A421 Series Electronic Temperature Controls with
Off-Cycle Defrost
Installation Instructions
A421ABD-x, A421AED-x
Applications
IMPORTANT: Use this A421 Series Electronic
Temperature Control only as an operating control.
Where failure or malfunction of the A421 control could
lead to personal injury or property damage to the
controlled equipment or other property, additional
precautions must be designed into the control
system. Incorporate and maintain other devices, such
as supervisory or alarm systems or safety or limit
controls, intended to warn of or protect against failure
or malfunction of the A421 control.
IMPORTANT: Utiliser ce A421 Series Electronic
Temperature Control uniquement en tant que
dispositif de régulation. Lorsqu'une défaillance ou un
dysfonctionnement du A421 control risque de
provoquer des blessures ou d'endommager
l'équipement contrôlé ou un autre équipement, la
conception du système de contrôle doit intégrer des
dispositifs de protection supplémentaires. Veiller
dans ce cas à intégrer de façon permanente
d'autres dispositifs, tels que des systèmes de
supervision ou d'alarme, ou des dispositifs de
sécurité ou de limitation, ayant une fonction
d'avertissement ou de protection en cas de
défaillance ou de dysfonctionnement du
A421 control.
The A421 Series Electronic Temperature Controls are
single-stage, electronic temperature controls with a
single-pole, double-throw (SPDT) output relay.
A421 controls feature a backlit LCD with adjustable
brightness and three-button touchpad interface that
can be set up to restrict user adjustments. An LED
indicates the output relay's On/Off status.
A421 controls have simple On and Off temperature
settings for heating or cooling, an adjustable anti-short
cycle delay, temperature setback, and sensor offset
capability. The temperature control range is
40 to 212°F or -40 to 100°C.
The A421 controls are available either in Type 1
(NEMA), IP20 (CE), high-impact plastic enclosures
suitable for surface or DIN rail mounting (Figure 1)
or in Type 4X (NEMA), IP66 (CE) watertight, corrosion
resistant surface mount enclosures (Figure 2).
A421 Series Electronic Temperature Controls with Off-Cycle Defrost Installation Instructions
Refer to the
QuickLIT website
Dimensions
Figure 1: A421 Control with Type 1 (NEMA),
IP20 Enclosure Dimensions, in. (mm)
Figure 2: A421 Control with Type 4X (NEMA),
IP66 Enclosure Dimensions, in. (mm)
1
Part No. 24-7664-3035, Rev. A
Issued November 25, 2015
for the most up-to-date version of this document.
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