Install Instructions

ManualsBrandsJohnson Controls ManualsA421 Series Temperature ControlsSingle Stage Digital Temperature Control (120/240VAC SPDT)

A421 Series Standard Electronic Temperature Controls Installation Instructions

A421 Control Parameter Setup Menus

The A421 temperature controls provide a Basic and an

Advanced setup menu that allow you to scroll through

the parameter setup codes, view and edit parameter

values, and set up your control for your application

requirement. The control also has a Restricted

(adjustment) menu. See Restricting User Adjustment

for more information.

Note: The A421 control retains a copy of the saved

parameter values in memory. When you change and

save a new value, the new value immediately

overwrites the previous value and is saved to memory.

In the event of a power failure, brown out, or when you

disconnect power from the control, all of the current

parameter values in memory are retained.

Reconnecting power to the control restores all of the

saved values.

Menu Navigation Guidelines

The A421 control buttons and display operate the

same in Basic and Advanced menu options. While in

any parameter code screen, the following behavior is

observed:

• The parameter code flashes on and off.

• Press  or  to navigate through all of the

parameter code screens.

• To exit either menu and return to the Main screen,

press  and  simultaneously.

While in any parameter code screen, the following

behavior is observed:

• The parameter value flashes on and off.

• Press  or  to scroll through all of the available

parameter values for the associated parameter

code.

• With the preferred parameter value displayed,

press MENU to save the value and go to the next

parameter code screen.

Note: If you do not press MENU to save a new value,

the control reverts to the last saved value.

After 30 seconds of inactivity, while in any screen, the

control reverts to the Main screen.

Basic Menu

The Basic menu allows you to quickly edit the On and

OFF temperature values, as well as the Sensor Failure

Mode (SF) and Anti-Short Cycle Delay (ASd) value.

See Parameter Codes and Modes of Operation

and

Table 4 for more information regarding parameter

codes, usable parameter values, and default values.

Viewing and Changing Values in the Basic Menu

To access the Basic menu and view and change the

Basic parameter values, follow these steps:

1. With the Main screen displayed,

press MENU. The LCD displays OFF,

which is the first parameter code

screen displayed in the Basic menu.

2. Press  or  to scroll through all of

the Basic parameter codes and

display the preferred code.

3. With the preferred parameter code

displayed, press MENU to display the

current parameter value for the code.

4. With the current parameter value

displayed, press  or  to scroll

through all of the parameter’s usable

values and display the preferred

value.

5. With the preferred parameter value

displayed, press MENU to save the

displayed value and go to the next

parameter code.

Figure 7: Navigating the Basic Menu

OFF