Temperature Differential of Weatherproof Line Voltage Thermostats

Temperature Differential

As you are choosing the best product for your application, you will notice that we talk a lot about temperature differential, or hysteresis, with our line voltage thermostats. So, what is it? When a switch changes states from Open to Closed. The difference between those two points is the differential, or hysteresis. Here’s an example…

A line voltage thermostat kicks your fan on once air temperature rises to 70°F (contacts close), and once the air temperature falls to 65°F the fan turns off (contacts open). Given this example, the differential of the line voltage thermostat is 5°F.

Line Voltage Thermostats Differential

Our line voltage thermostats are available with a fixed temperature differential of 2°F.

Our Tempro brand of line voltage thermostats offer an adjustable differential up to 12°F.

Additionally, our electronic temperature controller offers an adjustable differential up to 30°F.

For more information about differential and/or our thermostat products, click here or contact us at 715-831-6353.

Variable Fan Speed Control in Greenhouses

Fan Speed Control Automates Greenhouses

Proper ventilation of a greenhouse provides fresh air to plants and cooling. If ventilation isn’t put into place, the greenhouse becomes a furnace from storing heat from the sun. By putting a ventilation system into a greenhouse, you are able to blow out hot air and bring in cool air. Using a variable fan speed control automates a ventilation system preventing heat loss in the colder months for a consistent temperature inside the greenhouse for healthier plant growth.

The K-Kontrol variable fan speed control lets you manually adjust the fan speed from 30% to 100% of output capacity, and turns fans on and off. Because the controller comes in a weather proof enclosure, it is ideal for outdoor environments, but also functions indoors.

Our weatherproof fan control is great for direct control of 120v fans/ventilators. Works great on ceiling fans with the ability to control 3-5 fans depending on ratings. The fan control is commonly used in the winter when less ventilation is required and too much cold air flow can harm greenhouses.

For more information about our fan speed control, choose a product below to visit the product page.

Prewired Variable Fan Speed Control    Variable Fan Speed Control

Wiring a Line Voltage Tstat

The K-Kontrol line voltage tstat is designed for reliable use in heating, ventilating and refrigeration applications. The thermostat has three contact points. Most of our thermostats are wired for heating, unless specified otherwise. When you open the thermostat you should see a white wire that is at blue dot and another wire at the red (heating). The red is your power – do not move this wire. The wire on the blue dot needs to be moved to the yellow dot to be wired for cooling. Continue reading below for more information and illustrations.


All wiring should be done in accordance with applicable codes, ordinances and regulations. Use a disconnect device and overload protection to assure safe installation complying with local and national codes. Figures 1, 2 and
3 illustrate typical wiring for control of heating, cooling, refrigeration, and
combination heating/cooling control systems (use copper conductors only).

General Wiring

1. Remove the four screws securing the cover to the thermostat, and take the cover off.
2. Connect wires to the appropriate terminals (heating or cooling). See wiring diagrams.
3. Place cover back on thermostat for safety.
4. Connect power supply.
5. Tighten screws on thermostat cover.
6. Turn the dial so that the desired temperature is in front of the pointer.

Checking WiringThermostat Wired for Cooling

• Turn dial to 110°F. (heating mode) device should come on, (cooling mode) device should be off.
• Turn dial to 30° F. (heating mode) device should cut off, (cooling mode) device should come on.
• As the dial passes current room temperature, you should hear a faint click from the line voltage tstat.

Switching Between Heating & CoolingExample Line Voltage Tstat Wiring

1. Disconnect the power supply.
2. Remove the four screws securing the cover to the thermostat, and take the cover off.
3. Switching to cooling mode: Remove the wire connected to the heating terminal & connect it to the cooling terminal.
Switching to heating mode: Remove the wire connected to the cooling terminal & connect it to the heating terminal.

For more information or troubleshooting support, click here to review the instructions.

Manual Thermostat Controllers Automate Greenhouse Systems

Thermostat Automates Greenhouse

Automate your greenhouse heating and cooling systems with our quality manual thermostat controllers including wired and plug-in thermostats.

During the cold winter months it can be a struggle to maintain temperatures in  your greenhouse or growing structure.  Using our durable manual thermostat controllers, installation and execution to regulate warmth is simple!

The manual thermostat controllers make it easy for you to control the temperature to match your greenhouse needs if you’re choosing to use an electric heater.

Additionally the thermostat has an automatic shutoff to prevent overheating to keep your plants protected from cold and hot temperatures! By adding an electric heater with a thermostat controller, you can enjoy growing all year long!

Selecting the right thermostat, locating it to sense plant temperature and maintaining the thermostat can save considerable fuel and electricity.


When selecting a thermostat for use in the greenhouse, look for the following:

  • Moisture and dust-tight boxes
  • Capillary tube filled with a liquid or gas that expands to activate the switch

Click here to see our product catalog.


Proper installation can also have an effect on thermostat operation. The thermostat must feel the air that the plants feel if you want to control the temperature in the plant zone.

The best locations are:

  • At plant height near the center of the greenhouse
  • Mounted on an end wall or sidewall of the green house
  • Not directly above heat pipes or in the direct line of a heating duct outlet
  • Shade the thermostat so it is out of direct sunlight

Once the thermostat has been located in your greenhouse, setup to your heater is simple!

If purchasing a thermostat with piggyback plug, like this one, then follow these instructions:

  • Plug the heater power cord into the thermostat plug
  • Adjust the thermostat dial to the desired temperature (60°F) when you want the thermostat to turn on the heater. Please note the KKontrol thermostat will auto shutoff your heater once temperature rises 3°.

If without a piggyback plug, like this one, then follow these instructions:KJ16110 Weatherproof Line Voltage Greenhouse Thermostat

  • Wire the thermostat directly to the heater
  • Adjust the thermostat dial to the desired temperature (60°F) when you want the thermostat to turn on the heater. Please note the KKontrol thermostat will auto shutoff your heater once temperature rises 3°.

Click here to see the complete instruction manual.


All thermostats should be checked for accuracy at least once a year. They can get out of calibration due to dust and dirt on the sensor.

  • Clean the sensor with a can of compressed air and wipe if there is still dirt on it.
  • Set the dial to below room temperature for 10 minutes.
  • Slowly raise the dial setting until it just makes contact.
  • Check this against an accurate wall or digital thermometer. If there is a difference, mark it and have the service person make adjustments the next time the furnace is serviced.

Slash energy costs and receive the maximum benefits year round inside your greenhouse by using KKontrol thermostats.

Choose from a variety of dependable and precise thermostat controls below.

Portable Thermostat Controller         Weatherproof Line Voltage Thermostat

Portable Line Voltage Thermostat Piggyback Plug

Portable PreWired Thermostat

Portable Line Voltage ThermostatCertain K-Kontrol thermostats are supplied with a cord and series plug for easy connection to a 120V AC grounded receptacle. Hang the portable line voltage thermostat near a 1 20V three prong receptacle with a ground pin using the hanging wire included in the package. Plug the male prongs into the receptacle and then plug the controlled equipment into the female part of the plug. If an extension cord is required use only one with a grounded 3 prong plug and 14 gage wire.

Three different varieties are available for purchase online. Click here to learn more!

The K-Kontrol portable line voltage thermostat creates an easy plug-and-play solution. These thermostat controllers are commonly found in barns, greenhouses, garages, vacation homes, construction sites, RV’s, basements, computer rooms and more. They aren’t effected by surges, lightning strikes or power outages like a digital thermostat. It can be used anywhere you have a 120 volt outlet as the clear cover protects from weather and damage.

For more information about our Portable line voltage thermostats, click here!

Weatherproof Line Voltage Thermostats Protect Water from Freezing

de-icer thermostat applicationOur NEMA 4X weatherproof line voltage thermostats are commonly found in outdoor settings such as de-icers! The thermostat controller measures air temperature to turn on a de-icer when the temperature falls below a set point (0°F-80°F). For more information about the lower temperature thermostat, contact us!



Simply plug the power cord from the controller to a grounded 120V outlet, set the temperature you wish the de-icer to come on using the dial, and plug the de-icer into the controllers piggyback plug. When the ambient air temperature falls to the desired set point the thermostat turns the de-icer on. When temperature rises +3° above the set point, the thermostat will automatically turn the de-icer off. De-icer manufacturers recommend setting the dial at 30°F to kick on the equipment when air temperature is below freezing.

De-icers move warm water from the bottom of a pond, lake, etc. creating an ice-free space around boats, docks or other water. In addition to protecting personal property, the thermostat helps protect fish and other aquatic animals. For more information about de-icers, check out a video here!

Portable PreWired Thermostat

Line voltage thermostats uses a liquid-filled sensing element and capillary. There is an exposed or concealed set point dial with adjustable differential, and it will switch line voltages.

K-Kontrols offers both a single stage, heating or cooling, temperature control and a two stage. The two stage line voltage thermostat has two single pole, double throw switches that uses a liquid filled sensing element and capillary.

For more information about the line voltage thermostats for outdoor settings, contact us!