HVAC – Installing An A421 Digital Control In A Walk In Cooler

In this HVAC video, I replace an older A19 mechanical thermostat with an upgraded A421 digital control. The A421 includes many functions which include, Anti Short Delay, Sensor Offset for Calibration, Separate On/Off set points and more. On completion, I use the Testo 440 with 323 Air Quality Probe to verify. See some links below, Happy HVACing!

Save 8% on your purchase at https://www.trutechtools.com using promo code “knowitall” at check out. See link below for preferred Testo pricing.

Visit https://www.hvacknowitall.com for articles, tips, and tool reviews.

Listen to The HVAC Know It All Podcast
Check out my podcast, HVAC Know It All Podcast, on Anchor: https://anchor.fm/hvacknowitall

Testo 440

A421 Controller