Rainbow 320 Problems

[TexasTwister]

I've been fighting 3 Rainbow 320 10-tab chlorinators all summer on 3 different pools :x. When the pumps shut off for the night, the water drains from the chlorinators. When the pumps turn on in the morning, none of the chlorinators refill with water.

Random information and thoughts:

• I have replaced the check valves in the bottom of the canisters on 2 of the 3 with no change in behavior
  I have replaced the lid gasket on 1 of the 3 with no change in behavior
  At my next weekly visit, either 9 or 10 of the tabs still remain
  Tabs are dry after turning off the valve, removing the lid, and the pump has been running
  On one of the Rainbows, I can hear an actual hiss of air either escaping from or entering the Rainbow when removing the lid (not sure which)
  On each of the 3, turning the valve from 'Off' to say 4 or 5, with the lid off and the pumps running, has water gushing into the canister
  As long as the canister is full of water (by letting it fill up with the lid off), it works fine until the pump shuts off

It is as though the Rainbows are suffering from some kind of vapor lock. My assumption is that the water is supposed to drain from the canisters when the system shuts off. The chlorinators even say on the side that when recharging them, turn the valve to 'Off' and shut off the pump for 1 minute to allow the water to drain from the canisters before removing the lid.

I can't think of any reason why these Rainbows will not fill back up with water when the pumps turn on in the morning. Any ideas? How does air enter the canisters in order for them to drain anyway? These 3 pools represent 75% of the pools I service that use these types of chlorinators. This leads me to believe it is something I might be doing wrong. The other pool that uses the Rainbow runs 24/7 and regularly uses up most of its tabs each week (it never has a chance to drain). Thanks!

 

[JohnT]

Rainbows won't fill if the flow is too low. Any chance these pools have dirty filters? Are they running 2-speed pumps on low? You need to have enough flow that the water can compress the air in the top. The Rainbow erodes the bottom tablets first, so it doesn't fully fill with water.

 

[Durk]

Is the feed tube connected at the top or the bottom? I believe the bottom connection is for 1" tabs and the top is for pucks. You need a longer tube to connect it at the top but it definitely works better hooked at the top.

It may have been installed with a flow reducer in the diverter--a soft, round reddish piece (at least in mine) that can be pulled out with your fingers once you unscrew and remove the main section. Check your spec sheet as to whether you want this in or not. It sure works better with it out.

You may want to blow out the regulator valve with compressed air. It's not just the check valve that gets gummed up.

I never use mine any more. I use LC in general and when I travel I use a floater with pucks. I needed way too much pump time with the Rainbow even when I had it working right.

 

[TexasTwister]

Wow! Great feedback! I learn something new every single day. It makes sense that the flow would need to be strong enough to force out the air but I never thought of it. The filters on these pools are maintained regularly (usually when PSI is up 8-10 over clean). I was unaware of the red flow reducer. I will have to pull one of these apart and take a look. All of these Rainbows have the fill tubes at the bottom of the canisters which I believe is appropriate for 3" tabs. All have a "gushing" flow if your have the lid off. With the lid on, it's a different story. Thanks for the input and if I come up with something, I'll post it here. Thanks everyone.