The ship, it is sinking! (DDC leak)

berntserker · 11-17-2009, 03:46 AM

My DDC 3.25 seems to be leaking in a very strange way.

First noticed it when I had the pump mounted vertically with the nozzle up.
Water would very slowly start to build up underneath the pump and run down the side.

Drained, removed the pump, dried it out and mounted it outside the case in a loop with only a reservoir in it, and no leaks.
The pump got much hotter to the touch than previously, but no leaks whatsoever.

Changed my loop so the pump is mounted horizontally, left it running for 12 hours, just standing freely in the bottom of the case.
A small drop has formed underneath the pump, and water seems to be leaking, infrequently and in very small amounts from the center of the bottom where the pin is.

Have tried tightening and loosening screws, but the result seems to be the same.
A small, but infrequent buildup of water from the bottom (see attached illustration.)

Is there anything I can do to mend this myself, like buying a thicker o-ring or is this pump a dud?

Eddy_EK · 11-17-2009, 03:57 AM

I'd say replace the o-ring or RMA it.

Tex707 · 11-17-2009, 04:14 AM

Quote:

Originally Posted by berntserker

My DDC 3.25 seems to be leaking in a very strange way.

First noticed it when I had the pump mounted vertically with the nozzle up.
Water would very slowly start to build up underneath the pump and run down the side.

Drained, removed the pump, dried it out and mounted it outside the case in a loop with only a reservoir in it, and no leaks.
The pump got much hotter to the touch than previously, but no leaks whatsoever.

Changed my loop so the pump is mounted horizontally, left it running for 12 hours, just standing freely in the bottom of the case.
A small drop has formed underneath the pump, and water seems to be leaking, infrequently and in very small amounts from the center of the bottom where the pin is.

Have tried tightening and loosening screws, but the result seems to be the same.
A small, but infrequent buildup of water from the bottom (see attached illustration.)

Is there anything I can do to mend this myself, like buying a thicker o-ring or is this pump a dud?

All you have to do is accept it is your fault and you're gonna feel just fine

Seriously, don't even think about putting in an O-ring of a larger body diameter.

Sadasius · 11-17-2009, 04:59 AM

+1 with what Eddy suggested. Ignore Tex707. In fact he is going on my ignore list now.

voigts · 11-17-2009, 09:17 AM

I would also recommend an RMA. The fact that the pump bottom is getting unusually hot is probably an indication that it needs to go bye-bye.

PiLsY · 11-17-2009, 05:33 PM

RMA definitely, forget changing the O-Ring. Its new, it shouldn't leak

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Tex707 - trolling is taken very seriously here so i'd be careful with your posts if I were you.

ohms · 11-17-2009, 07:30 PM

I'd say change the O-Ring if you have one laying around before you spend the money and the downtime RMAing it if you do not have a backup pump.

As for mounting it vertically, I know quite a few people have mounted the MCP/DDCs in various different positions without having any problems so I do think its an unrelated issue.

@Tex707 i'd take PiLsY's advice.

quattro_ · 11-17-2009, 07:52 PM

+1 just RMA it, but before you do can you do me a big favor and shoot a picture of the pump's PCB ?

Petra · 11-17-2009, 09:41 PM

Quote:

Originally Posted by voigts

I would also recommend an RMA. The fact that the pump bottom is getting unusually hot is probably an indication that it needs to go bye-bye.

Indeed... they tend to get quite hot if the motor has come in contact with water and shorted something, amongst other reasons.

A leak around that center pin, though, kinda suggests a bad seal around the ceramic bearing. If the water were coming from the large, circular hole in the pump's lower housing, then I'd think o-ring. The center bearing support column is hollow, though, and drilled in the volume compensating version of the DDC to allow fluid to pass through the bearing support column and out the bottom of the pump into the volume compensating diaphragm. If there happened to be a bad seal between the support column and the ceramic ball, then it could cause fluid to leak out around the pin in the bottom of the pump.

Tex707 · 11-18-2009, 03:47 AM

Quote:

Originally Posted by Petra

Indeed... they tend to get quite hot if the motor has come in contact with water and shorted something, amongst other reasons.

A leak around that center pin, though, kinda suggests a bad seal around the ceramic bearing. If the water were coming from the large, circular hole in the pump's lower housing, then I'd think o-ring. The center bearing support column is hollow, though, and drilled in the volume compensating version of the DDC to allow fluid to pass through the bearing support column and out the bottom of the pump into the volume compensating diaphragm. If there happened to be a bad seal between the support column and the ceramic ball, then it could cause fluid to leak out around the pin in the bottom of the pump.

This sounds very reasonable. I am not fully aware of the details of the design, but if there's a hollow bearing support that could definitely be the point of concern.

@ all who found my previous post wrong in any way: my sincere apologies, I'm not trolling, just made a joke (even put a smiley there). Still think the same about the O-ring, though...

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