Intermatic GMXST-I-120 Timer

The Intermatic GMXST-I-120 is a heavy-duty 24-hour electromechanical timer engineered for light-duty commercial and industrial HVACR applications. Operating at 120V AC, this SPDT switch supports a robust 21-amp resistive load and is rated for up to 1 HP at 120 VAC. As a veteran-grade mechanical time switch, it features captive trippers with 15-minute minimum switching intervals, allowing for precise cycling of pumps, motors, fans, and refrigeration merchandisers. The unit is housed in a UL Type 1 indoor plastic enclosure (NEMA 1), though it is also compatible with Type 3R outdoor enclosures if swapped. Designed with finger-safe terminals and a true clock face, it ensures high visibility and simplified field programming. The manual 3-way override (ON/OFF/AUTO) provides immediate local control, making it an essential component for aeration, septic treatment, and lighting control circuits where reliability is non-negotiable.

• High Load Capacity: Rated for 21A resistive and 1 HP, making it suitable for motors and general electrical circuits.
• Precision Control: Features 15-minute intervals for flexible 24-hour scheduling.
• Simplified Service: Equipped with a manual 3-way override switch for quick system testing without disrupting pre-set schedules.
• Enhanced Safety: Includes finger-safe terminals and screw terminal connections that accept up to #12 AWG wire.
• Thermal Stability: Operates efficiently in extreme environments from -40 to 185 degrees Fahrenheit.

What is the minimum switching time for this unit?
The Intermatic GMXST-I-120 uses captive trippers to provide a minimum ON or OFF time of 15 minutes within a 24-hour cycle.

Can I use this timer for 240V equipment?
No, this specific model is designed for a 120V AC supply. For 240V applications, use the GMXST-I-240 to ensure proper voltage compatibility.

Is this timer suitable for outdoor rooftop units?
This model comes in a UL Type 1 indoor plastic enclosure. For outdoor installations, the mechanism should be housed in a Type 3R rainproof enclosure.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.