Pentair Sta-Rite header turns on by itself.

[pdpantages]

Hello Forum,

I have a Pentair Sta-rite Max-e-therm heater that will turn on by itself in the morning when the pool pump comes on.
I have seen other threads on similar issues with heaters (around 2016) and from these I can see:

- the heater may do this if the the heater is powered down ( when the timer turns off pool equipment) before its shut down procedure is complete (in response to a "heater off" button) .
- Some people have reported that a new control board did not fix this type of problem
- Some people have reported that a new membrane did fix the problem
- Others said they fixed it by ensuring the power remained on for 5mins or so after the pump was shut off

I noticed the problem last fall. It is possible that I did not let it shut down properly, but since I installed this header in 2015 I am surprised that I did not notice this behavior earlier. I do like to let the pump run for a bit after I shut the heater off, to cool everything down, so it is possible I suppose, that I had a perfect record regarding this procedure all the way up to last fall when I noticed this issue.

So I plan to do some experiments and see if I can reproduce the problem, and verify if the problem can be fixed by ensuring a correct shutdown of the heater. If this fails I will try a new membrane...

Heater Model: SR400NA
Control Board PN 42002-0007 REV C
Control Board SN 336388 DC1517
Control Board CPU has an R13 label on it

I would appreciate any insights from those who have had and fixed this particular issue. I will report my findings to this thread also.

Thank you PdP

 

[1poolman1]

The membrane is simply the "keyboard" to the computer, your user interface. Replacing it will not solve your problem. You must turn the heater off manually if you don't have automation. When the heater is turned off, the fan continues to run for a time to cool the heater. Leaving the pump on for that time is a better option. The heater "remembers" the last state it was in when the power is removed and re-starts in that condition.

 

[pdpantages]

The membrane is simply the "keyboard" to the computer, your user interface. Replacing it will not solve your problem. You must turn the heater off manually if you don't have automation. When the heater is turned off, the fan continues to run for a time to cool the heater. Leaving the pump on for that time is a better option. The heater "remembers" the last state it was in when the power is removed and re-starts in that condition.

Yes thank you for the reply. I understand what you are saying; but my problem is that when the heater is shut down properly, and the pump is turned off and on (cutting and restoring power to the heater) the heater re-lights. I.e, it is not correctly "remembering" the previous state of "heater off"...

 

[Poolbreh]

I’m interested in your findings, some ideas harmonics may play a role in it turning off and on, if there was a way to test for that, that would be cool. A $5 toggle switch hooked up to the fireman switch and mounted to the lid or ran to the wall should fix this problem. Good luck.

 

[pdpantages]

I’m interested in your findings, some ideas harmonics may play a role in it turning off and on, if there was a way to test for that, that would be cool. A $5 toggle switch hooked up to the fireman switch and mounted to the lid or ran to the wall should fix this problem. Good luck.

OK Thank you for the suggestion. Yes I will report any findings in this thread. For the switch I thought of putting an on/off switch inline with the 220V supply to the heater, but your idea might be a little less work and more neat/tidy.

I am not sure what you mean by harmonics- you mean I might have a 120 or 180 hertz component on my 220V power input? You didn't mean hysteresis did you?

Just fyi, since I am posting- my first test last night was to shut down the heater properly, left the power on for 1hr+ after heater-off button. So far this morning it has not restarted.

 

[Poolbreh]

Any kill switch should get it done, if it’s breaking the fireman switch or high voltage going in. Harmonics from the variable speed or pump capacitors that cause interference with gfci breaker may also be causing interference with heaters low circuitry. Often times filter pumps and heaters are on the same high voltage circuit. But this is all a guess.

 

[pdpantages]

Any kill switch should get it done, if it’s breaking the fireman switch or high voltage going in. Harmonics from the variable speed or pump capacitors that cause interference with gfci breaker may also be causing interference with heaters low circuitry. Often times filter pumps and heaters are on the same high voltage circuit. But this is all a guess.

Yes thank you. My heater is in fact on the same 220V circuit as the pump. I guess the best thing would be stick an oscilliscope on it (don't have a spectrum analyzer and see what it looks like with the motor running. My pump capacitor is not that old and was within spec in January when I checked it.

 

[ajw22]

I would replace the membrame keypad. The POOL key can be stuck ON or be intermittent causing the heater to run.

The harmonics idea is a wild long shot and not a path I would go down.

 

[Poolbreh]

I’m just saying, there are heaters where they replaced the board and membrane and continued to experience the same problem. This may not be the case with pdpantages it very well could be just the membrane or the board or some ants that decided their life goal was to become a circuit on pdpantages board . But those other cases? He seemed to want to dig deep. Allen would know better though. I think he planned on starting with membrane. I just thought if there is a mystery he may be able to find it. You can unplug the membrane and see if it stops.
Just throwing out ideas.

 

[ajw22]

I would exhaust other simpler fixes first.

Disconnecting the keypad is a good thought.