AquaPure 1400 service codes 120 121


Apr 6, 2009
I have had no problems with this system for 3 years. Upon getting some service codes I cleaned the cell, and went through all the checks posted on this site to check out the board and sensor. I have visually checked the DC cord terminals. The unit appears to work for a little less than an hour and then posts either service code 120 or 121. It doesn't appear to be generating chlorine, so I have been chlorinating the pool with liquid chlorine.

My first question,, what would be the way to check the "DC cord",, should I check it to the cell, or just pull the cord and ohm check it separately.

Second question,, should I continue to check the "DC cord" or should I be looking somewhere else



TFP Expert
Oct 12, 2008
Hillsborough, NC
A bit redundant, but I'd disconnect the cord, check the voltage on the supply side, test ohms across the cord conductors, and then double check the voltage on the cell side with it connected.


Apr 6, 2009
I checked the cable, it ohm'ed out fine.
I checked the voltage across the plugs and it was 48 volts,, which seems high. Could it mean that there is no conductivity across the cell?


Active member
Sep 3, 2008
I just recently had the same problem and had to get the entire cell and DC cord replaced.

Good thing it was under warranty, and I also ended up getting the newer designed, improved Jandy model 1400.

Good Luck.


In The Industry
May 22, 2009
If you're getting code 120/121, leave the DC cord on the cell, just pull it up a little (enough room to get a volt meter lead in) and check DC volts. Yes, 48 high it should normally be between 22-30 Volts DC.

Make sure the cord is pressed FIRMLY on the cell.
Remove & inspect cell. If it has calcium deposits on it, leaves, rocks etc (anything the filter and pump basket did not catch) then it need to be cleaned.

The following is directions from page 30 of the Aqua Pure Owners Manual:

Acid Wash Cleaning. If the electrolytic cell has a tendency to scale, it is recommended that every two
months the cell be removed and inspected for scale formation and/or debris. Some filters allow debris
to pass through to the cell which could lodge between the plates in the cell. A small amount of scale
formation is normal. If by looking through the cell it is observed that there is excessive scale formation
between the plates or debris is present, the cell must be cleaned as follows:
a. Use a high pressure jet of water from a garden hose. If the cell cannot be reasonably cleaned in
this manner, acid cleaning is necessary.
b. Remove the cell from the plumbing. Replace the cell with the spool piece, if necessary. Remove
the sensor from the port.
c. To acid clean the cell, plug the two adjacent ports. Mix one pint of muriatic acid with two quarts
of tap water in a plastic bucket. Use the appropriate port plugs on the ports. Do not use the
sensor as damage can result.
d. Pour the acid/water mixture inside the cell. A foaming action will begin, which is caused by
scale (calcium carbonate) being dissolved from the plates. If rigorous foaming action does not
begin, the cell does not need to be cleaned (STOP THE CLEANING PROCESS- go on to next
step “e”). Otherwise, allow the cell to remain in the solution until the foaming has stopped.
However, do not leave in acid for more than 1/2 hour. *(Excessive Acid Washing will damage
Electrolytic Cell).
e. Rinse the cell thoroughly with clean tap water and inspect. If deposits are still visible, repeat the
cleaning procedure. Additional acid may need to be added to the solution.
f. Rinse the cell again with clean tap water and inspect. If clean, replace the cell and resume normal
g. If the acid wash procedure is necessary, it is recommended that a sample of pool water be
analyzed by an authorized AquaPure service representative for excessive hardness and/or
improper water balance.
h. If no scale or debris deposits are observed in the cell after two bimonthly inspections, it is not
necessary to continue bimonthly inspections. However, due to possible changes in pool water
chemistry and filtering effectiveness, it is recommended that the cell be removed for inspection at
least twice a year.

Reinstall the cell. Wait 15 minutes and check to see if you are still getting an error code. If this does not fix the problem, then I would check voltage from the Back PCB Board. Refer to page 7 of your owners manual or the above link. If you don't have 22-30 Volts DC coming out of the Back PCB Board, BINGO, there is your problem.

More then likely replacing the Back PCB board will fix the problem. I've replaced twice as many Back boards as I have cells. The cells are VERY expensive to replace. If fact you can almost buy an entire unit for what the cell costs.

Joe Williams
Aqua Doctor
[email protected]


Apr 6, 2009
I found a very good diagnostic manual on the Jandy product. ... Manual.pdf

or find it by google'ing

Aqua Pure and PureLink Troubleshooting Manual.pdf

I went through the whole process, very similar to what was posted earlier, but with pictures and flow charts. The diagnosis was the cell is bad. I ordered a new one (new model) I found for $492. Best Price I could find, but included cable and sensor.

The net was, after cleaning, I get 24 volts on at both ends of the cord before plugging it in. When I plug it into the cell,, I get 48 volts across the cell. I guess the cell must generate current from the flowing saltwater.


Active member
Sep 3, 2008
I also noticed that after replacing my older Jandy 1400 model with the updated one that the salt sensor was WAY more sensitive than the model I replaced.

The old 1400 read 3900PPM salt in my pool, and the new unit read 4100/4200PPM (which is high)



In The Industry
May 22, 2009
mwbooth said:
I went through the whole process, very similar to what was posted earlier, but with pictures and flow charts. The diagnosis was the cell is bad. I ordered a new one (new model) I found for $492. Best Price I could find, but included cable and sensor.

The net was, after cleaning, I get 24 volts on at both ends of the cord before plugging it in. When I plug it into the cell,, I get 48 volts across the cell. I guess the cell must generate current from the flowing saltwater.
What a great price for a cell, is it a 700 or 1400 replacement cell? All the new cells come with 3 ports. IN/OUT/Sensor port. And yes they do come with new sensor and cables. Keep in mind the cell if properly cleaned and maintained should last at least 3 years, that's the warranty on them. The #1 thing that causes a cell to fail is improper water balancing. If your pH is high it will GREATLY shorten the life of your cell. Also per the owners manual and 1st hand knowledge. PLEASE, PLEASE by all means PLEASE turn your salt system off when adding salt to your pool, pour it in the deep end and allow the water to circulate for 24 hours, using the Main Drain line if at all possible.

You are correct about voltage across cell. A cell will fail when it becomes corroded. The fins inside the cell will become thin and the normal voltage will rise since there is less resistance. How the cell works is the voltage chemically splits a salt particle into two parts, Sodium (part of Baking Soda, hence the reason your skin is softer when you come out of a salt system pool) and Chloride Gas. The Chloride gas does it's job as a cleanser in the pool water, the two particles reunite and the process runs over & over again. The only ways to remove salt from a pool, are backwashing, a leaking pipe, overfilling the pool and it going out the overflow of the pool and via bathing suits. Yes folks the salt will be in your swimming suit.

On a side note about water chemistry with salt systems. Please check or have your pool water checked for cynaric acid levels. Since Chloride Gas is "unstablizied" you will lose it's efficiency if you don't manually add Cynaric Acid (aka Stabilizier). A good general rule of thumb is add 1/2 cup of Cynaric Acid every time you add a 40# bag of salt. Again if you turn off the salt system when you add the salt, this is a perfect time to add the Cynaric Acid. Cynaric Acid is the ONLY chemical you should ever add directly to your pool via the skimmer.


New member
May 2, 2010
Hello mwbooth,

Thanks for the manual! Also, I may need a new sensor. Any good suggestions on where to get a sensor for a good price?




Jul 21, 2010
Alexandria, VA Zone 7
Here is the link to the above mentioned reference. Great resource. I'm having the same trouble and will troubleshoot my system this week.
I have already acid washed my cell and didn't see any reaction. I have noticed white flaking off the cell which does wash away some with high pressure water. My Aquapure was installed in late 2005 and the cell is probably due to be replaced. ... Manual.pdf


New member
May 20, 2013
I too have been experiencing the 120/121 service codes. The cell wasn't making chlorine and wasn't showing flow of voltage to the cell. The cell is only about two years old (second one since 2005 when the pool was new). I went through the troubleshooting and averything pointed to the flow sensor. I changed the sensor and now have flow, however i am still geeting the codes. I have checked the chlorine level and the cell is definately making chlorine but the level is lower than it should be being at 100%. I checked the voltage and it is 35V at the board and at the cell. I have read that it sould be the back board and other places that it could be that i have unbalanced water (no stabilizer) or it could be the cell. I have also read that someone said that the cell generates the voltage, however i find this hard to believe. I was under the impression that the bakboard produces the voltage and the cell operates at between 22 and 28 volts. The troubleshooting manual sais it is the cell!
I don't want to spend the money for a new cell if it is just the backboard. I hope someone has the correct answers! How do i check the backboard?

Thanks in advance,


Well-known member
Aug 30, 2015
I know it is now 2016 but I have the same problem. Admins can point me to a newer thread if you can find one. The pool company came out and said it was possibly the transformer and if not that then I need an entire new system. Transfer and labor is near $500 and New system is $1500 plus labor. This is something I can NOT do myself. I'm thinking of just using chlorine tabs this year. It puts out some chlorine when on at 100% even low the code is Low forward current to cell. Anyone else had to live with tabs in the skimmer? TIA!!!