How to trick themal diode?

[Html33]

Hi

New to the forum and hope you guys with a little more electrical knowledge than my self can help me out.

I've got an Air Conditioning unit that is permanently running with a sensor that will kick the AC unit in and out (the main unit/fan is always running)

Now i intend to have the unit plugged into a remote thermostat which works great, only problem is once the power has been disconnected, and re-connected them temperature resets back to 25c, thus the unit not kicking in (until it's changed below the threshold) . 

The sensor hangs out the front, and if i squeeze it the temp raises and the units kicks in

Now my questions is;

How can i trick the unit? Can i cut the sensor off and cross the two connections across or will i need a transistor?

Thanks for the help!

 

[Richard-the-Ninth]

Why do you down power the remote thermostat?

What is the sensor that is in the picture connected to, and why cant you move that?

 

[Html33]

Why do you down power the remote thermostat?

What is the sensor that is in the picture connected to, and why cant you move that?

It's the way the temperature sensor/remote thermostat works, when the temperature has been reached the power is disconnected. When the temperature then goes back out of range it comes back on.(Problem is when the unit powers back up it's internal temperature is above the room temperature so it doesn't kick in, i want to trick the unit so it's always higher.....thus when power comes back on it engages

It's going to be deep within the unit, which i can't really be bothered to take apart considering the two wires that i would need to change are right there

 

[user 28595]

Put a small heater in front of the AC which runs for 60 seconds when the power comes on.

cheers, Paul

 

[Html33]

Put a small heater in front of the AC which runs for 60 seconds when the power comes on.

cheers, Paul

Cheers for the answer Paul

I can't do that! Just seems so counterproductive....

For now I have cut the sensor off as Richard-the-ninth suggested and extended it on a 3m cable, I for now have attached the probe to a 12V PSU which is always plugged in near by which produces enough heat to keep it above the threshold.

I cut the sensor off and shorted the two cables together and got error code E1, and when both disconnected get error E2.

So I'm guessing the measurement across the cables must either by Resistance or Voltage.

 

[phil d]

Cheers for the answer Paul

I can't do that! Just seems so counterproductive....

For now I have cut the sensor off as Richard-the-ninth suggested and extended it on a 3m cable, I for now have attached the probe to a 12V PSU which is always plugged in near by which produces enough heat to keep it above the threshold.

I cut the sensor off and shorted the two cables together and got error code E1, and when both disconnected get error E2.

So I'm guessing the measurement across the cables must either by Resistance or Voltage.

If you have a multimeter try disconnecting the device from the circuit and measure the resistance across it, apply gentle heat from a hairdryer and see if the resistance changes, it may then be possible to use a variable resistor in it's place to trick the unit into thinking it's warmer or cooler than it actually is.

My stepson bought a "chip" off Ebay to make his car faster, all it actually was was a resistor that connected to the temp sender, the engine thought it was colder than it was and so pumped more fuel into the cylinders. in effect it was like running with the choke partly on all the time, it made it a bit quicker, but the fuel consumption rose considerably.

 

[Html33]

If you have a multimeter try disconnecting the device from the circuit and measure the resistance across it, apply gentle heat from a hairdryer and see if the resistance changes, it may then be possible to use a variable resistor in it's place to trick the unit into thinking it's warmer or cooler than it actually is.

My stepson bought a "chip" off Ebay to make his car faster, all it actually was was a resistor that connected to the temp sender, the engine thought it was colder than it was and so pumped more fuel into the cylinders. in effect it was like running with the choke partly on all the time, it made it a bit quicker, but the fuel consumption rose considerably.

Sounds like a good idea. I have a mulit-meter digging around somewhere, never measured resistance but can't be hard!

 

[user 28595]

My stepson bought a "chip" off Ebay to make his car faster, all it actually was was a resistor that connected to the temp sender, the engine thought it was colder than it was and so pumped more fuel into the cylinders. in effect it was like running with the choke partly on all the time, it made it a bit quicker, but the fuel consumption rose considerably.

Those pesky car manufacturers have no idea how to make an internal combustion engine.

cheers, Paul

 

[phil d]

Those pesky car manufacturers have no idea how to make an internal combustion engine.

cheers, Paul

Oh dear Paul, not another one that hankers back to those halcyon days of Webber and SU carburettors, manual chokes and when maintaining your own motor only required about half a dozen spanners, rather than the modern car where you need a computer and about a grands worth of special tools just to empty the ashtray. lol. I thought there was only me left, nice to know I'm not on my own out here.

Incidentally if anyone has got a Morris Marina or an Austin Maxi they don't want feel free to throw it my way.   

 

[user 28595]

I like tinkering with cars, but I really like fuel injection and modern electronics - get in, turn the key, go (don't even turn the key these days, it stays in my pocket).

cheers, Paul

 

[phil d]

I like tinkering with cars, but I really like fuel injection and modern electronics - get in, turn the key, go (don't even turn the key these days, it stays in my pocket).

cheers, Paul

Blimey, that must get expensive, I mean, breaking a window and barrelling the ignition every time you want to go anywhere! :slap