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General Liquid/Water Cooling Discussion For discussion about Full Cooling System kits, or general cooling topics. Keep specific cooling items like pumps, radiators, etc... in their specific forums.

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Unread 01-23-2004, 01:16 AM   #301
Cathar
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Quote:
Originally Posted by dima y
Cathar so that pump you got is better then the CM30P7-1?
Lower power draw (14W vs 22W when loaded)
50000hr MTBF (5.7yrs) as opposed 2500hr (3.5 months) <-- The big one
Just shy of being an Iwaki MD15-R (60Hz) equivalent PQ curve, better than a Danner Mag 3 PQ curve.
Real-world flow rates typically 90% that of what would be achieved with the Johnson at anything under 3GPM
Stick 2 in series and you'd have real-world flow-rates typically 20% higher than the Johnson at anything under 3GPM
Closed-impellor design (like the Swiftech MCP600)
10x10x10cm - including the barbs

$95 US as opposed to $150 US <-- The other big one

Quite frankly, it's about the single most ideal 12VDC pump for computer water cooling out there.
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Unread 01-23-2004, 02:36 AM   #302
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V12, as the Surplus Johnson's are "direct drive" there's no way to seal the rotating shaft, without some sort of bearing seal - and this is the component I (and I believe others) have reported to be leaking.
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Unread 01-23-2004, 03:00 AM   #303
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found the "brother" to the swiftech MC600 pump (whatever they call it)

Page 14 looks exactly like the swiftec pump housing to me
if you look at the bearing life 10,000 hours bearing life!!! thats what one of the catalogs i have says as well
http://www.arozone.com/downloads/0004-P.PDF

my guess is that swiftech custom ordered that pump in the 12volt version from the company. also explains the bearing problem the old version has been having.

Cathar thx for the STEAL deal on that new pump in town would you mind posting oppinions when you get it? i think i might just order one from them

Last edited by dima y; 01-23-2004 at 03:08 AM.
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Unread 01-23-2004, 04:17 AM   #304
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Quote:
Originally Posted by Cathar
2500-4000hr (3-5months) brush-life on the motor for the CM30P7-1, with no user-servicing. I'll pass thanks. Yes, the CM30 uses brushes.

This pump here is a MUCH, MUCH better choice. Have two on the way.
Are you sure Cathar?
AFAIK (from the CM series datasheet) the CM30P7-1 has a ball bearing permanent magnet motor.
Permanent magnet motors by conception are brushless...
This is one of the two big differences between the CO30 and the CM30 series (beneath the direct driven vs mag driven impeller).

Couldn't find any number for the MTBF although.

BTW, these Laing pumps look promising, what about availability and pricing?

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Unread 01-23-2004, 05:34 AM   #305
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So that 94$ one is the Bronze or Noryl Plastic one?
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Unread 01-23-2004, 05:35 AM   #306
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Quote:
Originally Posted by Turbokeu
Are you sure Cathar?
Pretty sure, unless the Johnson headquarters engineer was lying to me.

Quote:
Originally Posted by Turbokeu
AFAIK (from the CM series datasheet) the CM30P7-1 has a ball bearing permanent magnet motor.
Permanent magnet motors by conception are brushless...
Now one needs to ask oneself, what would a permanent magnet need with a ball bearing? How the CM30 is designed is that there is a brushed DC motor that spins an armature with permanent magnets on it (not electromagnets). This armature is sealed away from the impeller magnet (just like any other mag-drive pump). The spinning motion of the armature magnets turns the impeller around. I drilled the Johnson engineer long and hard on this to explain it to me in detail so I could understand just how the pump motor worked, and therefore why it was brushed.

Quote:
Originally Posted by Turbokeu
This is one of the two big differences between the CO30 and the CM30 series (beneath the direct driven vs mag driven impeller).

Couldn't find any number for the MTBF although.
Johnson try to avoid giving out that information. The engineer told me that I could expect up to 4000hrs of life span. I went to a marine shop today and poked through their manufacturers catalog and found the CM30P7-1 listed in there with an explicit 2500hr MTBF written in the information section. i.e. Johnson's official material states 2500hrs to be safe, but their engineer reckons 4000hrs is more typical. Either way, it's still just 3-5 months of continuous use.

The engineer informed me that Johnson are looking into making a brushless DC version of the CM30, but not to hold my breath on it appearing real soon.

Quote:
Originally Posted by Turbokeu
BTW, these Laing pumps look promising, what about availability and pricing?

CD
All answered in the thread I linked to. Available direct from the USA division of the parent company for $95 US each. The parent company is in Germany. The US website is http://www.lainginc.com/. Their German website is http://www.laing.de/.

The German engineering data for the D4 pumps can be found starting here:

http://www.laing.de/10Produkte/40Pum...en/00index.htm

They are made for solar hot water circulation.
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Unread 01-23-2004, 05:37 AM   #307
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Quote:
Originally Posted by satanicoo
So that 94$ one is the Bronze or Noryl Plastic one?
Noryl. Guaranteed for up to 60C water temps.

Here's the PQ curve. It's the D4 that I was looking at:

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Unread 01-23-2004, 05:47 AM   #308
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What I found interesting is the voltage range: 6-24V
You can actually run these pumps at up to 24V(!)
The PQ curves are for 12V operation.
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Unread 01-23-2004, 09:16 AM   #309
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GOD! 6-24V!

A must have!
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Unread 01-23-2004, 11:37 AM   #310
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Quote:
Originally Posted by V12|V12
BigBen2K,
Hey, I was just wondering about the leak issue with the cheaper Johnson pump (the $30 model) Is there any way to just completely seal the WHOLE impellor casing and what not? I mean it would be a bastard to open, but if it's sealed and running, then why open it? Thanks
Well, that's part of the problem.

If you look at the pics again, you'll notice that the impeller housing is vented, where the shaft sticks out of the motor.

Sealing those vents could cause the water leak to extend into the motor, and you definitely don't want that!
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Unread 01-23-2004, 02:27 PM   #311
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Interesting pump you found, Cathar. If/when my CM30-P7-1 gives up, I may look at that model for a replacement. Should fit pretty much the same.
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Unread 01-24-2004, 03:46 AM   #312
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Quote:
Originally Posted by nexxo
If/when my CM30-P7-1 gives up
I can tell you right now it's not a matter of "If". Figure on ~4000hrs of running time, or 6 months non-stop at best. Depends on how often you have it running for per day.
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Unread 01-26-2004, 11:44 AM   #313
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Does anyone have an opinion on packing the vents with petroleum jelly?
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Unread 01-26-2004, 12:34 PM   #314
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Quote:
Originally Posted by bigben2k
Does anyone have an opinion on packing the vents with petroleum jelly?

What vents are you talking about?

I use petrolium jelly to seal o-rings on my Mag 3, so it works wonders for sealing stuff non permanently. I think I was the one who came up with the idea of sealing the mag 3 with the stuff.

Do the "vents" leak or something?
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Unread 01-26-2004, 12:41 PM   #315
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I don't think that will affect the MTBF too much personally as the wearing out of brushes seems to be the cause for 4-6month life span. Don't know why you's spend a lot of energy making a pump leakproof that you know is going to die in your rig shortly...
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Unread 01-27-2004, 04:03 AM   #316
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Just a weird thought: In SCUBA we use a thin layer of silicon grease to aid in sealing "O" rings on gages and camera housings. The gages work at 3k psi.

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Unread 01-27-2004, 12:07 PM   #317
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Quote:
Originally Posted by pHaestus
I don't think that will affect the MTBF too much personally as the wearing out of brushes seems to be the cause for 4-6month life span. Don't know why you's spend a lot of energy making a pump leakproof that you know is going to die in your rig shortly...
I was going to bring that up, but since you beat me to it...

How does this pump fail? How does it "die", and what can anyone do to extend its life?

All I can think about, is how the manufacturer recomends the installation to be either horizontal, or "motor side up". I have to assume that it's meant to prevent water from flowing into the motor compartment.

Does a bearing seize, and the motor burn out as a result? Wouldn't the fuse (from the proposed support circuit) prevent it from burning out?

The only hint I've seen so far is that the brush holder (made of nylon) melts under extreme heat, so would some dielectric grease work, and if it does, how much longer can one expect this pump to live?
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Unread 01-27-2004, 02:23 PM   #318
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Brush holders made of nylon? Sounds like pretty weak design. All the parts I've ever seen made from nylon that involve force in one direction or movement, such as the brushes, have all worn out the nylon causing extreme slop. In the case of the brushes it probably causes the brushes move off axis enough to stop them working or even lock up the motor.
If the motor is meant to stay dry why would they not use bronze or something else?
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Unread 01-27-2004, 04:47 PM   #319
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Cathar, those pumps, have a max flow of 6 gpm @24 volts.
The pq curves go a litle above 6 gpm, they really look like they are made at 24volts.
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Unread 01-27-2004, 05:04 PM   #320
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Quote:
Originally Posted by satanicoo
Cathar, those pumps, have a max flow of 6 gpm @24 volts.
The pq curves go a litle above 6 gpm, they really look like they are made at 24volts.

The curves are at 12V. I spoke with Laing (the manufacturer) directly.

Quote:
those pumps, have a max flow of 6 gpm @24 volts.
Am curious where you got that information from though.

Last edited by Cathar; 01-27-2004 at 05:20 PM.
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Unread 01-27-2004, 05:19 PM   #321
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Quote:
Originally Posted by bigben2k

How does this pump fail? How does it "die", and what can anyone do to extend its life?
The brushes wear out. They are a material rubbing on the contacts. It is a constant rotational rubbing action that wears away at the brushes. Eventually there will be nothing left of the brushes and the motor will stop.
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Unread 01-27-2004, 05:59 PM   #322
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Quote:
Originally Posted by satanicoo
Cathar, those pumps, have a max flow of 6 gpm @24 volts.
The pq curves go a litle above 6 gpm, they really look like they are made at 24volts.
Oh, I just looked around. There is a D4K, which is a 24V model of the D4 (no K). Sure you weren't looking at that?

12V D4 here: http://www.laing.de/30Ausschreibungstexte/D412V.htm

24V D4K here: http://www.laing.de/30Ausschreibungstexte/D4K24V.htm
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Unread 01-27-2004, 07:50 PM   #323
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Anyone looked at 12v centrifugal pumps?
Like-
Jabsco Popular Centrifugal 12V DC Water Pump
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Unread 01-27-2004, 08:45 PM   #324
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I dont know if thats the 12v or 24 volts one.
I do believe thats the curve for the 12v pump at 12volts, equal to the 24 volts at 24 volts.

But i find it hard to believe thats the graph for the 12 volts, at 12 volts, and that it is able to run at 24 volts.
--->Are you sure that the 12volt one rated at 24 isnt the 24volt one?
--->And in this case is the 24 volt one able to do 48 volt?
Maybe im wrong, but in that case it wouldnt consume 14 watts.

Still a very nice pump indeed.


I checked the site
http://www.oberread.com/

And theres this:
Attached Images
File Type: jpg pump1.jpg (76.0 KB, 11 views)
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Unread 01-27-2004, 09:10 PM   #325
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Oberread is just a re-distributor. Hardly the most accurate source for their information, especially since they just converted the original manufacturer's metric data into US format.

When in doubt, talk to the manufacturer directly, which is exactly what I did.

Follow the links I provided above to the German parent company site who actually make the pumps. The 12V pump is indeed 1400LPH (~6.16GPM).

The oberread site has probably gotten the specs for the 12 and 24V models mixed up.

As for "hard to believe for 12V at 24V", it's not uncommon for DC pump manufacturers will use 24V rated wiring in the motors, and then rework the pump to run in 12V mode as well. This is less work for them to do this, and it often gives the 12V model a longer life-span. I was chatting to a Shurflo pump engineer about this while we were discussing MTBF's for various motors. He told me of the various continuously-rated motor models that they built, that while rated at 12V, were internally built to handle 24V power, and these were the more desirable motors to get a hold of.
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