and 2-342. Unfortunately, I think the restriction of the inlet by the barbs on the Waterplant is causing the pump to cavitate because it is extremely loud (I can hear it throughout my house), bubbles are coming from the outlet, and when I throttle the outlet the pump gets quieter. To remedy the situation, I ordered from mcmaster a 2'' OD 1.5'' ID clear acrylic tube and clear acrylic discs which I will fashion into a res that will fit directly over the pump inlet. The other end of the new res will be a 1/2'' od barb. Should this be sufficient in preventing further pump cavitation? Also, what should I use to seal the area around the new barb and the pump inlet in the new res, and what should I use to bond the acrylic.

07-24-2004, 07:16 AM	#3
Moony Cooling Neophyte Join Date: Jun 2004 Location: New York Posts: 48	Yeah unfortunately there are no threads on either the pump inlet or outlet. What size drill bits do I need to use to make the inlet/outlet of the res? Iwakiwalchem.com says that the MD-30RZ uses 5/8'' hose with 3/4'' NPTM. I'm not entirely sure what that means. Last edited by Moony; 07-24-2004 at 07:44 AM.

07-27-2004, 02:09 AM	#7
Titan151 Cooling Savant Join Date: Apr 2004 Location: Seattle Posts: 116	I had problems with cavitation before that were caused by using too much water wetter. Just a thought, although this may not be what is causing your problem. Of course I don't know what kind of cooling solution you are using. Hope you find the problem. __________________ Water Cooled AMD XP 4200 X2 Asus A8N-SLI Twin Raptors in Raid 0 Configuration 2 Gigs Corsair 3200 7800 GTX

07-27-2004, 01:27 PM	#11
Halo_Master Cooling Neophyte Join Date: Sep 2002 Location: Netherlands Posts: 44	I have an iwaki md-20 an md-15 and i did have the same problems you are having. It made a lot of noise. But it is not cavitation or something like that. These powerful iwaki pumps need a lot more resistance in a loop, when you load your lines with more waterblocks(adding resistance) and when you are using longer lines, the noise will dissapear. I have had the same problems, all is solved now. __________________ Intel PIV 3200@3840 DFI Lanparty pro875B 1024mb(2x512) ocz pc3700EB(2.5-2-2-5) Lian Li pc6070B Ati Radeon X800XT PE creative audigy 2 Silicon Graphics F180 (18,1 inch TFT) and nec-mitsubischi 930sb(black) jpiperformance V5 external watercooling(black) containing: -iwaki md20R -2x xlr120 rads -swiftech mcw6002

07-24-2004, 03:13 AM	#2
Yogi Cooling Neophyte Join Date: Dec 2003 Location: Texas Posts: 26	So I take it you're putting the inlet of the pump directly onto the res via some form of adapter? Not sure but isn't your inlet 3/4" npt (shot in the dark, specs would help) You could grab a 7/16" drill bit and a 1/4"-18 npt tap along with any old 1/4" npt - 1/2" barb. That'd take care of your res inlet. For the res outlet / pump inlet you could find a 1/4" npt to 3/4" npt male/male (or male/female depending on what the pump inlet is) and use the same tools above. Or to really get flow going, which seems to be the entire point here.... Grab a tap for the same npt size as your pump inlet and buy the apropriate male/male (or again male/female depending) adapter. Then drill/tap holes accordingly, thread on your fittings with either silicone sealant on the threads or some good ol ptfe tape. For bonding acrylic: -Find a GLASS jar that you dont' mind trashing. -Get a small scrap of acrylic and mash her into bits with a hammer. (don't need a ton) -Put bits in jar and dump acetone in on top -For say a 2" diameter jar with say 1/2" of bits o acrylic on the bottom fill up say... 1.75" of acetone. Stir occasionally ( hours apart ) and just let it work it's magic overnight.... LID ON THE JAR -Keep waiting till it's 100% liquid that's not exactly water but not so much of a gel either, experiment with the consistancy on scrap arylic to find what you like to work with best... add acetone to water down, let set with no cover to thicken up. -Apply carefully to one surface and push together.... let sit for a few hours and the bond is absolutly strong as hell. Basicly all of that is to make a glue that more or less will melt the two pieces together into one, makes a crystal clear seam if done right.

07-24-2004, 11:56 AM	#4
BillA CoolingWorks Tech Guy Formerly "Unregistered" Join Date: Dec 2000 Location: Posts: 2,371.493,106 Posts: 4,440	if you have threaded ends they are 3/4" NPT male ck mcmaster copper fittings and adaptors - upsize the 3/4" male end to a 1" spigot, put that into the branch of a 3x3x1 (reducing branch) tee set veritcally, and put a cap/plug on the bottom - put a 2" length (net) 3" tube in the top of the tee on the inlet, and another 3x3x1 reducing tee wit the branch pointed in the direction that the inlet tubing will be coming from; put a threaded reducing bushing in the 1" branch - sealed or vented ? adapt to fit note that the res for this pump should be 4" dia, 3" is minimal (velocity too high) copper preferred for this app

07-24-2004, 12:10 PM	#5
Moony Cooling Neophyte Join Date: Jun 2004 Location: New York Posts: 48	I gooped the criticool waterplant res to the inlet of the pump...dremelled out the outlet of the res to fit. Will the new setup help with the cavitation on the pump? Epoxy is still drying. Will take pics later.

07-25-2004, 12:41 PM	#6
Moony Cooling Neophyte Join Date: Jun 2004 Location: New York Posts: 48	Okay goop is dry and the connection is good. Pump is still loud as hell though, and there's bubbles everywhere. I'm bleeding right now...will post later. Any help would be appreciated.

07-27-2004, 06:53 AM	#8
Moony Cooling Neophyte Join Date: Jun 2004 Location: New York Posts: 48	Just using distilled water while I test. No additives.

07-27-2004, 04:16 PM	#12
Moony Cooling Neophyte Join Date: Jun 2004 Location: New York Posts: 48	Thanks for the help man...Cathar had the same exact suggestion. Right now the only restriction is the 2-342 rad (not restrictive at all) so hopefully with my cpu and gpu blocks I'll be able to quiet this thing down.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)