Rainbow Chlorinator Options for Commercial Pool

[jnastasi]

Hello Everyone!

Last year we had a PB come in and replace an existing Rainbow HC3330 with two new Rainbow 320 chlorinators. His rationalle was that we were much better off with two inline units (filtered water) as opposed to an offline unit (dirty water).

The problem is ... they never did work. Ended up using Cal Hypo all last year because the Rainbows never did put enough chlorine in the pool.

This weekend I figured out the problem.

On one of the two units the control value had stopped working (wouldn't turn off water flow), o-ring had deteriorated, etc ... so I just replaced it with a brand new Rainbow 320C (the clear amber version). It was cheap enough to leave the Tee in place and just replace everything else. I was also looking for an excuse to go with the clear version. Figured it would make everything easier to troubleshoot and maintain.

Well wouldn't you know ... the new unit tested great with the top off but the minute I screwed it on ... no water flow. Even turned up to 5 you could see there was absolutely nothing coming out of the valve. That explains why the units never worked last year.

My question(s)...

1) Installing the Hi Flo feeder kit seems to be an option that would solve the problem but, per Pentair, they want you to install it between the pump and filter. Wouldn't that just take you right back to putting dirty water into the chlorinator?

2) Am I truly better off with the two Rainbow 320s, or was I better off with the HC3330 we used to have?

3) Why is it that a majority of Pentair's chlorinators all seem to be of the offline variety? All of the commercial models (HC3315,HC3330,HC3340), for example, want you to install the intake in between pump and filter.

Appreciate any insight you guys might have to share. For reference it's a 100k gallon IG outdoor pool.

John

[PoolDoc]

You've got a sizing problem.

Locally, I've worked with large commercial pools for 25+ years. On a fairly heavily used commercial pool, you need a feed system capable of delivering at least 10 ppm of chlorine per day. On a 100,000 gallon pool using trichlor, that translates into 9 1/4 pounds of trichlor per day. Most days, you should use 1/3 to 1/2 of that. But, you'll need that 10ppm / day feed rate to keep up.

Installed out of the box, each RB320 can feed 0.67 lbs/day or 1.4 lbs/day combined. That's about 1 ppm per day -- not even enough to keep up on low load days. If you re-install with a top feed (long tube from box!), you'll score a capacity of 2.5 lbs/day, which is enough to keep up under ideal conditions. Of course, at that feed rate, you'll need to recharge the RB320's daily, since the feed rate diminishes as the number of tabs in the tube drops.

Of course, this assumes that the RB320 tees were installed correctly. They are directional, and I have often seen them installed backwards -- which leads directly to the "no flow" situation you describe.

By comparison, the HC3330 you replace stored 30# of trichlor (vs 4.5!) and has an individual feed rate of 4.5 lbs / day which is 80% higher than the maximum COMBINED output of the (2) RB320s.







http://www.pentairpool.com/pdfs/rainbow300DS.pdf

http://www.pentairpool.com/products/...eeders-140.htm