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White rectangular wall thermostat with digital display and temperature controls

Q-Mark

Q-Mark SPST Thermostat 240/208V AC UH724ST

SKU CH-AJJK-3JKM6

SPST thermostat for 240/208 V AC electric space heaters, wall-mounted with Fahrenheit scale and cULus listing

  • Product typeLearning Thermostats
  • SPST switching for simple on/off control of electric space heaters
  • 240/208V AC rating matches common commercial heater circuits
  • Wall-mount design allows convenient placement in workspace or garage
  • cULus listed for compliance with North American safety standards
  • Compatible with Grainger part numbers 3UG73 and 3UG74 for easy replacement

Single-pole thermostat for electric heaters

The Q-Mark SPST thermostat controls 240/208V AC electric space heaters. It mounts on a wall and displays temperature in Fahrenheit. The unit carries a cULus listing for safety compliance. It replaces Grainger part numbers 3UG73 and 3UG74.

Installers wiring single-pole heater circuits

This thermostat suits contractors and facility staff who need a basic line-voltage switch for one heater circuit. It will not serve systems that require double-pole switching, multi-stage control, or smart-home integration. Buyers needing programmable schedules or remote access should look at a different model.

Simple two-wire line-voltage installation

Power must be off before connecting the two line wires to the SPST terminals. A common error is wiring the device on a circuit that exceeds the 240/208V AC rating or using it on a low-voltage system. Verify the heater voltage matches the thermostat rating before closing the wall plate.

How it compares

Measured against everything we stock in Thermostats & Thermostat Accessories, at today’s prices. Recalculated every night.

Price $32.99
Cheaper than about 73% of the 286 comparable items (median $78.49).

Specifications

Product
Brand nameQMARK
Product typeLearning Thermostats

Questions about this item

Does this thermostat control a 240 V or 208 V electric space heater?

It is rated for both 240 V and 208 V AC electric space heaters.

Will the SPST switching work with my existing two‑wire heater circuit?

Yes, the single‑pole single‑throw action opens or closes the two‑wire line to the heater.

How can I confirm the unit is operating correctly after wall mounting?

Set the Fahrenheit dial above room temperature and verify the heater activates, then lower it to confirm shut‑off.

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