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SWINGRRRR
05/25/2008, 07:37 AM
All I have right now is a CD4HD to run the lights and temp. I will be getting a DC8 soon. My tank has 4X96watt T5's. I can control 2 at a time.
LT1$-A1 - Actinic 2X96 Watt T5s
LT2$-A2 - Whites " "
FLT$-A3 - Fuge/ Melevs Bulb
HET#-A4 - Heater Won 250Watt Ti.

If Sun 000/000 Then LT1 ON
if Temp > 83.0 Then LT2 OFF
Max Change 010 M Then LT1 OFF
If Sun 060/-045 Then LT2 ON
if Timer LT1 = OFF Then FLT ON
if Timer LT1 = ON Then FLT OFF
If Temp < 79 Then HET ON
if Temp > 81 Then HET OFF

kenargo
05/25/2008, 09:59 AM
Looks like it will work. You may want to add a line like this:

If Temp < 70 Then HET Off

This will catch a temp probe failure.

SWINGRRRR
05/25/2008, 10:34 AM
I understand that, that means that if the temp gets below 70 the heater will turn off, but how does that catch the temp probe failure?

kenargo
05/25/2008, 10:39 AM
When temp probes fail one of 2 things happen; either they read very high (100 F or more) or they read low (40 F or lower). If your probe where to fail low with the existing program the heaters would stay on forever, possible increasing the tank temp.

There is another option, leave the program as is but adjust the heaters so they are only slightly higher temp setting than the AC3; they you wouldn't have no heat but you would still be protected.

SWINGRRRR
05/25/2008, 11:13 AM
I didn't realize that would program into it. I planned on bumping the heater up a degree or so. If things failed it still wouldn't heat uncontrollably.

Thank you for your input. Hopefully ill have it on by the end of the day.