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maroun.c
05/27/2009, 08:01 AM
-Is there a temperature probe for ambient temp (not underwater) that can be attached to the AC to start a fan when canopy temp reaches certain temp for example?

when you usually run a controller on a chiller and the AC shutts off the chiller for some time like at night when temp is cool could that lead to draining the batter of the chiller memory?

-could you set two commands chiller line like:
-Turn on chiller for 30 min every hour at halide ON time (just
to charge the chiller memory if needed or at least to allow the
chiller temp control to take charge if the controller temp probe
fails?)
-Then turn ON/OFF chiller at 81/79?

-In above scenario how does the chiller handle to conflicting commands like if it's set to turn ON from 2:00 to 2:30 and at that time the temp is 79?

kenargo
05/27/2009, 09:34 AM
-Is there a temperature probe for ambient temp (not underwater) that can be attached to the AC to start a fan when canopy temp reaches certain temp for example?

I use the same probe for both and have never had any issues.

when you usually run a controller on a chiller and the AC shutts off the chiller for some time like at night when temp is cool could that lead to draining the batter of the chiller memory?

I've never heard of this practice; temp should be based on water temp and not air temp. I've also never seen a chiller that used a battery to hold programming and if they did it would likely be a lithium battery and not charged.

The program is possible and will work but you appear to placing a lot of attention to the chiller battery rather than the tank health.

phuzzykins
05/27/2009, 10:16 AM
I planned to just use an old thermostat (I have a few kicking around from when I upgraded to programmable ones) connected to a digital input on my AquaController. You could even use a bimetallic reed switch (used in some thermostats with fixed temperature settings) if you wanted to keep it simple.

It seems like a lot of expense to get a probe expansion module just to get an extra temperature probe, if all you really care about is turning on a fan.

kenargo
05/27/2009, 04:45 PM
<a href=showthread.php?s=&postid=15084710#post15084710 target=_blank>Originally posted</a> by phuzzykins
I planned to just use an old thermostat (I have a few kicking around from when I upgraded to programmable ones) connected to a digital input on my AquaController. You could even use a bimetallic reed switch (used in some thermostats with fixed temperature settings) if you wanted to keep it simple.

It seems like a lot of expense to get a probe expansion module just to get an extra temperature probe, if all you really care about is turning on a fan.

I had originally though the same but ended up going with a connected probe so that i could read/report the temperature and make decisions based on same. Using a simple thermostat will give you contact closure that can be reported via a switch input but I wanted more (isn't that always the problem though;)

phuzzykins
05/27/2009, 05:45 PM
Spoken like a true engineer, Ken. :)

maroun.c
05/27/2009, 11:08 PM
<a href=showthread.php?s=&postid=15084496#post15084496 target=_blank>Originally posted</a> by kenargo
I use the same probe for both and have never had any issues.



I've never heard of this practice; temp should be based on water temp and not air temp. I've also never seen a chiller that used a battery to hold programming and if they did it would likely be a lithium battery and not charged.

The program is possible and will work but you appear to placing a lot of attention to the chiller battery rather than the tank health.

Thanks for yuor reply. Chiller will be controlled by tank temp however I would ike to startup some fans when the canopy temp reaches a certain level or for my stand which will house the chiller.
Chiller memory andor battery if it exists will in the end reflect on tank health as if for some reason the chiler loses its set temp that could affect the tank badly or is this stored in non volatile memory usually?

phuzzykins
05/28/2009, 07:58 AM
You'd have to check with the chiller manufacturer to be sure, but I'd expect that on a digitally controlled chiller, the set point would be stored in non-vol memory.

Most microcontrollers have enough non-vol memory on board for this - it would just add cost to add battery-backed RAM for the purpose.

As Ken said, even if using battery-backed RAM, it's unlikely that it would be backed by anything other than a non-recharging button cell battery.

In short: my opinion is that you're giving this issue far more attention than it deserves. :)

RussM
05/28/2009, 09:41 AM
maroun.c, my 2 cents...

Regarding the chiller: I believe in handling chiller and heaters the same way - let the built-in thermostat/temp control function in those devices do what they are designed to do, and use the AC as a safety measure in event of a problem with the heater or chiller. For example, if your chiller was set at 78F+/-1°, you'd program the AC to leave the chiller powered up at all times unless the temperature got too low, perhaps 75.5°. Same for a heater... let the heater control the temp normally, and have the AC shut down the heater if the heater 'goes runaway'.

As for the canopy fans, why not just tie the control of the fans to the operation of your canopy lighting? If the lights are on, then the fans are on. Simple & effective. This works great for me. My canopy fans are thermistor-controlled... when the lights come on, they start out turning at moderate speed; as the temp increases, they go faster. It took a bit of tweaking to get the right combination of air movement vs fan noise, but I found a happy medium and am pleased with the outcome.

phuzzykins
05/28/2009, 10:24 AM
Good points Russ... as long as you aren't using the seasonal temperature feature in the AC, of course.

I'm still in the middle of my 300 gallon build, so not much is hooked up yet. My plan is to let the Apex control my heaters, and let the chiller use its own thermostat. I just don't trust the accuracy of the thermostats on the heaters.

Which fan controller do you use?

RussM
05/28/2009, 11:15 AM
<a href=showthread.php?s=&postid=15091373#post15091373 target=_blank>Originally posted</a> by phuzzykins

Which fan controller do you use? variable-speed ThermalTake 12v PC fans. I just had to change the stock trimpot to get the speed range I needed when using the thermistors. Otherwise:
If Time > 00:00 Then FAN OFF
If Timer T5A = ON Then FAN ON //IC660 #1
If Timer T5B = ON Then FAN ON //IC660 #2
If Temp > 80.0 Then FAN ON

maroun.c
05/29/2009, 07:28 AM
Russ,
funny why was I thinking the opposite. Totally makes sense.
I am giving it a lot of thought cause I'm frequently on travel for 1-2 weeks and any risk of anything going wrong is not acceptable in my case...
Guess I'll do the same for my heaters and Chiller.
For fans I would also have them run even without lighting to get humidity out of the canopy and stand (and room) I've had hinges rust in weeks If fans were not running on and off all day long...

Thanks

RussM
05/29/2009, 08:57 AM
<a href=showthread.php?s=&postid=15096758#post15096758 target=_blank>Originally posted</a> by maroun.c
Russ,
funny why was I thinking the opposite. Totally makes sense.
I am giving it a lot of thought cause I'm frequently on travel for 1-2 weeks and any risk of anything going wrong is not acceptable in my case...
Guess I'll do the same for my heaters and Chiller.
For fans I would also have them run even without lighting to get humidity out of the canopy and stand (and room) I've had hinges rust in weeks If fans were not running on and off all day long...

Thanks

You could just expand on the approach I use, and have the fans cycle on and off periodically during those times the lights are not on...

If Time > 00:00 Then LIT OFF
If Time > 00:00 Then FAN OFF
If Time > 10:00 Then LIT ON
If Time > 16:00 Then LIT OFF
OSC 005/025 ON/OFF Then FAN OFF
If Timer LIT = ON Then FAN ON
If Temp > 80.0 Then FAN ON

The OSC statement *must* be before the Time LIT & If Temp statements for this to work properly.

This would run the fans if the lights are on, if the tank temp is high, and for 5 minutes every half hour even when one of the other FAN ON conditions is not met. Food for though, at least.