View Full Version : Breaking the code on Andover stats...
08-03-2004, 09:29 PM
Got an ELB store that wants to change the temp settings, any ideas?
08-04-2004, 06:02 PM
Andover's 256 and Infinity systems are programable. The Room Temperature Sensor has a 10,000 ohm at 77 deg thermister to sense room temperature input and a 10,000 ohm sliding potentiometer to sense a user adjustment input.
The program usually (dependent upon the individual programmer) has a base setpoint of 72 deg. The code usually states something like "Room temperature setpoint = base setpoint + slider adjustment). Thus if the base = 72 and the slider adjust is set up in the programming so that 10,000 ohm = an adjustment of plus 3 deg then the RoomTempSetPt will be 75 deg--- 72(base) +3(slider adjust).
This is if the user has set the slider all the way to the plus side of the potentiometer. If the slider is adjusted all the way to the minus side (240 ohms, -3) then the RoomTempStPt would be 69 deg--- 72(base) -3(slider adjust).
The program could quite simply state something like
"RoomTempStPt = 74".
If you have access to the programming just change these parameters. If you DONT then here are some of my "Rube Goldberg" ideas:
1a: Add a resistor to the room thermister, either in series or parallel to raise or lower the sensed room temp by 130 ohm per degree desired (10,000/77). This might fool the controller into thinking that the room is hotter or colder than it really is adjust the heat/cool to this "false load".
1b: Maybe use a Honeywell adjustable potentiometer with a warmer/cooler faceplate.
2: A variation of #1, add a floating thermostat and relay to short or open the thermister to drive the contoller full heat or full cool.
3: Too hot, install toaster near sensor and make toast. Too cold, hang bag of ice off sensor! (I actually saw this in a physics lab)!!
Finally, these ideas come with a disclaimer. You risk shorting out an input on the controller which could require an Andover tech to repair/reprogram it.
Lets here some more ideas!
[Edited by powerhead on 08-04-2004 at 06:09 PM]
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