How do I use a Polder thermometer with WSM?

[Guest]

I'm having problems with a Polder dual-sensor thermometer my wife gave me for Christmas.

I've had the same problem twice. When I take the thermometer out of the box it works fine. I stick the probe into the thigh of a chicken I'm cooking and run the cable out of the WSM. I put the lid gently down on top of the cable.

At first it works fine. Then later it starts showing high temperatures. I remove the probe from the chicken and cool it down and it still says it is 400 degrees - even though I'm holding it in my hand.

I returned the first one I got and now I've had the same problem with its replacement.

I emailed Polder and asked them if they have been having problems with this model and they said no.

I'm sure the store we got it at will take it back, et. al., but I'm just wondering if I'm doing something to wreck the thermometers.

I'm using a candy thermometer and I've used an oven thermometer and I know the temp inside the smoker is in the 250s so I can't be getting it that hot. Anyway, this Polder is supposed to work up to 500.

Thanks for any help.

- Bobby

 

[Jim Minion]

The dual probe units have been a problem and there a lot of failures. Your better off with two standard units.
Jim

 

[Preston Davenport]

Bobby,
The problems you are encountering sounds like when these units go bad due to connection problems. These probes are typically negative coeficient thermistors utilized as a Resistive Capacitive (RC) circuit (the resistive is the thermistor in this case). This RC circuit provides a bias to a frequency tuning circuit which provides a pulsed signal to a counter built into the chip in the digital thermometer. As the temperature varies the thermistor resistance varies causing the frequency to vary which the counter counts the cycles generated. As the temp goes up the resistance goes down and the bias on the RC circuit causes the frequency to increase. When the probe thermistors interconnection fails the frequency goes high thus creating the high temperature that is displayed.
The probe is broken, nothing more that you can do for it. If its a possible moisture problem, you might try the hot oil soaking method. If that doesn't work, you might try to substitute a Taylor probe but you will only be able to read one channel in that case.
PrestonD

 

[Bruce Bissonnette]

Preston,

I was actually getting physically excited reading your post /infopop/emoticons/icon_biggrin.gif , I don't have any idea what all that meant, but my guess is... he needs a new probe.

Just kidding buddy!!!

 

[Preston Davenport]

Hi Bruce,

I am going to try to put together a web page that will explain how these devices work in possibly easier terms..what I wrote above is not 100% accurate but explains in as simplest terms how this device works...but that web page is a work in progress.

Regards,
PrestonD