Johnson Digital Temperature Controller - Wired

Johnson Digital Temperature Controller - Wired

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The Johnson digital temperature controller is used to control the temperature of a refrigerator, or similar cooling or heating device. Enter your desired temperature, called set point, and how tightly you want your temperature maintained, called differential, and let the controller do the rest.

Ranco Vrs. Johnson 
This Johnson digital temperature controller is very similar to our popular Ranco brand controller (FE610) in application and appearance. The advantage of the Ranco is being able to switch between cooling and and heating from the digital interface, while with the Johnson you have to take the cover off and physically remove a jumper. The advantage of the Johnson is the very attractive price.

For technical aficionados the Johnson does have a feature called Anti-Short Cycle Delay. Cycling is the rapid turning off and on of an electrical device. Over time cycling can harm your appliance. The Johnson controller allows you to set a time interval, in minutes, that keeps the controller from turning on right after it shuts off no matter what the temperature reading is. This can be very useful when you are using a 1 degree of differential setting for tight control but want your compressor or power supply to have a minimum time period of rest before it turns back on. Temperature Range of -40 to 212F.

Item # FE609
Shipping Eligible for Free Shipping Program
Availability California - In Stock
Pennsylvania - In Stock
Weight 2 LBS
Community Q&A

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Browse 4 questions Browse 4 questions and 13 answers
Why did you choose this?
MoreFlavor Store
Charlie on Dec 23, 2022
I was told to buy this by my boss
Eric Peter W on Aug 5, 2021
Charlie on Dec 23, 2022
I was told to buy this
Eric Peter W on Aug 5, 2021
I was told to buy this by my boss
Eric Peter W on Aug 5, 2021
Keep proper temperature
Chris L on Jul 28, 2021
I want to turn a freezer into a ftidge
Keita H on Jul 6, 2021
Johnson reliability
Charles K on Jun 26, 2021
Johnson Control Reputation
Mark Jagodzinski on Apr 17, 2021
need it for keg storage
William J on Dec 28, 2020
Appears to be best in class for keg cooler temp control.
Duane on Sep 4, 2020
johnson has good rep. I need a single stage digital controller
jim s on Jun 8, 2020
It was recommended by a brewmaster in a local commercial brewery.
Todd W on Nov 23, 2019
need to control Ferm wrap
Dan A on Sep 14, 2019
Charlie B on Jun 11, 2019
Used in the past. Less condensation in keezer.
Edgar C on Jun 8, 2019
Making a freezer into a refrigerator
Matt Starr on Sep 13, 2018
Suggested by a fellow brewer
Shawn on Aug 23, 2018
Works. Have 2 already
Tim D on Apr 19, 2018
need to control my fermenting temp, and was recommended by a friend.
Mark H on Feb 14, 2018
To make a chest freezer into a fridge for a mobile cafe. This conversion is more space saving than a regular fridge.
Brenda de S on Jan 12, 2018
I was told to buy this
Eric Peter W on Aug 5, 2021
Keep proper temperature
Chris L on Jul 28, 2021
I read you no longer have to remove a jumper to change from heating to cooling. It can be done from digital interface. Is this true?
Kenneth Kahle on Jan 20, 2018
BEST ANSWER: Yes it’s true. But remember you can only monitor one or the other. In my case I have two units. One that’s controls heat and a separate unit that controls cold temperatures. I also thought that the instructions were a bit more technical and hard to follow unless you set up refrigeration systems for a living. It took me a couple of days to figure them out. My best tip and the one I missed at first (being a guy) is there is a picture of a flame or ice to help you know whether you are controlling hot or cold temperatures.
Hi! Is the probe submersible? I want to get into the middle of the tank. Cheers.
John on Oct 3, 2021
BEST ANSWER: IMO; no it is not submersible: To protect the sensor from moisture they recommend adding a dab of silicone at the junction of the sensor and the sensor wire. I doubt they would want you to fully submerge the sensor
What thermowell works with this controller?
Samuel Wells on Jun 24, 2021
BEST ANSWER: I use the BrewBuilt 1.5 inch Tri-Clamp thermowell. The probe is 4 inches and came with my BrewBuilt X1 Uni 7 gallon fermenter. I really like the Johnson A421 digital temperature controller. Well worth the money
What is the input voltage range for this device?
Freeman Wells on Aug 7, 2020
BEST ANSWER: Not sure if I can get to the specifics you want, but I use mine in a standard 110 volt/ 15 amp circuit in my
location that I use for fermenting.. Works like a charm.. Never have to babysit it like others I've used.
Hope that helps..

4.4 / 5.0
7 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Rated 5 out of 5
Worth the extra money over other controllers
I bought this controller to replace a controller whose sensor failed after a week. What I like about this controller

Temperature sensor can be replaced

You have the option to turn on or off the controller if the sensor fails. My other controller just kept my freezer running

Anti Short Cycle Delay. In addition, the controller displays how many minutes you have left on the delay.

Ease of programming

Accurate sensor reading

Very steady and well built.

I would highly recommend this controller
April 21, 2021
over 3 years ago
Rated 5 out of 5
Great value.
Tight temperature control. Easy to install without wading through a large instruction manual.
June 25, 2019
over 5 years ago
Rated 5 out of 5
Works great
I use one on a freezer for cold stabilization, and one on a fridge for cold fermentation. It is fairly easy to set up, keeps cool at a consistent temperature, and is well manufactured. Recommended!
July 16, 2018
over 6 years ago
Rated 1 out of 5
Missing part
Seems solid but it’s missing the jumper inside which prevents me from changing the settings. The settings are locked without the jumper. I will re-review after getting a 30 cent jumper from here or the manufacturer. Luckily I had a backup controller for my keeper!
June 13, 2018
over 6 years ago
Response from MoreFlavor
Hello James - Apologies A421 came without a jumper. These arrive in a factory sealed box and was unfortunately a manufacturing defect. If we can help with this stuation, please give us a call at 1-800-600-0033 or email info@moreflavor.com
June 13, 2018
Zach R Staff
Rated 5 out of 5
Affordable and works well!
Simple to use and set up, this works well with my new keezer!
Cool beer!
Cool beer!
April 3, 2018
over 6 years ago
Rated 5 out of 5
Great product
Great control easy to set up and use
March 10, 2018
over 6 years ago
Rated 5 out of 5
Works great.
Works great for fermentation temp control, keeps the temp within a degree or less of the setpoint using a thermowell on the fermenter and an older Kenmore fridge. Super easy to use and install.
January 20, 2018
over 6 years ago