Fluval 206 constant air lock

00101 · 09/29/2013, 08:12 AM

I'm working on fixing up my fluval 206. As the title says, it constantly is in air lock. When it is in air lock it makes a pretty awful and loud clicking noise. When it is like this, it doesn't move any water either. The longest its managed to run before going into air lock is about 10 minutes. Once it goes in it can't get itself out, hell I can't even get it out sometimes. I've tried just letting it run, and it just sat there and clicked for a 7 hours.

I've checked the ceramic bearing. I've checked the impeller. I've checked the impeller housing. I have all the ends completely submerged in water so they can't pull air in. I've reseated the main gasket. I've gooped up the main gasket with silicone. I've moved the input/outputs around.

I did get this for basically free second hand. It was only used for a day or two. I can see why! So I can't just return it. I've got a new hose that I haven't tried yet thinking maybe the seal on the original hosing is bad or there's a small leak somewhere in the line. However, I did just recently notice that when I open the valve for the flow control a thin stream of water will shoot out the side of the valve block on the output end. I've attached a picture that shows where it comes out. I'm just wondering if that means the valve block is damaged or defective or if that's just a normal thing with the fluvals. I want to make sure its not that before I slice up the new hosing in what will probably be a futile attempt to fix the problem.

Any thoughts on what else could be wrong?

KeepNitReel · 09/29/2013, 02:58 PM

I have a 406 running on my QT & I have never seen water come out the part you circled in the pic.

00101 · 09/29/2013, 07:33 PM

The water only comes out when the valve is opened from low flow to high flow.

I also seem to have left out an important part. When its in 'air lock' it makes the worst rattling clicking noise. The hoses shake enough that the ends move around. And looking at the whole thing more closely, when it goes into 'air lock' it will sometimes recover, but no air will be expelled. Or if I just unplug it for a few seconds and the plug it back in it will pretty frequently recover, still expelling no air.

That leads me to think it might be an issue with the impeller assembly. But the blades show no damage or wear. The ceramic shaft shows no signs of wear either. I've spun the impeller on the shaft in my hand it seemed to spin freely with out rattling or anything. The impeller housing also shows no damage or scratching that would probably be there if the impeller was striking it.

00101 · 10/04/2013, 07:15 AM

Bump I guess....

KeepNitReel · 10/04/2013, 07:24 AM

Water doesn't come out mine no matter what, so I assume you have an issue with that piece

00101 · 10/04/2013, 07:35 AM

I see. Does it sound like there might be an impeller problem as well?

KeepNitReel · 10/04/2013, 08:25 AM

Sounds like that piece is the only problem and causing that noise to occur

00101 · 10/04/2013, 08:51 AM

I don't know... How would having a defect in the valve system cause the clicking and violet rattling?

KeepNitReel · 10/04/2013, 11:19 AM

I suppose air could be getting into the impeller assembly from the breach at the valve thingy

KeepNitReel · 10/04/2013, 11:21 AM

That would cause a violent rattling every time an air pocket got into the impeller assembly

KeepNitReel · 10/04/2013, 11:39 AM

These canisters are gravity feed, so that air breach is more than likely the cause of your problem

00101 · 10/04/2013, 06:14 PM

That could be... but then why is it when it recovers that it doesn't expel any air?

KeepNitReel · 10/04/2013, 06:45 PM

I'm just guessing here but I think what's going on when/how it recovers is the sweet spot is found. What I mean by that is, the assembly inadvertently gets in a position where no air is able to come in. Kind of like a car tire with a leak. When the hole in the tire is on the ground the leak stops but once the tire moves and the hole is no longer on the ground, the leak starts again.

Don't think I explained that very well, sounded better in my head.

09/29/2013, 02:58 PM	#2
KeepNitReel Registered Member Join Date: Mar 2013 Location: Henrico, Virginia Posts: 490	I have a 406 running on my QT & I have never seen water come out the part you circled in the pic.

09/29/2013, 07:33 PM	#3
00101 Registered Member Join Date: Dec 2012 Posts: 125	The water only comes out when the valve is opened from low flow to high flow. I also seem to have left out an important part. When its in 'air lock' it makes the worst rattling clicking noise. The hoses shake enough that the ends move around. And looking at the whole thing more closely, when it goes into 'air lock' it will sometimes recover, but no air will be expelled. Or if I just unplug it for a few seconds and the plug it back in it will pretty frequently recover, still expelling no air. That leads me to think it might be an issue with the impeller assembly. But the blades show no damage or wear. The ceramic shaft shows no signs of wear either. I've spun the impeller on the shaft in my hand it seemed to spin freely with out rattling or anything. The impeller housing also shows no damage or scratching that would probably be there if the impeller was striking it.

10/04/2013, 07:15 AM	#4
00101 Registered Member Join Date: Dec 2012 Posts: 125	Bump I guess....

10/04/2013, 07:24 AM	#5
KeepNitReel Registered Member Join Date: Mar 2013 Location: Henrico, Virginia Posts: 490	Water doesn't come out mine no matter what, so I assume you have an issue with that piece

10/04/2013, 07:35 AM	#6
00101 Registered Member Join Date: Dec 2012 Posts: 125	I see. Does it sound like there might be an impeller problem as well?

10/04/2013, 08:25 AM	#7
KeepNitReel Registered Member Join Date: Mar 2013 Location: Henrico, Virginia Posts: 490	Sounds like that piece is the only problem and causing that noise to occur

10/04/2013, 08:51 AM	#8
00101 Registered Member Join Date: Dec 2012 Posts: 125	I don't know... How would having a defect in the valve system cause the clicking and violet rattling?

10/04/2013, 11:19 AM	#9
KeepNitReel Registered Member Join Date: Mar 2013 Location: Henrico, Virginia Posts: 490	I suppose air could be getting into the impeller assembly from the breach at the valve thingy

10/04/2013, 11:21 AM	#10
KeepNitReel Registered Member Join Date: Mar 2013 Location: Henrico, Virginia Posts: 490	That would cause a violent rattling every time an air pocket got into the impeller assembly

10/04/2013, 11:39 AM	#11
KeepNitReel Registered Member Join Date: Mar 2013 Location: Henrico, Virginia Posts: 490	These canisters are gravity feed, so that air breach is more than likely the cause of your problem

10/04/2013, 06:14 PM	#12
00101 Registered Member Join Date: Dec 2012 Posts: 125	That could be... but then why is it when it recovers that it doesn't expel any air?

10/04/2013, 06:45 PM	#13
KeepNitReel Registered Member Join Date: Mar 2013 Location: Henrico, Virginia Posts: 490	I'm just guessing here but I think what's going on when/how it recovers is the sweet spot is found. What I mean by that is, the assembly inadvertently gets in a position where no air is able to come in. Kind of like a car tire with a leak. When the hole in the tire is on the ground the leak stops but once the tire moves and the hole is no longer on the ground, the leak starts again. Don't think I explained that very well, sounded better in my head.