Aqua Rite - should current limiter get VERY hot

[tphaggerty]

I tried to replace the current limiter on my old (2004) Aqua Rite, it worked for a few minutes but then I got a PCB message.

Bought a new PCB on amazon. Just installed. Everything seems to be working, generating chlorine, the numbers look good etc. However, I touched the black current limiter and it is HOT. Very hot, probably hot enough to melt wire shielding. It is driving a Compupool replacement cell. (the new PCB is setup for a t-15 cell, which is what I have).

Anyone have the same experience? Any thoughts? Should I turn it off.

I thinking I might try the old cell just to see if that might still be working. I'm about to leave for a few hours, so I'm thinking I will shut if off to be on the safe side.

 

[JamesW]

The AS32 2R025 will get up to 428 °F at its full current rating of 25 amps. However, there should not be that much current going through the thermistor while operating. It is designed to heat up while operating, so it does get hot. I don't know exactly how hot. You might want to contact the manufacturer to find out.

Body Temperature @ 100% Current rating = 220 °C (428 °F)
http://media.digikey.com/PDF/Data%20She ... 22R025.pdf

http://dkc1.digikey.com/us/en/tod/Ameth ... Audio.html

http://www.ametherm.com/

Do you have a question about Ametherm's inrush current limiting power thermistors?
http://www.ametherm.com/have-a-question

 

[tphaggerty]

Well, that makes me feel somewhat better. It's definitely not THAT hot, I can touch it for a second or so. I just remembered that I have an infrared thermometer (somewhere). I think I'll dig it out and see.

What has me a bit worried is that the whole box gets hot and the sheathing on the wires closest to the limiter get warm and definitely more pliable. I would baby sit it for an hour or two if I had the time, will have to wait until tomorrow I guess.

Thank you so much for the quick reply! Where else but TFP!!

 

[JamesW]

I have noticed that some boxes do get quite warm. I will see if I can get some temperature readings from boxes and thermisters for comparison.

 

[johnd13]

I tried to replace the current limiter on my old (2004) Aqua Rite, it worked for a few minutes but then I got a PCB message.

Kinda funny, same thing happened to me. I'd read the threads on here about how easy a fix it was, so I got the part and replaced the current limiter on my old 2004 board and same issue so I had to order an new one Monday. At least I'll have taking the board off and on down pat...lol

 

[tphaggerty]

I wonder if the older boards can handle a new cell, especially after 7 or 8 years.

I did get a chance to turn it on this morning and took some temp readings with my infrared thermo. The current limiter ranged from about 120 degrees to as much as 220 degrees or so. The metal pad that it is soldered to (on the new board) went as high as 250 degrees. The rest of the board appeared to stay much cooler. Seems like very hot to me for electronic equipment, but maybe not - the box has always gotten very hot. No wonder the limiter burns itself up after a while!

I left it running today with the front cover off and the door open, if everything is still running when I get home, then I'll close it up. If not...

 

[JamesW]

Note that anytime you shut off the box, you should allow at least a minute or more for the limiter to cool down before starting it back up. The limiter only provides protection if it's cool.

 

[blueman2]

Note that anytime you shut off the box, you should allow at least a minute or more for the limiter to cool down before starting it back up. The limiter only provides protection if it's cool.

Excellent point. The purpose of the current limiter is to prevent damaging initial inrush of current. It does this by limiting current when cool (normal startup) and gradually increasing current as the part heats up. But it if is already hot on startup, it will allow a spike.

I am surprised there is no warning on the system about this.

 

[tphaggerty]

I never thought of it either until I read how the limiters work from the links.

I know that when I backwash my DE filter, there probably isn't time for the limiter to cool down between starts and stops of the pump, which I do at the timer (which controls everything).

Does shutting the SWG box off at the box help? In other words, is the limiter before or after the on/off switch (I'm guessing after, but not 100% sure).

Maybe this info should be added to Pool School for SWGs.