Single Stage Digital Temperature Control (120/240VAC SPDT)

A421 control used on outdoor wood burning unit . Easy to install and program , works as it should !

Replaced thermostat in refrigerator for more precise control. Works great.

The temperature control product is working fine. I had to replace an older version control box, and this replacement part was pretty easy to hook up.

The sensor wire is normally long enough to get out side the basement to pick up outside temperature without extending it, but can be up to 100ft! The back light is great. It automatically sets up to cooling or heating depending on the on and off setting configuration

Instant shipping..

i'm using two, in two maple sugar bushes for my vacuum pumps. they come on at 34, off at 31. works great. yes, i have recommend these to others.

Our solar heated radiant in-floor heating system is divided into two sections, one is the main house the other is the addition. In each section we use two A421s interconnected to control when the pumps come on and when they shut off. Johnson's tech support people were very patient and capable in helping me get the first two interconnected sensor relays set up. Couldn't have done it without them. The A421s have functioned without a single problem.

Always a pleasure!!

I bought it for my bar cooler. Replaced the existing mechanical thermostat.

I used this on a reach-in beverage cooler. It is small enough to fit in the space behind the top panel that would normally have pictures of the products being sold. The DIN rail mount made it very easy to secure. It only works for about 2 weeks a year for a fair, but worked flawlessly during those 2 weeks!