Peristaltic pump information moved from Chlorine forum

[fcfrey]

Now for some of the installation. A storm is coming so it may be short.

Hooking up the plumbing is pretty straightforward. The peristaltic pump, by its very nature will not back feed. In addition the injection port I used has a "Pop-it" type check valve built in. It works by actually requiring a greater pressure from the pump than on the other side in order to open and since it only goes one way it acts as a check valve. If the tubing comes loose or breaks the only consequence will be to pump the injection solution on to the ground at the rate the pump is set for.

Installing the port was only challenging because I wanted to locate it as far away from the other systems as possible. Definitely as far downstream of other chemical feed devises (erosion feeders etc,). I also wanted it to be out of the way so the port didn't get damaged. The port was 1/4 inch male pipe thread so I had to drill a hole of the proper size to accept the 1/4" pipe tap, in this case that drill size is 7/16". I also chose a location where I had multiple layers of PVC pipe to drill through (actually 3 fitting thickness). This gave a broad surface to tap and seal with Teflon tape.

The tubing to the pump and tank was just a matter of hooking up the tubing.
The only caution is to hook the tubing up to the proper sides (in and out).

Your local building code may require you to have a licensed electrician do the electrical work. Check the code in your area!!

The electrical was only challenging because everything beyond the breaker box at pool side is 220 VAC 2 wire with a ground. The pump was 110 VAC so there had to be a neutral. I have to preach a bit of National Electrical Code at this point. I'm not yelling but ----- NEUTRAL IS NOT GROUND. YOU MUST HAVE A NEUTRAL AND A GROUND. In addition NEC mandates NO OUTLETS WITHIN 10 FEET of the pool. I wanted to be able to unplug the pump and remove it for the winter and had the 10 feet from pool side. NEC also dictates these type things must be on a Ground Fault Circuit Interrupter (GFCI) breaker. This could be a problem if your pump is not on a GFCI (I installed a GFCI breaker on the main line at the house when I put the pool in so I was covered on that aspect. Things become a lot more complicated if you don't have the proper electrical facilities available. I'll explain how to overcome these obstacles if someone cares.

I had to pull a neutral from the box to the peristaltic pump outlet. I used one side of the pump feed after the last switch in the circuit so that the only time the peristaltic pump runs is when the pool circulating pump is running. This avoids building up a concentration of bleach in the return line. There is a switch on the peristaltic pump just in case you want to it shut off.

That's about it for installation so now it's Q&A time.

Next installment I'll touch on calibration and operation.

[Steve #1]

Plumbing the pump sounds easy enough.

I'm glad you pointed out the electrical side. I'll have to take a closer look at what I have there. I'm pretty good with low voltage DC but not so good with the household stuff. I'm going to switch the main pump and booster bump from using timers to connectors at the same time I do the injection. I'll probably get someone with more experience to help me with the electrical.

[Steve #1]

Well, it looks like this is coming together faster than I expected. I'm getting a 20-25 gal chemical drum from work, and Just picked up a Rola-Chem peristaltic chlorine pump on ebay for $32 shipped. Go figure, I finally find a great deal on a pump and it just so happens to be specifically for what I'm doing. I'm going to wait to see what all comes along with the pump before getting anything else, but worse case, I'll need a check valve, injector, and some tubing.

[fcfrey]

Steve,
Glad to hear your project is coming along.

I'll add this post on calibration of my system so you have an idea where to start.

Calibration of Peristaltic Pump:

First secure an accurate graduated cylinder > 200 ml and a stopwatch or other timing device so you can measure how much is being pumped over a period of time.

Start by dividing the speed control of the pump into equal divisions unless it has this done (mine did not). I then started the pump and counted the revolutions per minute and divided this by the number of lobes on the pump to determine how much is pumped per revolution or lobe cycle. Set the pump on each setting and time for 1 or 2 minutes recording how much is pumped.

Use these reading to figure the amount pumped in an hour. I created a spreadsheet to make my life easier. I then verified the calculations over an 8 hour period.

Using the bleach calculator I was able to figure out the PPM increase to expect for a given period of time (assuming no consumption from algae etc.). I did this at night to try to cancel the effects of solar burn off. I found I could predict the outcome accurately using this method.

The next thing I tried to do was calculate the PPM loss due to solar burn. This turned out to be a somewhat fruitless effort because of all the factors (clouds, date, water temp, pump run time, swimmer load, etc.) Needless to say I test very frequently (FAS-DPD method) and adjust the pump to keep the range within Ben's Best Guess Chart for my CYA level (around 22 ppm). After a period of time I was able to come up with some averages to work with.

I have since started increasing the CYA toward 30 ppm, to try to determine the best overall ratio. My daily CL burn off was about 2-4 ppm. if the pool is uncovered all day.

My experiment will continue for a year or two but things are favorable to this point. I may start looking at controllers if the price comes down but so far the cost/benefit ratio is still out of whack in my opinion. Any further questions --- please ask.

[nater]

Hey FC, I like your solar array! Very cool.

I use about 250' of black garden hose coiled up on the concrete when I need to add a few degrees. The BTU output on a hot and sunny South Carolina day is amazingly high....

Cool chlorine feeder as well. I love this home made McGyver stuff

[Steve #1]

Well, I got the pump and I'm not sure how it's going to work out. Rola-Chem had changed its model numbers and I couldn't find exact output for the pump I got, but it looked like it was the model for small to medium pools. Unfortunately its output is in line with there model for a large spa or for use as an acid pump for large pools. Output is 225 ML/Hr.

Based on my average consumption and normal pump run time, it should work for the most part.

I'm going to go ahead and set it up to see how it goes. If it can't keep up I'll just switch to a different pump.

[Steve #1]

OK, I'm set for everything except the electrical.

I got 2 60L (~16 Gal) chemical drums from work.

When buying tubbing, I was torn between clear vinyl and black vinyl. The black blocks UV, but would heat up more. I went with the clear since it was cheaper and plan to run it inside some 1/2" PVC I have on hand. This will reduce heat and UV exposure along with giving it some protection from dogs, kids, etc.

I am considering digging a hole and partly berrying the storage drum to reduce the effects of heat. The area where it will be is almost 100% shaded (between a shed and the house) so I haven't decided if it is worth the effort.

I had to buy a tap for my injector. I couldn't get a firm answer from either the hardware guy or the plumbing guy at Lowes if it was the right one or not. What I'm using as the injector is 1/4" MIP. The tap is 1/4" 18 NPT. After doing some research I'm 95% sure this is right, but I got a 1 1/2" PVC coupler to practice tapping just to be sure.

I should have this ready to go tonight.

I don't think it's much of an issue, but I'm going to order a check valve to install at the injector.

Now the electrical. The pool pump and booster pump are 240V and have intermatic timers. Ultimately these will be changed to connectors controlled by the home automation system, but that's down the road.

The Rola-chem pump doesn't have a normal flow rate adjustment. It has a timer that will run for a time (adjustable) then shut off for a time (relative to the run time).

I'd like to set up the injector pump so that it only has power when the pool pump is running. Is it possible (safely) to step down the 240 to 120 after the pump timer?

My other options for electrical are:
Running 140 from my bathroom vanity to the other side of the wall. Possible downsides to this are that the bathroom isn't on a GFCI (which should probably be updated anyway), and the outside wall is brick.

There is a switch and a timer for landscape lighting in the back corner of the yard. I have no idea where it runs from or what else is connected to it. I went to take look at it a bit ago and the ants informed me that it made a comfortable home, but agreed to move out.

Any opinions or criticisms are welcome.