Penn A421 Series Installation Manual

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 you
can 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°F to 212°F
or -40°C 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 Guide
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)
Off-Cycle Defrost control
You can use the A421 Control with Off-Cycle Defrost to
set up regular, passive defrost periods of 1 minutes to 99
minutes. The defrost interval can range from 2 hours to 24
hours, or you can set it to 0 for no defrost interval. You can
also start or stop a defrost cycle in the following two ways:
Part No. 24-7664-3035 Rev. D
2018-11-13
A421ABD, A421AED