Jandy Aquapure Service Code 120 Issues

[hustler]

Started receiving service error code 120 on a five year old Aquapure cell. Tried acidwash, but still didn't solve the problem (the DC cord looked fine). So I figured I would bite the bullet and purchased a new PLC700 kit with new cell, DC cable, and sensor.
I installed the unit yesterday and it was fine - no service code.
Went and checked it this morning, and the 120 code came back on (the cell is on and shows flow). About 20 minutes later, the service code vanished. About 15-20 minutes later, it came back on again.
I've noticed that it has been doing that all day today - on, off, on, off...
Any ideas?
HELP

 

[Bama Rambler]

Sounds like a problem with the reversing relay in the unit.

I can't remember but it seems like someone replaced the relay on a unit. I just can't remember if it was a Jandy or not.

 

[hustler]

So I turned off the unit (after reading that may be the issue), and turned it back on. Everything reset - seemed fine.

Within about 15 minutes, now it reads a 121 service code. What the heck!?!

One thing (I'm not sure if it matters), the old cell (tan colored/may have been a 1400) had three pins on top that the DC cord pushed onto. The new grey 700 unit only has two pins on top (even though the end of the two DC cords were identical where they plugged in inside the panel).

HELP - it's driving me crazy! I really don't want to have to call a service tech out (I'd like the satisfaction of knowing I solved the problem myself - with a little help from someone here at troublefreepool.com :-D ).

 

[hustler]

Now this morning, the 121's gone but it's back to the 120 code...

 

[hustler]

After testing the back board and cell, I found there to be 35 volts. However, I read there should be 22-28 volts coming from the back board.
Could this higher voltage be the issue that's causing the faults - and if so, is it as simple as replacing the back board?
Anyone...

 

[hustler]

Jandy Aquapure backboard question...

Topics Merged. This is a classic example where keeping all info in one topic would have made a difference in the advice given. Lets keep all the info in one topic. Bama

Does a cm601 backboard put out more voltage than a cm301?
Changed my cell from a 1400 to 700 and the PCB is putting out 35 volts (instead of the recommended 22-28 volts).
The PCB board in the unit now is the cm601 board (and I keep getting 120/121 service codes). Do I need to install a cm301 to get it to the recommended voltage?

 

[Bama Rambler]

Did you check the voltage out of the reversing relay?

 

[hustler]

Where exactly is the reversing relay?
I did check the voltage down at the cell, and it was about the same - 35 volts.

 

[Bama Rambler]

Was that with the cell power in both normal and reverse directions?

 

[hustler]

If you mean normal and reversing, I'll check it.

 

[hustler]

While cell is reversing, I get 35 volts at the cell and -35 volts at the backboard connections. Is this normal?
I still am receiving the 121 service code by the way...

 

[Bama Rambler]

That's normal as far as the plus and minus. All the relay does is reverse the polarity of the voltage to the cell plates.

Sounds like it may be the board that's the problem since it's a new cell.

 

[hustler]

So 35 volts is an issue and may be solved by replacing the backboard?
Should I buy the cm601 that's in the unit now (that was running a 1400 cell), or the cm301 (since I'm running a 700 cell)?

 

[Bama Rambler]

You didn't mention that you changed cell sizes. That makes everything you've done moot.

After reading a bit it appears that you can't just change cell sizes without changing the control module.

 

[hustler]

When you say control module, what are you referring to exactly?

 

[Bama Rambler]

It's what you're calling the backboard.

 

[hustler]

So whaddayathink, swap out the m601 backboard for the m301 and I should be good to go?

 

[Bama Rambler]

That appears to be the concensus of the stuff I've read.