Two Stage Heat / Heat - Cool Programmable Thermostat (Includes 079 Sensor) Zoom

Two Stage Heat / Heat - Cool Programmable Thermostat (Includes 079 Sensor)


Brand: Tekmar

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Application: Multi Stage (Heat/Cool)
1 Heat/1 Cool
1 Heat
2 Heat
Programmability: 7 Day
User Interface: Push Button
Mount: Horizontal
Options: Fan Control
Large Display
Comes with Sensor
Power Method: Hardwired
Temperature Range (F): 40 to 95°F (Heating)
50 to 100°F (Cooling)
Low voltage
Color: White
Height: 3-11/16"
Width: 3"
Depth: 15/16"
Weight (lbs): .6
Ambient Conditions: 32 to 122°F (0 to 50°C)
RH ≤ 90% non-condensing
Control: Microprocessor PID control
Enclosure Type: Nema 1
Sensors: NTC Thermistor
10 k ohm @ 77°F
Floor Sensor Compatible: Yes
Humidity Control: No
Wireless: No

Description for Tekmar 521

The Programmable Thermostat 521 is designed for three different modes of operation: single stage heating, two stages of heating with a fan, or one stage of heating and one stage of cooling with a fan. Two auxiliary sensors may be added to measure the floor, outdoor or room temperature. A Slab Sensor 079 is included to measure floor temperature to protect the floor from overheating and enhance comfort. The programmable schedule supports either a 7 day or 24 hour schedule with 2 or 4 events per day. A permanent temperature hold button overrides the programmable schedule. An optional Adaptor Plate 012 is available to allow the thermostat to mount onto a single gang electrical box.


  • 7 Day Programmable Schedule
  • Backlight
  • Cooling
  • Fan
  • Four Hour Battery-free Clock Backup
  • Optimum Start
  • Outdoor and Floor Temperature Display
  • Permanent Temperature Hold
  • Radiant Floor Heating
  • Time Clock
  • Two Stage Heating

Two Stage Heat / Heat - Cool Programmable Thermostat (Includes 079 Sensor)


by PowerReviews
TekmarTwo Stage Heat / Heat - Cool Programmable Thermostat (Includes 079 Sensor)

(based on 1 review)

Ratings Distribution

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Reviewed by 1 customer

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Excellent Thermostat

By Russ

from Jonestown, PA

Verified Buyer

Comments about Two Stage Heat / Heat - Cool Programmable Thermostat (Includes 079 Sensor):

This thermostat replaced three different thermostats that I was using for the in floor radiant heat in my shop.
I had one thermostat to conrol the maximum floor temperature. One thermostat to control the air temperature and one thermostat to control the auxialry electric forced air heat. The Tekmar thermostat controls all three of these with just one unit and does a better job at it.

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  • Two Stage Heat / Heat - Cool Programmable Thermostat (Includes 079 Sensor)


    Can you program this thermostat using the floor sensor only. It states that it monitors the floor, but doesn't say if it will call for or shut off heat from the floor.
    Asked on 4/30/2015 by AJ

    1 answer



      Yes it can, but that needs to setup in one of the back end settings screens

      Answered on 5/1/2015 by Supplyhouse Staff from New York
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