Mars 33243 SPST Thermal Time Delay Relay 24V Electric Heat Sequencer

The Mars 33243 is a single pole single throw (SPST) thermal time delay relay designed for electric heat sequencing and fan control applications in HVAC systems. This relay operates by means of a solid state PTC (positive temperature coefficient) device which heats up as current passes through it, causing a positive snap-acting disc to make or break the necessary contacts.

Key Features:

• 24V control voltage with SPST normally open (NO) configuration
• Adjustable timing: 1-60 seconds on delay, 1-45 seconds off delay
• 25 amp FLA rating at 240V
• Shock and vibration resistant internal snap action automatic reset switch mechanism
• Non-positional mounting for flexible installation
• Voltage and ambient compensated operation
• Ambient temperature range: -50°F to 165°F
• UL and CSA listed for safety compliance

Used for electric heat, air conditioning, heat pumps, gas and oil furnaces, unit heaters and commercial refrigeration applications. The solid-state PTC technology provides reliable, maintenance-free operation with positive make/break action for consistent performance in demanding HVAC environments.