Johnson Controls A421AED-01C — Line-Voltage Electronic Temperature Control with Off-Cycle Defrost Timer, Type 4X/IP66, 120/240 VAC, A99BB-25C Sensor

Single-stage electronic temperature control with SPDT relay output and integrated off-cycle defrost timer, in a watertight Type 4X / IP66 high-impact thermoplastic enclosure for surface mount. Backlit LCD with 3-button touchpad. Defrost (per LIT-1900935): passive defrost periods 1 to 99 minutes; defrost interval 2 to 24 hours (or 0 = disabled); manual defrost start/stop. Supply: 120/240 VAC, 50/60 Hz (Class 2: 108/110/115/120 or 208/230/240 VAC). Included sensor: A99BB-25C PTC, 2 in. (5.1 cm) probe, 9-7/8 in. (0.25 m) PVC cable. Setpoint range: -40 to 212°F (-40 to 100°C). Sensor offset adjustable ±5°F / ±3°C. Adjustable anti-short-cycle delay, switch-activated temperature setback (binary input), sensor-failure relay mode, restricted adjustment mode. Operating ambient: -40 to 140°F (-40 to 60°C), 0–95% RH non-condensing (Type 4X). Sensor type: A99 Series PTC, 1,035 Ω at 77°F (25°C). Power consumption: 1.8 VA maximum. Listings: cULus (UL 60730, File E27734 Vol. 1), FCC Part 15 Class B, ICES-003, CE Mark, RCM. Installation note (per datasheet): cover screws must be torqued to 10–12 in·lb (1.1–1.4 N·m) to maintain the Type 4X / IP66 rating. Note: Relay output current ratings are not published in the LIT-1900935 product bulletin — confirm load compatibility against the installation guide before specifying. Source: Johnson Controls LIT-1900935 product bulletin.