Auxiliary Electric Booster Element - Johnson a419

Auxiliary Electric Booster Element can be functional by adding a digital Aquastat controller.

Johnston Controls a419 Digital Aquastat
An Aquastat is a temperature setting device that uses a sensor to turn on and off an electric element, pump, or other device in a heating system.  In co...
Fri, Dec 23, 2016 at 7:14 PM