programming question

[camelo]

hi
i have a question about the following statement:

if temp > 81 then fan on
if temp < 79 then fan off

this means that the fan will turn on at 81 degrees but does it stay on until it drops below 79 or 81?

thanks for the help

carlos

[Member No. 1]

Carlos, The fan would turn off when the temp hit 79*
HTH

[clp]

The fan will turn on when the temperature go to or above 81.1. It will then remain on until the temperature drops to 78.9 or below.

Curt

[camelo]

ok thats what i thought

just wanted to make sure before i fine tune the heater and the fan

thanks for the help
and a great product

[reefmaint]

DUMB... hate to say but why the heck would u want it to heat cool heat cool heat cool heat cool.

makeit if temp >81 on
if tem < 81 off

[clp]

Why the attitude? There is no controlled heating going on in his statements; just a gradual rise in temp from lights, pumps, etc. The problem with your statements is the deadband is too narrow and will result in frequent on/off cycle of the fan, chiller, etc. If the temperature is oscillating between 80.9 and 81.1 the fan could be cycling on/off every few seconds/minutes. A good way to wear out a fan/chiller in short order.

Curt

[reefmaint]

yeah i mean fan on fan off. slow rise of temp then slow cool then slow rise. isnt very good for coral. if u have the option to do it. keep the tamp the same and maby not the small area i said but 79 - 81 is 2 degrees. to much imo.
i think better thing to do would bne leave fans on all the time. then HEAT the tank to the propper temp
with most ppl who have temp going up and use fans to cool. it isnt gonna cycle cause it will struggle to bring that temp down. and usualy your lucky to just slow the rise of the temp duting the day

[liquidfunk]

I just have my fans turn on with the lights,,,, nothing then is cycling, but I let the chiller do the work for controlling water temp,,,, fans just make the chiller run less.

[RustySnail]

Originally posted by reefmaint
79 - 81 is 2 degrees. to much imo

My temp swing is 77-82 deg over 24 hours with no problems. SPS are growing like weeds.

[Reefer Maddness]

Originally posted by clp
Why the attitude? There is no controlled heating going on in his statements; just a gradual rise in temp from lights, pumps, etc. The problem with your statements is the deadband is too narrow and will result in frequent on/off cycle of the fan, chiller, etc. If the temperature is oscillating between 80.9 and 81.1 the fan could be cycling on/off every few seconds/minutes. A good way to wear out a fan/chiller in short order.

Curt

That and its a good way to drive your wife nuts...