How To Install an In-Line Salt Chlorine Generator


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This guide provides a step-by-step procedure for installing a typical in-line salt chlorine generator. Note: This guide is intended to give you a visual reference to supplement the manufacturer's owner's manual, not replace it. Make sure you read and understand your owner's manual before installing your unit. It will have the most up to date and manufacturer-specific information. An in-line salt chlorine generator generally has two parts: the power unit that supplies DC power for electrolysis, and the in-line electrolytic cell which converts diluted saltwater to chlorine (hypochlorous acid). Some units also have an external flow meter to detect if no water is flowing through the pipe. Although this guide is written with specific references to installing a Compupool Salt Chlorine Generator, most steps can be applied to any in-line salt generator. Also, this guide is written for an inground pool installation. If you have an above ground pool, see the comment, "Above Ground Pools", at end

Step by Step


Step 1

Your first step is to make sure you have all the items you will need to install your new salt chlorine generator. These will include: items to mount the Control Unit - level, drill, screwdriver; items to wire the Control Unit - voltage meter, screwdriver, wire cutters; items to install the Cell into the piping - hacksaw, file, pvc primer & glue, couplings, cleaning rag.

Step 2

Your next step will be mounting the Control Unit onto the wall close to the pool timer. Make sure that this location is at least 10 feet from the edge of the pool and that the 6 foot DC power cord connected to the Control Unit can reach the section of pipe selected to mount the Cell. The Cell has to be mounted at the end of the return pipe after all other units (i.e. after pump, filter and heater if you have one). In this case we will be replacing an existing Tablet Chlorinator with a Salt Chlorine Generator Cell.

Step 3

Mount the Control Unit bracket at eye level on the wall and, if possible, in an area out of direct weather and sunlight. We are using a level here to line up the bracket.

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Step 4

Place the Control Unit onto the bracket and secure temporarily with 2 screws.

Step 5

Your next step is to wire the power cord from the Control Unit to the pool timer. When wiring, be sure to follow local and NEC/CEC electrical codes. CONTACT A PROFESSIONAL ELECTRICIAN IF YOU ARE UNCOMFORTABLE WORKING WITH POWER. Incorrect wiring can cause dangerous shocks and may void your warranty.

Step 6

Before wiring, you will have to check the output power level at the timer going to your pump. It will be either 120VAC or 240VAC. In preparation for measuring your power, TURN OFF THE POWER TO THE TIMER BOX. There should be a circuit breaker before the timer box.

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Step 7

WITH POWER OFF, remove the cover over the screw connectors inside the timer box.

Step 8

This picture shows the wiring inside the timer box. Three wires come in from the left of the box. Two are labeled INPUT and one GROUND. Generally, but not always, color of the wire is significant. If the two INPUT wires are red and black, they are both load wires and provide 240VAC. If they are white and black, white is neutral and black provides 120VAC. The green wires provide GROUND. There are 5 terminals in the timer box. The left most, labeled “A”, is NOT USED. The other four are labeled 1 to 4. The INPUT wires are connected to 1 and 3.The GROUND wire SHOULD BE ATTACHED TO THE GROUND SCREW JUST ABOVE TERMINAL "A". IT IS WRONGLY SHOWN IN THE CURRENT PICTURE AS GOING TO "A".The OUTPUT wires are attached to 2 and 4. The OUTPUT wires are currently wired to the pump.

Step 9

To measure your voltage level, TURN ON POWER back on at circuit breaker. Set your digital multimeter to 300 VAC and place the meter's probes on the OUTPUT terminals, 2 and 4. It does not matter which probe is placed on which terminal. Be careful not to let the probes short out between two adjacent terminals. The meter should read close to 240VAC if your power is 240VAC - 120VAC if the timer is using 120VAC.

Click here to view the multimeter. 

Step 10

TURN OFF POWER at the breaker and replace the cover.

Step 11

Now you must check how your Control Unit is configured internally. Your Control Unit can be set to operate at either 120VAC or 240VAC to match your voltage at the timer. Control Units are generally shipped from factory in 240VAC configuration. If your timer power is 120VAC you will have to change the VAC power configuration within the Control Unit from 240 to 120. Each manufacturer has their own power configuration. If you are not installing a Compupool Control Unit, see the manufacturer's wiring guide for instructions on internal wiring of the Control Unit

Step 12

To check the configuration of your Control Unit, take the Control Unit off the bracket and take off the Control Unit cover by removing the 6 screws on the base of the unit.

Step 13

If you are installing a Compupool Control Unit and your output timer power is 240VAC, the 240VAC configuration should look like this. The key connections that make this 240VAC are red wire to J12 and orange wire to J8.

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Step 14

If you are installing a Compupool Control Unit and your output timer power is 120VAC, the 120VAC configuration should be changed to look like this. For 120VAC the red wire goes to J11 and orange wire goes to J14.

Step 15

Replace and secure the Control Unit cover with the 6 screws. Remount the Control Unit onto its bracket and secure with 4 screws.

Step 16

Your next step is to wire the power cord from the Control Unit to the timer box as show in the picture at left. Red wire to terminal 2, black to terminal 4 and green to GROUND.

Step 17

Attach a minimum 8 AWG copper wire between the bonding lug on the outside of the Control Unit and your pool bonding system. This system should already be in place for your pump. If you are installing a Compupool Control Unit, this bonding lug is shown at the left. Failure to adequately bond your power unit can lead to severe electrical shocks. Note: This bonding wire is installed in addition to your normal grounding process (green wire). You need both per code.

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Step 18

You can test the Control Unit now before installing the Cell. Do this test WITHOUT connecting the DC power line to the Cell. Turn POWER ON to the Control Box at the timer box - pump will go on also. The Control Unit lights will go on momentarily then off. Push the ON/OFF button on the Control Unit to turn the Control Unit ON. See Operator's Guide , to test out the rest of the Control Unit functions.

Step 19

Your next step is to install the in-line cell. The Cell has to be mounted horizontally and should be placed as the last element in the return line after the pump, filter and heater, if you have one.

Step 20

The Cell should be mounted with the inlet and outlet ports facing down. These ports are marked. Water should flow into the "INLET" port and out though the "OUTLET" port.

Step 21

Make sure the barrel unions are screwed tightly to the cell. Hand Tighten.

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Step 22

Cut two sections of pipe about 10". You can buy a large PVC pipe cutter that make a clean straight cut or you can use a regular hacksaw. Just remember to make as square a cut as possible.

Step 23

Debur and clean the outside and inside edges of the two pipes. A file with one side flat and one side round works well.

Step 24

Glue the 10" pipes to the barrel unions. Make sure the pipe and inside of the union are clean. Gluing is a two step process. First apply a thin but even coat of purple primer on each surface to be joined: the outside of the pipe and the inside of the union. After the primer has dried, apply a THIN EVEN coat of glue to both surfaces. Immediately push the pipe all the way into the union and twist 1/4 turn to spread the glue. Hold the pipe in place for 30 seconds until the glue sets. Repeat for the other union.

Step 25

Place 90-degree elbows onto the ends of the two 10" pipes as shown. Do not glue them on. These are placed on to determine how much of a space to cut out of your return line.

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Step 26

Measure the distance between the ends of the elbows. It should be 9". Remember that your return pipe will slide inside each elbow 1 3/8" so subtract 2 3/4" off your space measurement. This leaves 6 1/4" for the space to be cut out of the return line. This Cell is part of the larger CPSC36 unit. If you are installing the CPSC24 unit, the space may be shorter.

Step 27

TURN OFF POWER to the Control Unit and pump at the breaker box. Relieve water pressure in the line at the relief valve on the filter.

Step 28

Assuming that you are replacing an existing chlorinator with the salt chlorine generation cell, cut out the existing chlorinator so that there is a 6 1/4" space between the ends of the return line. Depending on your current configuration. you may have to cut out more pipe and then rebuild the piping so that a gap of 6 1/4" is left to install the new Cell.

Step 29

Now comes the tricky part. You have to glue two elbows on the ends of the return piping and place the pipes coming out of the Cell into the elbows before they dry. By steps - prep each elbow and return pipe end with primer and glue.

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Step 30

Place the elbows on the return pipes and push them on all the way.

Step 31

Quickly place the pipes from the Cell into the other end of the elbows to make sure the elbows are aligned and spaced correctly with the Cell pipe. The Cell pipes don't have to go on all the way - about 1/2" to 3/4" is sufficient. Just far enough to ensure that the fittings are aligned. Hold them there for another minute to let the glue set.

Step 32

Now take the Cell pipes out of the elbows and apply primer and glue to the Cell pipes and the unglued sides of the elbows. Push the Cell pipes onto the elbows all the way in and hold a couple of minutes until they dry.

Step 33

Wait two hours to let the glue joints fully cure before running water through the piping.

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Step 34

Attach the cell plug. Make sure it is pushed on completely as shown at left.

Step 35

Your salt generator cell is ready for operation. Make sure the pump is primed and TURN POWER ON at the breaker box to the pump and Control Unit . If the Control Unit isn't On, turn it ON at the Control Unit.

Step 36

Next you want to add salt to your pool for the Salt Chlorine Generator to act on. The Compupool CPSC/CPA Series is recommended to run at a salt concentration of 3500 ppm. If you are not installing a Compupool unit, check your manufacturer's instructions for their recommended level of concentration . Use a salt that is at least 99.8% pure NaCl. The preferred salt is an evaporated, granulated, food quality, NON-iodized salt. Avoid using salt with anti-caking agents like sodium ferrocyanide, also known as yellow YPS (prussiate of soda. These cause some discoloration of fittings and pool surface finishes. DO NOT use calcium chloride.

Step 37

Using a saltwater test strip, measure the current salt level of your pool. For the Compupool generators, the ideal is 3500 ppm. If the level is low, determine the number of gallons in your pool and add salt according to the Salt Table. For example, if your pool has 15,000 gals of water and your current salt level is 2500, you need to add 125 lbs of salt.

Click here to view salt test kits. 

Step 38

Before adding salt to your pool, be sure to TURN OFF the salt chlorine generator at the Control Unit. The generator should not be turned on until the salt is completely dissolved. Leave the PUMP ON to circulate the water and help dissolve the salt.

Step 39

When you add salt, DO NOT pour it directly into the skimmer. For best results empty the required salt into the shallow end of the pool and let it dissolve and circulate through the main drain. The salt may take about 24 hours to dissolve completely. Finer grades of salt will dissolve faster.

Step 40

After the salt has dissolved, turn on the salt chlorinator. Check to see that the salt level is around 3500 ppm. Your pool should be maintained at around this level. A low salt level below 3000 ppm reduces the efficiency of the salt generator which results in low chlorine production. A high salt level above 4500 ppm can rapidly reduce the longevity of the cell. See Operator's Guide , for further instructions.

Step 41

Picture of the completed Compupool Salt Chlorine Generator installation.

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(1 to 40 of 51)

InyoPools Product Specialist  Posted: 6/19/2014 

Compupool SCG - Check that your SCG connections are tight. If you have the old plug version, close the female terminals slightly for better contacts. If no success, call Compupool at 888-989-7258 to help you troubleshoot the system. The SCG is generally run off the same timer that controls your pump assuming they are the same voltage. And these SCGs are designed to operate at low speeds.

Anonymous  Posted: 6/19/2014 

We have an above ground chlorine-treated swimming pool. Recently, we bought a compu pool salt system from the person who has in-ground pool. We installed the salt system, we put the right amount of salt and after a certain hours of dissolving that salt, we started the control unit. In the control unit it shows me the time 100%, in the bottle its marked Idle and the polarity light, it doesn't light. I just wanted to ask if I did any mistakes with the installation or if the system doesn't work from before and we don't have timer on the salt system. Do we have to buy one?
Also, our pump is working with 2 speeds. Is the system going to work if the pumps are working in low speed?

Thank you.


InyoPools Product Specialist  Posted: 3/10/2014 

Stoney - According to our Intermatic rep, there is no problem with wiring both the pump and the CPX to the same circuit so you know they go on/off together. Still working on your question on CPX Chlorine output.

 Posted: 3/9/2014 

That's exactly what I was thinking--almost immediately after I posted the comment. My one other question is about specs for the CPX36. Mainly, what is the expected daily Chlorine output for this model? I can't find that info on any site I'm looking at. I know you don't carry them, but the circupool Si45 is speced at 2lbs/day. And , BTW. Thanks for your help!!

InyoPools Product Specialist  Posted: 3/9/2014 

Stoney - My thought on this is that you should be able to connect both the pump and the CPX to the same circuit so you are insured that the CPX is in sync with the pump. My only concern is whether or not the circuit can handle the current from both products. I will check with the mfr tomorrow and amend this response. As for your last comment, there is an ON/OFF button on the CPX control unit which would allow you to shut off the CPX while the pump is running.

 Posted: 3/9/2014 

After more thought, I guess a good reason for wiring it to circuit 2 spells be best so I can turn it off before adding salt independently of running the pump.

 Posted: 3/8/2014 

That may be a little late. Maybe you can help with how to wire the control unit to an Intermatic P1353ME digital timer in mode 3. The filter pump is wired to circuit 1 and the boost pump to circuit 3. Circuit 2 is not in use. Intermatic suggests I wire it to circuit 2 and just set the run time to the same as circuit 1. I would think I could just wire it to circuit 1 and have the cpx run at precisely the same time as the filter pump?

InyoPools Product Specialist  Posted: 3/7/2014 

Stoney - We may have a guide written for a CPX24 within a month.

 Posted: 3/6/2014 

Is there any way to have a new/modified installation guide for the CPX 24?

InyoPools Product Specialist  Posted: 7/10/2013 

knd - The installation for a AG pool is basically the same with a couple of differences. The AG model has a receptacle at the bottom for a pump plug instead of wiring the pump to the timer. The power to AG pools is generally 115V. And the plumbing will probably a mixture of hard and flexible tubing.

 Posted: 7/8/2013 

I dont see the comment for the above ground pool. I have the cpsc24-ag model its for an above ground pool do I install it the same way

InyoPools Product Specialist  Posted: 10/2/2012 

Redwar1 - Yes, There are different Salt Chlorine Generator models for each size pool. For example Compupool sells 4 models; CPSC16 for pools up to 20,000 gallons; CPSC24 - up to 26,000 gallons; CPSC36 - up to 40,000 gallons; and CPSC48 - up to 60,000 gallons. The main difference between these models is the number of plates in the cell used to generate chlorine.

 Posted: 9/29/2012 

When converting to salt water is the a certain size salt chlorine generaator for the size of the pool

InyoPools Product Specialist  Posted: 8/6/2012 

Henry1 - If this is an Compupool Salt Chlorine Generator, give Compupool a call at 888-989-7258. They will be glad to help you.

 Posted: 8/4/2012 

I ordered a new salt cell and installed it exactly like the original. The original stoped generating chlorine and would not read temp. It seems that the new one is doing the same thing, where do I go next? ,What do I check next? The unit was just over a year old and I hate to have to change to another brand of unit.

InyoPools Product Specialist  Posted: 7/31/2012 

pronto1 - Before you buy a new circuit breaker, call Compupool first at 888-989-7258. It might just be a matter of tightening the connections. And I'm confused about not finding the circuit breaker. I've seen them in a number of hardware stores.

 Posted: 7/31/2012 

I have a cpsc24 and circuit breaker pops on a daily basis, I cleaned the wire contacts going into the cell and it stopped popping for a while, just started again i think the breaker is weak and needs replacing do you have them can't find them anywhere

InyoPools Product Specialist  Posted: 7/17/2012 

keyboard - Give Compupool at 888-989-7258 a call on this one. Their technical staff will give you the information you need.

Anonymous  Posted: 7/16/2012 

I was shippped a new keypad because the old one didn't work. How do I install it

InyoPools Product Specialist  Posted: 6/12/2012 

Suzy Q - Sorry for the delay. Your cell should be full when operating otherwise it will heat up more than it should. A little bubble at the end might be all right but you should not operate the cell if it is only 3/4 full. Sounds like your do not have sufficient flow in your system. If you have a 2 speed or variable speed motor, you have to operate at a higher speed. If you have a single speed motor, your motor is too small for your system or you have one or more leaks in the system. See our guide on identifying leaks:


 Posted: 6/7/2012 

Does the electrode cell need to be complete full of water when operational? My cell has water to the top of the plates but does not fill the cell. Bubbles form on the outlet side of the cell. Is this normal? Will this damage my system? If wrong, how do I correct the problem? Thanks

 Posted: 5/30/2012 

The instructions say it should be on a GFI protected circuit do I have to replace my breaker WIRING
Refer to the wiring diagram below to determine correct wiring
connections. The CPSC/CPA Series is shipped from the factory
with the configuration jumpers in 240VAC position. If using
120VAC, move the jumpers as shown below. For Canadian
models, the CPSC/CPA Series shall be connected to a circuit
protected by a class A ground fault interrupter. Be sure to
connect the ground wire to the green ground screw terminal
located on the bottom of the enclosure.


Anonymous  Posted: 5/16/2012 

Starting my third year with my compu-pool salt chlorine generator. I am unable to turn the unit off and on using the touch pad on the unit. It is wired to come on only when the pool pump comes on, but the control pad only has limited functionality. It flashes in the winter mode but won't allow me to change this setting to another period. Is there a hardware reset that may allow me to return to default setting and allow me to reprogram. Also the chlorine level seems to defaut to lowest setting every time the power is turned off by my pool pump timer. Any suggestions?????

InyoPools Product Specialist  Posted: 5/6/2012 

Daniel - The How To Guide was based just like your set up; running off the pump's timer. All we had to change was the two wires you changed.I will check with Compupool Monday to see if anything has changed.

 Posted: 5/5/2012 

My CPSC36 arrived yesterday and I'm installing it today. I connected the red wire to J11 and the orange wire to J14 for the 120 v application. I plan to use the pump timer to start and stop the unit. Do I ignore the diagram showing connections at J1 and J5. Thanks.


InyoPools Product Specialist  Posted: 2/2/2012 

Shanek - The internal timers are setup through programming not wiring. See step 3 of our guide, "How To Operate a Compupool Salt Chlorine Generator". If that does not help, please call Compupool direct at 1-888-989-7258. One word of caution. However you set this up, make sure your pump is running and water is flowing through the system when you turn your Compupool Salt Chlorine Generator on.

 Posted: 2/1/2012 

Does anyone have a wiring diagram of how to have the unit control my pump so i dont need an external timer?

I cant find it anywhere.


InyoPools Product Specialist  Posted: 12/6/2011 

Many people have successfully used this guide to install their Salt Chloring Generator. Recheck your wiring against the guide to insure wires aren't crossed. If you are still unsuccessful, you may have to check with an electrician.

 Posted: 12/4/2011 

all is hook up like shown but when turned on the circuit breaker blows a fuse

InyoPools Product Specialist  Posted: 11/17/2011 

Dan, For 120V going from control box to supply, the black line is hot (load) and the red line is neutral. Green of course goes to ground.

 Posted: 11/15/2011 

For the 120V connection where do I go with the red wire for electrical supply - to neutral or another hot? Thanks Dan

InyoPools Product Specialist  Posted: 9/23/2011 

According to the manufacturer, it is common for the controller box to be hot during operation. Because of the transformer inside, it can reach temperatures of 180 degrees in the summer.

Anonymous  Posted: 9/22/2011 

I want to know how hot is the controller box supposed to get when the unit is running. The one I have gets pretty hot


InyoPools Product Specialist  Posted: 9/11/2011 

Your pool repair man is correct. A salt chlorine generator has to be installed as the last element in your return line after the pump, filter and heater. See Step 19 of our How To Guide.

 Posted: 9/9/2011 

I was just advised by a pool repair company that my chlorine generator on my salt pool was installed incorrectly. The chlorine generator is installed prior to the water flow going into my heater. He indicated that the chlorine generator should be installed after the water comes out of the heater and prior to going back to the pool in order to avoid damaging the heater elements. He also indicated that this setup voids the warranty on the heater and I could ask for a new heater from the company that originally installed the pool as well as request a re-plumbing of the chlorine generator.

InyoPools Product Specialist  Posted: 8/31/2011 

Sounds like your not wired to the timer correctly. Recheck the guide. If your are wired with the pump, they will both go on/off at the same time.

 Posted: 8/28/2011 

I just installed my compupool 60k, But I ran into problem. when my pump turns on, the compupool control unit turns of. Only when the pump turns off when the display shows up? Any possible solution?

InyoPools Product Specialist  Posted: 8/12/2011 

The primary concern when providing power to the Compupool is that you never run the Compupool without the pump being on. That being said, there are two general setups for installing the Compupool system. This guide assumes the most common set up for in ground pools where you have an external timer controlling the pump. For many above ground pools without an external timer, the user may choose to use the internal timer feature available on the Compupool system to control both his Compupool and pump. In this case the user would wire the Compupool direct to the circuit breaker and plug in his pump at the bottom of the Compupool control box. When the Compupool is installed you will set the display clock and the internal timer will be set to work off that clock. The internal timer will then turn on both your pump and Compupool at the time you program.

 Posted: 8/12/2011 

How are all of the added functions of the Compupool CPSC24 supposed to operate if the control unit is wired to the timer that turns the pump on and off? I have read everything I can find on this subject, and it seems to be very contradictory. If you are supposed to set the time and all the other functions, then how can it operate if the power from the timer keeps going on and off with the pump. Please respond to this comment, I see so many that are never answered.

InyoPools Product Specialist  Posted: 7/31/2011 

The salt will dissolve in 48 hours. If your water is cloudy after that, you have another problem and you may need to add chemicals to eliminate the cloudy condition. See our How To Guide on adding chemicals.