Air/gas in SWG with pump on low speed

[OzPool]

I just had another thought while watching my Polaris dance around the pool, which should have seemed bloody obvious to me before now If you look at my pipework in the photo above, in between the multi-port and the cell housing is an off-take for the Polaris. Obviously ( ) when the pump runs some of the flow is lost to the Polaris. I just checked on low speed and sure enough there is still some flow (not a lot but probably enough to be problematic) coming from the Polaris return. I now know what my first job will be on the weekend.

The Polaris is plumbed this way so that highly chlorinated water doesn't go through the booster pump, but it also means that un-chlorinated water is being returned to the pool. If I plumb the Polaris after the cell is it likely to cause a problem with the booster pump?

 

[Strannik]

if the pump shaft is exposed you would get higher shaft corrosion

 

[Bama Rambler]

The chlorinated water coming out of the cell is only a very small percentage higher than normal pool water, so the corrosion issue, while possible, isn't great. Also, the cleaner line isn't actually returning unchlorinated to the pool. It's returning normally chlorinated water to the pool.
But, stopping the flow through that line should help your problem.

 

[OzPool]

Will give it a go tomorrow and report back. Also, the installer got back to me and they have logged a warranty claim with the supplier. They mentioned there may be a problem with the polarity reversing on the cell - not sure exactly what they were referring to or how this would lead to the problem though?

 

[Strannik]

polarity reversing is a method of cleaning the scale of the cell plates automatically
basically the unit just reverses the polarity on electrodes, and positive plates become negative.

while it may be the case in your unit, it would have nothing to do with your issue

 

[OzPool]

Thanks, I understand the purpose of reversing the polarity, but like you I fail to see how it coiuld be related to this problem

 

[Strannik]

speaking of which, are your cell plates clean of scale?

 

[OzPool]

I believe so

 

[OzPool]

Tried shutting the valve on the Polaris return so that all pumped flow would go through the chlorinator cell. It didn't make any discernible difference to the flow in the cell housing and the bubble formed just as quickly.

I did manage to create another job for myself though when I forgot to re-open the valve . I got a nasty surprise when the booster pump started the next morning One lesson learnt the hard way! Several hours spent re-plumbing meant no time (or inclination) to try Mas's suggestion of trying to increase the flow by running the waterfall - maybe today.

 

[OzPool]

I tried opening the 3 way valve (as suggested by Mas) to return water via the returns and the waterfall. The waterfall hose is 1.25" flexible pvc. I dug it out and returned it to the pool at deck level so that I could see the flow. I then closed off the Polaris booster return (must remember to check that I opened it again):

With the 3 way valve open to both returns and waterfall hose - no change, still getting bubble formation in the same amount of time

With the 3 way open to the waterfall only - no change, still getting bubble formation.

With all flow returning to the pool via the 1.25" waterfall hose, I took some crude flow measurements using a bucket. Below are bucket measured flows and manufacturer's stated flow:

Low Speed - measured flow approx 70 Lpm (15 gpm), manufacturer's stated flow 121 Lpm (27 gpm)
Medium Speed - measured flow approx 110 Lpm (24 gpm), manufacturer's stated flow 212 Lpm (47gpm)
High Speed - not practical to measure

So does anyone have any thoughts on why I'm only getting just over 1/2 the manufacturer's claimed flow?

 

[JasonLion]

So does anyone have any thoughts on why I'm only getting just over 1/2 the manufacturer's claimed flow?

The simple answer is that pump flow rate claims never mean anything and should be ignored. Flow rates depend on almost every detail of your plumbing system and can not be predicted by the pump manufacturer. If they do give a flow rate it will always be for some wildly unrealistic situation that is ideal for the pump but impossible to duplicate in any practical installation.

 

[OzPool]

Still trying to nut this one out. I just replaced my spider gasket after noticing a leak to waste. The leak is still there but significantly reduced. I also noticed that there is a trickling/bubbling sound on the return side of the multi-port when the pump is running(regardless of speed). Could either of these things be related to the low flow issue?

Update: the leak to waste is still quite bad if I set the valve to re-circulate. There is about an inch of free play in the multi-port handle. I did pull the handle and diverter apart and lubed everything. The action feels pretty good, but I am able to lift the handle up by about an inch (without resistance) when it is position.