Replace tekmar sensor with generic thermistor?

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foxt

Member
Jun 16, 2008
69
Hudson Valley, NY
It appears that the outdoor sensor for my tekmar zone controller has failed. Can I replace that with a generic 10k @25C thermistor with the same beta, or is there something special about the tekmar sensor that warrants the $20-$30 premium?

Tom
 
foxt said:
It appears that the outdoor sensor for my tekmar zone controller has failed. Can I replace that with a generic 10k @25C thermistor with the same beta, or is there something special about the tekmar sensor that warrants the $20-$30 premium?

Tom

The R-T characteristics of most thermistors are accurately described by the Steinhart-Hart equation:

1/T = A + B*(Ln R) + C*(Ln R)3

Since A, B, and C are constants, once you know the resistance at one temperature, the relationship of resistance to temperature is the same for any other thermistor that has the same reference point. So yes, is 10K thermistor, is generic, all same, and I can't see how there could be anything special about the Tekmar part, assuming they're using metric ohms.

I can't speak for Tekmar, but I do know from having worked on the other side of these sorts of pricing decisions that it could be their way of saying hey, we're willing to support the logistics to supply this third-party component, but maybe if we price it high enough the customer will be motivated to go find one elsewhere and let us concentrate on supporting our value-added products.

--ewd
 
Don L said:
ewdudley said:
assuming they're using metric ohms.

--ewd

Just curious, what's a "metric ohm"? Never heard that term before.
Just a lame attempt at ironic humor. Ohms is the only term in the equation that isn't subject to confusion caused by the SI/English/Metric/Rankine/Kelvin/Celsius/Fahrenheit mess.

Cheers --ewd
 
ewdudley said:
Don L said:
ewdudley said:
assuming they're using metric ohms.

--ewd

Just curious, what's a "metric ohm"? Never heard that term before.
Just a lame attempt at ironic humor. Ohms is the only term in the equation that isn't subject to confusion caused by the SI/English/Metric/Rankine/Kelvin/Celsius/Fahrenheit mess.

Cheers --ewd


Thanks! That's what I thought. Something like a pipe stretcher, eh?
 
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