Thomas - 4239 Traceable Hi-Accuracy Refrigerator Thermometer, with 2 Bottle Probe, -58 to 158 degree F
Key features
- •High-accuracy refrigerator thermometer has -58 to +158 degrees F/-50 to +70 degrees C temperature range with +/- 0.3 degrees C accuracy for use in refrigerators, water baths, heat blocks, and incubators
- •Choice of temperature-buffered bottle sensor or waterproof probe sensor, and 10-foot long micro cable allows doors to be closed on it
- •Three-line LCD simultaneously displays minimum, maximum, and current temperature, and alarm provides visual and audible alarms for out-of-range temperatures
- •Meets CDC requirements for thermometers and vaccine thermometers, and includes NIST Traceable Certificate provided by an A2LA-accredited ISO 17025 calibration laboratory to ensure accuracy and traceability
- •Hi-Accuracy thermometer
- •Probe(s)
- •(2) AA batteries
- •NIST Traceable Certificate
Thomas - 4239 Traceable Hi-Accuracy Refrigerator Thermometer, with 2 Bottle Probe, -58 to 158 degree F
List Price: $190.94$171.85DEALYou Save: $19.09 (10%)
Free shippingFree Returns – 30 daysFree Order CancellationSecure Payment2–3 Days DeliveryGet It June 23, 2026In Stock (3)No marketing spamNo account requiredFulfilment by FedEx / Amazon / UPS / ShipwirePayPal / Card Buyer Protection
Customer Reviews
Reviews sourced from verified Amazon purchasers4.0
out of 5
Based on 10 reviews
5★
80%
4★
20%
3★
0%
2★
0%
1★
0%
No off switch,but very accurate
Adam V. Floyd✓ Verified Purchase•August 3, 2023
Very accurate unit. I use it to calibrate my other thermometers. One criticism is that it doesn't have an off button to prolong battery life.
Great product!
Mugwump✓ Verified Purchase•July 11, 2023
I recently bought a new fridge - and I'm using this thermometer to test out the various areas of the fridge (freezer, meat chiller, fruit & veg compartment etc). Bought this one for its accuracy and calibration - and couldn't be happier with my purchase
Works great
Matt✓ Verified Purchase•June 18, 2023
Update 11-18-2015:
Reporting in to say this device is still working fine and I'd continue to recommend it :) Aside from occasional strange behavior brought about by failing batteries, I've never had any trouble with it and am recommending one to my parents.
Update 11-29-2013:
Just wanted to write back that after a year, it still works well. On Thanksgiving, it saved a bunch of produce in our fridge from getting frozen. I've had the alarm set at 31.5 and it went off. Our new refrigerator (with a built-in temperature sensor) claimed the interior was 39 but I don't believe it and still use the Thomas thermometer instead.
The batteries in the original unit proved flaky. The thermometer reset itself several times inexplicably. After replacing the generic batteries with decent ones, it's been very reliable.
Update 1-22-2013 - READ THIS:
Several comments noted a misrepresentation in Amazon's description. Note that this review applies to "Thomas Traceable Hi-Accuracy Refrigerator Thermometer, with 2 Bottle Probe." Amazon lists this review under several distinct products, and some DO NOT include the bottle probes. Be sure to order the right item. For example, manufacturer part number 4240 does not include the bottles, and 4238 includes only one bottle. This review applies to manufacturer part #4239 which DOES include the two bottles. To add to the confusion, the thomassci.com website lists the part number as 1227U04. If you want two bottles, be sure you're getting part 1227U04 or 4239.
Original review:
- The thermometer includes a certificate proving it's calibrated. They use 3 temperatures for calibration: -40C, 0C, and 50C.
- I'm using it with a Hotpoint refrigerator in a cheap apartment. Why would anyone buy this thermometer for use on a fridge that likely cost less than the thermometer? Because I'll be moving out of this place soon and plan to get a refrigerator that actually works then. The results I've seen provide empirical evidence that Hotpoint refrigerators -- mine anyway -- are junk: the temperature fluctuates from ~32.5F to ~40F. I've done everything I can think of to moderate it but have failed.
- This thermometer makes it clear when the freezer is running the auto-defrost cycle. Temperatures rise for -5F to +10F before cooling off again. My manual-defrost chest freezer does not exhibit this behavior, as expected.
- The wires are thin but still do let a small amount of cold air out. Wireless would be better but more expensive / prone to interference. More batteries then too.
- The bottle probes seem to be made of glass. They seem pretty durable.
- Having a thermometer that does not require opening the fridge to see the temperature is a big plus.
- Thomas does offer a recalibration service if you need it.
- I like the alarm feature, which alerts you if the temperature goes outside a designated range. Both probes can have independent associated alarms, so you can monitor both the freezer and fridge independently.
- The wires attached to the probes are very long. I can't imagine they would be too short for any reasonable application. You could easily monitor two adjacent large refrigerators/freezers if you needed to.
Bottom line:
Unless you need +/- 0.01F precision, you would likely be fine with a different calibrated thermometer. I just bought it because I appreciate a high-quality instrument, and so I can prove to the landlord that my fridge is no good.
Reporting in to say this device is still working fine and I'd continue to recommend it :) Aside from occasional strange behavior brought about by failing batteries, I've never had any trouble with it and am recommending one to my parents.
Update 11-29-2013:
Just wanted to write back that after a year, it still works well. On Thanksgiving, it saved a bunch of produce in our fridge from getting frozen. I've had the alarm set at 31.5 and it went off. Our new refrigerator (with a built-in temperature sensor) claimed the interior was 39 but I don't believe it and still use the Thomas thermometer instead.
The batteries in the original unit proved flaky. The thermometer reset itself several times inexplicably. After replacing the generic batteries with decent ones, it's been very reliable.
Update 1-22-2013 - READ THIS:
Several comments noted a misrepresentation in Amazon's description. Note that this review applies to "Thomas Traceable Hi-Accuracy Refrigerator Thermometer, with 2 Bottle Probe." Amazon lists this review under several distinct products, and some DO NOT include the bottle probes. Be sure to order the right item. For example, manufacturer part number 4240 does not include the bottles, and 4238 includes only one bottle. This review applies to manufacturer part #4239 which DOES include the two bottles. To add to the confusion, the thomassci.com website lists the part number as 1227U04. If you want two bottles, be sure you're getting part 1227U04 or 4239.
Original review:
- The thermometer includes a certificate proving it's calibrated. They use 3 temperatures for calibration: -40C, 0C, and 50C.
- I'm using it with a Hotpoint refrigerator in a cheap apartment. Why would anyone buy this thermometer for use on a fridge that likely cost less than the thermometer? Because I'll be moving out of this place soon and plan to get a refrigerator that actually works then. The results I've seen provide empirical evidence that Hotpoint refrigerators -- mine anyway -- are junk: the temperature fluctuates from ~32.5F to ~40F. I've done everything I can think of to moderate it but have failed.
- This thermometer makes it clear when the freezer is running the auto-defrost cycle. Temperatures rise for -5F to +10F before cooling off again. My manual-defrost chest freezer does not exhibit this behavior, as expected.
- The wires are thin but still do let a small amount of cold air out. Wireless would be better but more expensive / prone to interference. More batteries then too.
- The bottle probes seem to be made of glass. They seem pretty durable.
- Having a thermometer that does not require opening the fridge to see the temperature is a big plus.
- Thomas does offer a recalibration service if you need it.
- I like the alarm feature, which alerts you if the temperature goes outside a designated range. Both probes can have independent associated alarms, so you can monitor both the freezer and fridge independently.
- The wires attached to the probes are very long. I can't imagine they would be too short for any reasonable application. You could easily monitor two adjacent large refrigerators/freezers if you needed to.
Bottom line:
Unless you need +/- 0.01F precision, you would likely be fine with a different calibrated thermometer. I just bought it because I appreciate a high-quality instrument, and so I can prove to the landlord that my fridge is no good.
high quality, high precision
JRF MD✓ Verified Purchase•June 2, 2023
impressive accuracy, only had it for a while but exactly what I need (monitoring drug refrigerator
Great for refrigerator calibration
D. Coral✓ Verified Purchase•May 24, 2023
I'm using this with the 2 bottle probe to calibrate the temperature controller offset for my Perlick undercounter fridge. Originally I was thinking that 1 bottle probe might be enough, but I'm glad I bought the 2 bottle version instead. There is a 2 to 4 degree temperature difference between the very top and bottom shelves, even though the fridge has a circulation fan. I was able to set the differential perfectly so the drink cans on the colder shelf don't explode, while keeping the warmer shelf slightly above freezing.
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