Suction cleaner - pool pump always has large amount of air swirling.

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C

conmore

0
Jan 5, 2008
68
Geelong Australia
Hi there

I'll try and describe this issue as best as I can but to say it's frustrating me would be a huge understatement. I have an inground fibreglass pool 10 x 3M approx. 30,000 litres. Water chemistry is spot on and water is always crystal clear.

I inherited the pool with the house and with it included a Hydrosweep (now marketed as a Davey Leaf Wizard) suction cleaner as well as a new spare cleaner. It has always worked well and never given much trouble except for routine maintenance (replacing rubber wheels and kick rubber)

Of late I've noticed even though the cleaner is still working and moving at the recommended 22rpm there is a large amount of air in the pool pump. If I remove the fitting from the vacuum plate the air "bleeds" out quickly to zero air. Put the volume control fitting back into the vacuum plate and it starts sucking air again.

What I have done to overcome this problem:

Filters are regularly cleaned and sand filter regularly backwashed.
Replaced all the hoses (9 lengths) with genuine Davey hoses.
Installed a swivel to prevent hose kinking which has a weight on it to keep it submerged.
Replaced the large O ring on the underside of the vacuum plate even though its well under the water level.
Replaced the O ring in the pump lid.
Replaced the O ring on the suction side of the pump and checked all fittings for tightness.
Re-examined the volume control and turbine settings.
Given UP!!

The only other variable is the pool pump. Its been in service for at least 5 years with no leaks or problems but could it be the issue?

Just don't know where to go from here.
Any advice much appreciated.
Cheers
 
Attaching the suction cleaner increases the vacuum pressure on the suction side of the plumbing because the suction cleaner is more restrictive than the skimmer by itself. You should see filter pressure being a bit lower with the suction cleaner attached as the pump is using more of its energy to pull water from the pool.

The higher vacuum pressure will pull more air through any suction side leaks that might exist. I would have suggested the cleaner hose, because that's the most common issue, but you mention that it's new. I'd still focus on that to rule out a poor connection, bad hose or something. There may be a minor suction leak on the pool plumbing somewhere, which is worsened when the vacuum pressure is higher.

Take a look at this article to start ruling out sources of the leak: Pool School - Suction Side Air Leaks

I hope that's helpful and good luck sleuthing it out
 
Hi there
Thanks for the reply.

Is there an easy way to check the air tightness for want of a better description of the hoses. Some way to identify a pinhole or the like? AND how can you diagnose an issue with plumbing which is well underground? The suction side of the pump from the skimmer box protrudes from the concrete about 40cm to the pump fitting and then 20cm down into concrete? hate to think it might be underground.



Cheers
 
You can test the hose by draining the water out, sealing the ends well with tape or some other way that you find handy, and then pushing 1/2 a metre of hose down into the water and watching for bubbles. Slowly work your way along the hose keeping some under water and watching for bubbles as you go. Take your time.

The leak, if there is one, in your suction side plumbing is more likely to be related to a fitting or connection, so don't worry about it being underground until after you've ruled out above ground leaks or something near the skimmer.

And just in case, did you lubricate the pump and inlet side o-rings when you replaced them? If so, great. If not, pick up a small tube of silicone grease, pop the o-rings out and coat them with the lubricant, and then re-install.
 
Jezza said:
Sorry if this sounds like asking the obvious- what happens when the the pump runs without the suction cleaner connected -ie when it is in skimming mode?
Click to expand...

Hi there

All the air bleeds out of the pump very quickly and remains air free until I reconnect the sweeper.

Cheers

- - - Updated - - -

needsajet said:
You can test the hose by draining the water out, sealing the ends well with tape or some other way that you find handy, and then pushing 1/2 a metre of hose down into the water and watching for bubbles. Slowly work your way along the hose keeping some under water and watching for bubbles as you go. Take your time.

The leak, if there is one, in your suction side plumbing is more likely to be related to a fitting or connection, so don't worry about it being underground until after you've ruled out above ground leaks or something near the skimmer.

And just in case, did you lubricate the pump and inlet side o-rings when you replaced them? If so, great. If not, pick up a small tube of silicone grease, pop the o-rings out and coat them with the lubricant, and then re-install.
Click to expand...

Hi

Thanks again. I'll test the hoses tomorrow. Reminds of how we used to test inner tubes (remember them) for pin holes by pumping them up and submerging them in a trough of water.

Cheers
 
needsajet said:
I hope Jezza keeps an eye on the thread. If it's not the hose or the o-rings, we're going to need the help :)
Click to expand...

Hi there

Well, this morning I tooled around to find something I could use to plug both ends of each length of hose to keep it airtight while submerged and did. Tested each hose and NO air bubbles whatsoever. If I eased off the silicone plug I used in the female end air bubbles would release just to confirm air bubbles would definitely escape if there was a pinhole or the like. To a previous poster's comment, I always use silicone on all O rings after dismantling so that's another possible issue eliminated. As well this morning I used the old check your gas connection solution by painting soapy water on all the connections (there are 2, one where the PVC pipe enters the screw fitting on the pump and a 90 degree elbow before it disappears into concrete and it really didn't show anything.

The only other variable I have as information at this stage is: not long after we inherited the pool and for some time after, when I'd insert the conical shaped volume control into the vacuum plate, it would "slam" into the plate and would also take a bit of force to remove. I don't mean tugging on it with two hands but you would most certainly know something was working there suction wise. Now I feel its about 1/2 that effort both inserting and removing.

My thoughts at this stage are: if there is not an easy solution to this problem and although the sweeper continues to work while the pump pot has air swirling around the top of it I'm starting to consider it might be time for a robotic cleaner. Now there a can of worms. Which one? Need it to climb walls, Efficient etc etc

Thanks for your ongoing advice and help folks.

Cheers
 

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A bit of air swirling around after connecting a suction cleaner is not a concern so I'm just wondering, how much air stays in the pump basket? half air? quarter air? or just near the top?
 
Yep it's the messing around with suction cleaners that made me bite the bullet and upgrade to the robot. I am very impressed with the way it works despite the cost. Also happy to recommend the Davey Wallclimba which I've had for nearly a year now. It's a Davey badged version of a Maytronics cleaner, the mob that do the Dolphins but cheaper. Also comes with a 3 year warranty.

The only other thing that comes to mind is re-evaluating your process for purging the air out of the hose on start up. Also assuming that the volume control/vaccum plate is fully submerged under the water it's hard to see that being the problem. Does the bubble reduce in size over the run time or stay the same?
 
Jezza said:
Yep it's the messing around with suction cleaners that made me bite the bullet and upgrade to the robot. I am very impressed with the way it works despite the cost. Also happy to recommend the Davey Wallclimba which I've had for nearly a year now. It's a Davey badged version of a Maytronics cleaner, the mob that do the Dolphins but cheaper. Also comes with a 3 year warranty.

The only other thing that comes to mind is re-evaluating your process for purging the air out of the hose on start up. Also assuming that the volume control/vaccum plate is fully submerged under the water it's hard to see that being the problem. Does the bubble reduce in size over the run time or stay the same?
Click to expand...

Hi

Yes the plate and control are always well under the water line. And in the past the air would purge to a half fist sized bubble but now remains "cavitating" in the whole top of the pump pot.
All your help and advice is most appreciated but I've tried everything I could think of and double checked stuff from suggestions here to no avail.. in computer terminology - it's a glitch!!
My local pool store tried to sell me A Dolphin M500 which retails for $2200.00 aaargh!

Cheers
 
Do you have a skimmer plate something like this: Waterco Skimtrol Mk2 Skimmer (3 Poolshop.com.au

If so, here's a possibility to try...

Disconnect the vacuum and also open the skimmer plate bypass wide open (all the way toward slow)
Plug off the opening in the skimmer plate used to connect the suction cleaner
Gradually (but not completely of course) reduce the amount of water getting through the bypass, to simulate the restriction caused by the suction cleaner
If the air in the pump basket increases, then at least you would know there's a suction leak somewhere in the plumbing, and the problem is not related to the suction cleaner
 
OK, the other way then would be to use something to reduce the size of the hole. Something flat, plastic and sturdy, or a small piece of timber. Don't close the hole off completely, but gradually slide something across it that makes the hole smaller (maybe half of full size), but can't drop through or plug it off completely. Idea being to simulate the restriction caused by the cleaner and see if air accumulates in the pump.
 
needsajet said:
OK, the other way then would be to use something to reduce the size of the hole. Something flat, plastic and sturdy, or a small piece of timber. Don't close the hole off completely, but gradually slide something across it that makes the hole smaller (maybe half of full size), but can't drop through or plug it off completely. Idea being to simulate the restriction caused by the cleaner and see if air accumulates in the pump.
Click to expand...

Hi

Diagnosis complete I think. The hole on the plate is about 5cm in diameter and with a rigid piece of plastic about 3mm thick placed halfway over the hole no air is drawn into the pump as I gradually close the hole off from halfway air begins to enter the pump and at a little over 3/4 closed it exhibits the same behaviour as having the cleaner attached :(
So from that test I suppose I can assume the problem is between the skimmer box and the pump inlet connection..
Cheers
 
Seems like it, yep. That's too bad. You can recreate the test for checking the above-ground possibilities between skimmer and pump, but it sounds like you've already done a thorough job of that. Sometimes you can hear the air, so on a still day, I would listen at the skimmer and hope it's there. Another possibility is a buried check valve. It's pretty unusual for PVC pipe and fittings to develop a leak spontaneously. Problems are usually right after installation. Slip ground isn't good for pipe, are you on a big slope or anything?

I'm with Jezza if the suction leak ends up being in or under the concrete. A robot will be cheaper than jackhammers, and more satisfying!

If it were mine, I'd do a bucket test to make sure I'm not losing much water when the pump is off.
 
Hi
The pool is on a flat block as is the rest of the house. Funny you say listen at the skimmer because conducting the open and partial closure of the hole in the vacuum plate I reckon I could hear a kind of gurgling sound for want of a better description at the skimmer. Today was fine and no wind to speak of. I also put my ear to the first hose of the suction cleaner and can hear the same gurgling?
I'm pretty in tune with my pool :) I don't think it's losing water other than evaporation but I'll do the bucket test to be sure. If the issue is the skimmer connection, what's involved? And would be beyond my experience I think. Would an image help?
Cheers
 

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