Finding pin holes in a closed loop system
 

Before thinking my pump is totally shot, how do I find pin holes in the pipe of my closed looped system? The pump will either hardly have any flow or it will work correctly and blow millions of micro bubbles. Thanks for any advise:biggrin:

I would think that if you had pin holes in your closed loop you would have water every where.

Tom R

some how it's air-locked?

I would think we would have water all over the place too. When hubby called the LFS, the fellow said we have air in the pump (don't know how it suddenly would get in there but any how...).

I shut the pump down, I also turned the water off to it, put my hand in front of the water inlet... did everything I could think of.

What is an air-lock and how would one suddenly materialize?

where are your closed loop pics?

are you going over the top with the feed to the pump?

This is the best picture that I have on hand at the moment. The pump is behind the skimmer. The feed to the pump is on the bottom of the sump if I am understanding your question correctly.

http://i388.photobucket.com/albums/o...otties/008.jpg

A true closed loop draws water from the main tank and recirculates it back to the tank, if this isn't what you have then it isn't a closed loop, if you have a link to the pic I might be able to see it in a larger format.

I cant get photos at the moment. The display is above the sump and fuge. The water goes from the sump, up into the pump, to the tank, back out through the overflows and into the sump again. Also the skimmer in the sump is not longer there. I guess the other skimmer blocks the view of the plumbing going upstairs to the display...

My husband built it and I just maintain it. He is not available this evening due to hockey so I'm on my own and don't know much about the guts of the system.

Is there any way to drain some of the tank water so it's just below the highest point of the CL system? Then fire it up again and see if that gets rid of the air in the line. Have makeup/top off water ready to fill....

so your just talking about your sump return pump a closed loop is a seperate pump like states above soley for flow to elimanate powerheads

Then it isn't a closed loop but a standard return.
It could be a number of things, but based on the fact that hubby is out playing hockey I would think that your sump may be running dry and air is being sucked in.

I already tried that... and boy it is good I have lots of water made already.:wink:

Check the sump.

I know it'll probably suck, but you might have to check the actual pump. Take the pump apart and clean it out. I don't imagine the sump could be runing dry...if you're anything like me you check it religiously

The sump is full. The water gets sucked into the return pump from the bottom of the sump not the top. The water would have to be drained right out for it to be sucking air. I feel that the pump is cavitating and on it's way, out but the LFS INSISTS there is a pin hole in my system. I don't know much abut how the system works but I cannot see how it is possible to have a pin hole to be honest. Sorry about my lack of knowledge on the set up. I watched it get built but do not know the technical names of all of it. I just take care fo the entire system except for broken things.:wink:

That is going to really SUCK (no pun intended:razz:) but that is my last option. I want to whine and give the excuse f... well I have filter socks how can there be anything in there, or the skimmer would have got it. It is the last option I have at the moment but at least I have ball valves to turn the water off as well as check valves.

I won't do it until morning now since I learned nt to touch anything before bed unless it was an emergency... Thanks for the tip though, it is a really god one.:wink:

Make sure the inlet to the pump is clear.

Cavitation and aeration are two different things. If the intake to your pump is blocked partially to fully cavitation will occur. If air is getting into your pump then airation is occurring. Im not sure if cavitation could cause microbubbles but checking the intake for restriction would be one to check on top of air leaks.

Thanks everybody I will check it out, just not tonight. If I touch anything this late Murphy's law will kick in... With well over 325g of water it could be ugly.

You guys are the best!!!:razz:

Just curious, what kind of pump is it?

A Blueline 100. Not happy with it. A killer on power bug time. Will be changing it.

It's pretty unlikely that you have something like a pinhole in the side of a pipe, you just don't have enough pressure to rupture PVC. If you have a hole it will be somewhere at the edge of a fitting where the glue has a space in it. This space could theoretically allow air to be sucked in by the movement of the water through the pipe like the venturi on your skimmer works.

In practice this is pretty unusual in a return line, the back pressure would be more likely to force water out of the hole than draw air in. Due to the rise in your system I imagine you have a check valve on there that will keep the pipe full with the pump shut down. Turn off the pump and look for leaks either in the plumbing or around the pump volute.

The answer to your question is cavitation

I had the same problem with a Iwaki return pump on my old 330G reeftank

Just put a ball valve or gate valve on the output side and throttle back the output a bit


bubbles gone :biggrin:

Not necessarily cavitation but something similar. Could you describe what the plumbing looks like from the sump to the pump? Likely this part of the plumbing has too much restriction which results in a low pressure situation. If the pressure is low enough dissolved oxygen will actually be liberated from the water, a very common problem that most never figure out and usually blame it on a pin hole which is actually pretty ridiculous when you think about it.

A quick fix is restricting the output flow of the pump as already mentioned, this will in turn increased the pump intake pressure. A better fix is to plumb the pump properly.

Restricting the output of the pump will reduce the cavitating, however if this system has been up and running for some time then this should not be the issue, and it sounds more like a restriction on the input side.

Well I did all that was mentioned and then hubby did the same. The pump will work fine, then suddenly have little to no flow, and then the bubbles with low to almost no flow. It has worked fine for abut five weeks since it was installed, and now for no reason at all it seems, it is doing this... I removed it and cleaned it but there was nothing in it at all.

It was not too bad at lights on but now it hardly flows at all and I have billions of little bubbles then none... then bubbles etc... etc...

We paid $600 for this pump and will be buying a different brand sooner then I would like. Prior to this one, we had an Iwaki and the same thing happened after about a month.

I'd be taking it back to whereever you bought it and raise a fuss. See if it's maybe common with that brand?? Sorry about the luck

I have a serious desire to come out there at some point and look at your sump. If this is the second pump that's done this, then something is up. Nobody is this unlucky (trust me, I know a thing or two about unlucky :p ) Something is not right about something, but without a detailed look I can't really speculate based on your descriptions (sorry, what I mean is, I can't visualize the setup)..

The first pump was not nearly strong enough to run the system. The LFS guy took a chance in selling the substandard pump for our needs, but he did the same for our skimmer as well. He ordered the new pump and we paid extra for it. When I brought the two week old skimmer back, I lost $100 on it and only got store credit.

24storm has been to my house a couple of times and he said everything was awesome. I do think it is bad luck to be honest.

I trust Keith's judgment but I still think there has got to be something else at work here. A pump can't fail because it's not strong enough ... if it's not strong enough to lift the water, you'll just have poor flow. However, if there is restriction on the intake side, then indeed, you are pushing the pump beyond it's limits and risking failure. In short, pumps push, they don't suck. Two pump failures in this short of timeframe may just be coincidence but it's now the point where I'm skeptical. If you have a third pump fail on you then I'll know it's not coincidence.

Who did the actual plumbing on your system, may I ask?

My hubby did it. The first pump just could not push the water at all, it goes up about 8 feet. When he gets home we will tear it down again. However, you are welcome to come over anytime you like... It is beautiful out here and if you like hiking, I can take you out...

Also what should I take pictures of to post exactly. I have my iphone in hand and can snap some shots.

if you can get a top down of the sump I'd like to take a look at it...

Give me 20minutes:wink:

QUOTE=Rbacchiega;392851]if you can get a top down of the sump I'd like to take a look at it...[/quote]

I have seen the setup a few times but i never paid attention to how it was all plumped. I aggree that something is not quite right with this. If you can get some pics of everything from the pump feed in the tank to the pump and then the lines coming into the tank that may help some.

Keith

Ahhh, ok, so the pump didn't fail, it just didn't fit the bill. Ok, I understand now.

Ok when you're back, I'd like to see how the piping for the pump intake looks. Ie., from the sump wall to the pump intake.

If you do indeed have a pinhole, my guess is it's along this section. If it is downstream of the pump (ie., after the output), then the line is going to be pressured up (particularly since you're lifting from a basement to the main floor) and you will have either leaking or saltcreep - ie., there will be a visual indication of a leak. So if you don't know about it, you probably don't have a leak in that particular section.

I hpe these are good enough but if there is anything I missed let me know. You cannt really see the pipes under the tank going to the overflows and I don't know if I can get in there to get a decent pictures.

http://i388.photobucket.com/albums/o...es/sump018.jpg

http://i388.photobucket.com/albums/o...es/sump017.jpg

http://i388.photobucket.com/albums/o...es/sump021.jpg

http://i388.photobucket.com/albums/o...es/sump023.jpg

Your pipe size is too small for what you're doing, by my rough calculations you've got over 6 feet of head pressure being created in that intake plumbing. If you jump up to 1.5" you're only adding about 1 foot, 2" you adding less than 1/2 a foot.

That's assuming your pump is wide open on the other end with of course it is not but to me the obvious solution is to swap out the plumbing for at least 1.5" or even 2". This will mean you'll have to re-drill that sump hole.

I sure hope you are wrong.... The LFS that sold us the pump also built the sump:twised: I think I have a headache now...

Im agree, first thing id do is see about upgrading you intake plumbing to something bigger. Even a slight restriction will cause cavitation.