I have a Geostar (Waterfurnace) system using a Waterfurnace branded model TP32U03 thermostat. This thermostat is capable of using an outdoor temperature sensor to lock out auxiliary (in my case electric resistance) heating above a set temperature. However, the manual does not give a part number for this sensor. Does anyone know the part number or where I can order it? Alternatively, I assume this is an RTD sensor. I have found a Honeywell sensor, part number C7089U1006. Are the temperature/resistance coefficients fairly "standard" in these applications so that I could use this sensor with my thermostat?
Most thermistors are made by Western Digital. How many wires does the water furnace stat want to see? If two the Honeywell sensor will work. If the Stat wants three wires try the White Rodgers remote. Or call WaterFurnace,
This thermostat looks identical to ClimateMaster ATP32U03. (which I have) Here this a link to the spec for both the thermostat and outdoor thermometer ClimateMaster Inc. - Residential Thermostat Installation Manuals The spec is for a 'normal' J Curve, NTC 10K @ 25 C (2 wire) I went (really) cheap and just got a thermistor off of ebay. 2 pcs Thermistor in #6 Lug, 10K @ 25 C, J Curve, NTC I'm know these thermistors might not be as accurate but the one I hooked up is within 1 degrees of the mercury thermometer.
Using the right parts If the part; temperature probe in this case, meets the design specification, you can use anything from anywhere. I personally haven't got time or usually do not have that information, so I tend to stick with the recommended part by Honeywell, White Rogers or whatever. If the resistance range is incorrect, for example, than it would not read correctly, and that creates a new problem.