SWG plumbing question

[H-12 1/2 Mike]

During another discussion yesterday one of the forum members got me thinking about the location of my ASTRAL35. I mentioned to him that I cannot run my pool at low rpm because the SWG would only be 3/4 full. I then checked my equipment and realized the SWG generator is about 6 inches higher than the highest point of my filter.
Is this an issue?
My original filter was much taller but was replaced several years ago with a shorter filter. I think is why the plumbing is located in a higher position.
If this is a problem, would you re-plumb or purchase the taller filter or just keep running at 2000 rpm to keep the cell full?

 

[Jimrahbe]

Mike,

I looked at the manual for your cell and see nothing about the water level in the cell itself. There is nothing about "must" be higher than all the other plumbing.. There is also nothing about ensuring the cell is '"full of water" before using, so it may not matter..

If this were my cell, I would make my decision about moving it based upon the amount of effort it would take. If all you need to do is cut a couple of pieces of PVC lower the cell and reconnect the PVC with a couple of adapters, then that is what I would do. If I had to re-plumb half the equipment pad just to make this work, then I doubt it is worth the effort.

At 1200 RPM my pump uses about 190 watts of power... at 2000 RPM, my pump uses 620 watts... so the cost to run the pump is about 3 times as much. That said, it cost so little to run the IntelliFlo, I'm not sure you would see a huge savings...

Show us a picture of your equipment pad and current cell installation.

It would be worth an e-mail to Astral and see what they have to say first..

Thanks,

Jim R.

 

[JamesW]

The Cell MUST be installed with the barrel unions underneath (water connections pointing downwards) and the cell should
be horizontal.

It is essential that pipe work and equipment do not allow gases generated from the cell to collect and build up.

WARNING: Cell must be installed horizontally with water connections pointing downwards – this creates a safety gas trap. Installation in any other way may cause explosion, injury or death.

WARNING: Cell must be installed in the return pipework to the pool. Always install after filter, gas heater, and solar heater or heat pump connections.

The cell uses a gas trap design instead of a flow switch.

This is mostly an Australian thing as it's required there.

There are two points in the cell that an electrical signal travels between conducted by the salt water.

If the water gets too low, the signal can't travel and the system interprets it as low flow.

The cell doesn't have to be higher than the other plumbing but it does need to be at the top of a loop so that gas can be trapped if there is no water flow.

The design does not work well at low flow.

Because it's at the top of a loop, any chlorine gas and hydrogen gas that are generated build up and need strong water flow to clear them from the cell.

Any air in the system will also accumulate in the cell and require more water flow to clear the gasses from the cell.

The design was made when pumps were mostly single speed 1 to 2 hp and 50 to 80 gpm.

That worked well for those pumps.

The introduction of variable speed pumps and low flow created a problem that the gas trap was not designed for.

If the cell plates are not fully covered with water, the production will be diminished and the cell might turn off due to a "low flow" warning.

US systems usually generate at a specific rate and turn on and off to control production.

Australian systems sometimes use variable power to control production.

At high production, more chlorine gas and hydrogen gas are produced and need more water flow to clear them out of the cell.

Some systems do specify "highest point".

"must be located above the highest point of plumbing."

http://www.sgschlorinators.com/wp-content/uploads/2016/04/Commercial-Owners-Manual.pdf

 

[H-12 1/2 Mike]

Thank you for the information Jimrahbe and JamesW. I also think that the cell is more efficient when it is 100% full. So, my plan is to run the pump @2000rpm for 8 hours instead of 1100 rpm for 24 hours. This should solve the cell issue without incurring any additional costs. It bothered me this summer when running at 1100 rpm and seeing the cell only 75% full even though it was still producing adequate chlorine at a 20% setting.