Below are the definitions of some common terms relating our thermostats.

Automatic Reset:  A type of thermal switch that will reset itself at a specific temerpature (i.e. a switch opens at 150°F and closes or resets at 120°F)

Bimetal: Two dissimilar metals bonded together to form the disc which actuates the temperature switch; upon reaching a specified temperature the disc snaps over the center.

Close On Rise: (COR) Refers to the operation of the contacts.  When the temperature rises to its set point the contacts close or make contact and complete the circuit.

Max. Differential: The maximun allowable difference between the actual opening and the actual closing temperatures.

Mean Differential: The difference between the upper and lower nominal set points without regard for tolerances.

Min. Differential: (Sometimes called “Deadband”) The minimum allowable difference between the actual opening temperature and the actual closing temperature.

Open On Rise: (OOR) Refers to the operation of the contacts.  When temperare rises to its set point the contacts open, terminating the circuit.

Set Point: The nominal temperature at with the thermostat switch is open or closed.

Tolerance: The allowable range above and below the set point (typically +/- 5°F)

Here are some pictures showing how various systems may be laid out using our new Thermostat Powerstrip.

Each concept works great with our Temperature Switches (or Thermostats) as well.  Of course, you’d just have to mount the switch and wire it to the device that’s shown as plugged into the  powerstrip.

Here a temperature switch (prewired into a powerstrip)  triggers a booster fan that will help disperse the heat around the room.  Typically the thermal switch is placed near the heat source and kicks on when it senses heat being produced.

Put a temperature switch (or powerstrip) along the coldest stretch of pipe , or where it will cool before the pipe does.  Connect the heating tape to the thermal switch and voila! protection against freezing.  Of course, there may be other things that need protection from the cold.  We recently heard of a customer using a temperature switch to protect the charge in his solar battery.

Having the temperature switch and timer in tandem ensures that you won’t waste energy competing with natural ventilation when it is working well or needlessly running the fan when the air temperature is not ideal.

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Information on temperatures & mounting options can be found here.

We recently had a customer ask if our parts were made in the USA. The simple answer is Yes – absolutely.

The detailed answer is: All of the final assembly is done in the US and almost all of the parts come from the US. As one example of the parts distribution, for our 2511 line: Of the twelve components, one part comes from South Korea and another from a vendor that just moved their production to India. The other ten parts are either made in-house or supplied by a US manufacturer. This works out to around 2% of the total cost from overseas parts and 98% of final production and first level fabrication done in the US. That said we have a number of very good vendors from other countries that do a great job.

We get lots of questions on the temperature choices of bi-metal thermostats. I’ll try to answer a few of those here:

*How accurate are the thermostats?

We have two general specifications on the thermostat temperatures. One style uses a plus or minus some tolerance, typically 3-7ºF per temperature. So, if we say the device opens at 95ºF it will open between 90 and 100ºF (with the most common +/- 5º setting)

Our other style is called a min/max and for those units we just specify the outer temperatures with a 10 or 15 degree hysteresis. For example as 125-115 min/max open on rise switch will open by 125 and close by 115. Generally these would open around 122 to 125 and reset by 118 to 115. However, they may change at 122 and 120 giving a small hysteresis as well.

Custom tolerances are easily available to help manage your thermal systems. Also, for all of our units these temps are accurate to 0.5ºF degrees and are calibrated to NIST standards.

* What happens to the system if the temperature I’m controlling is off by a few degrees?

If failure to get the temperature right means the system will be damaged severely (frozen pipes) add some gap between the danger zone and the thermostat setting. The thermodynamics of systems can change with air flow, humidity and other factors so from a simple design standpoint it may never get to the danger zone but in the field odd combinations of conditions might cause problems.

* Why doesn’t the temperature I select work the way I want it to?

Sometimes the temperature sensor is placed in a central location but there may be hot or cold spots in the system that aren’t the same temperature. In these cases make sure to add a couple degrees to your specs to account for that thermal difference. If you are protecting pipes from freezing there may be an elbow or other feature that gets extra cold compared to the rest so the thermostat may see 35 degrees but down the pipe a bit is a cold spot that will still freeze before the thermostat is triggered.

For accurate measurement metal to metal contact over a large surface area is generally best. Air to metal contact is good if there is some airflow around the thermostat, the more airflow the better. If the thermostat is measuring air that is not moving there will be more lag between when the air gets to your target temperature and when the thermostat gets to that temperature. If you have a system element that is changing the air temp that you are then measuring there will be a lag and a gap in temp between the system element and the thermostat.

* How small can the hysteresis be?
For these types of switches 10ºF is about the smallest range they can maintain cost effectively and consistently.

For complex systems actual testing is usually pretty important. We support this process my making it easy to test multiple package styles and disc temps in sequence or all at once just give us a call.