A421 Digital Electronic Temperature Controller (Replaces A419 model)

(2 reviews) Write a Review
A421 Digital Electronic Temperature Controller | BREW International

The A421 Digital Electronic Temperature Controller replaces the discontinued A419 model, it is a single stage, electronic temperature controller with a single-pole, double-throw (SPDT) output relay, designed for homebrewers of beer and wine. It features an adjustable backlit LCD for viewing the temperature and status of other functions and a three-button touchpad for setup and adjustment. An LED indicates the On/Off status of the output relay.

The A421 control is 120 VAC. The A421 controls provide heating or cooling control, sensor offset, temperature setback, adjustable anti-short cycle delay and a restricted user adjustment mode. The temperature units can be displayed in °F or °C. The temperature adjustment range is -40 to 212°F or -40 to 100°C. The A421 automatically changes from heating and cooling. 

The A421 controls are available in Type 1/IP20 high-impact plastic enclosures suitable for surface or DIN rail mounting and Type 4X/IP66 watertight, corrosion-resistant surface mount enclosures.


Have more control over your homebrewing batches of beer, wine or cider. Buy now from BREW International. Ships fast, competitive pricing. 

2 Reviews Hide Reviews Show Reviews

  • 5
    Great Product, Amazing Service

    Posted by nicholas.impellitteri@theyeastbay.com on 13th Nov 2019

    I needed another controller for a new fermentation chamber I was bringing online, and this works great for the job. The first one sent was defective and would not kill the power correctly, and Brew International got a new one out to me very quickly. Amazing service for sure!

  • 5
    A421 Digital Electronic Temperature Controller

    Posted by David on 4th Dec 2017

    Simple to setup and use, especially if you are only controlling the temperature of a fridge or freezer for a kegerator/keezer! Also, the price is as good as you will find for this quality unit. Delivery was quick too!