How Thermostats Work

A thermostat is an instrument used for the regulation of temperature that is given out by another system in a given area. Its main function is to maintain a desired temperature. Essentially, thermostats are used in at least two ways: by making it a component part of a heater or an air conditioner or by being a separate control unit for a heating or cooling system.

How Does a Thermostat Work?

The basic thermostat works by turning on the heater when the temperature drops below a given temperature and by turning it off when the temperature rises above a certain number. The desired temperature is called the “set point.”

Thermostats are made up of different parts to make them work, and the most fundamental of these is the mercury switch. This is a glass vial that contains a bit of mercury. Mercury is a liquid metal which conducts electricity and flows like water. The glass vial has three wires inside. One leads to the bottom of the vial to be able to maintain a connection with the mercury. Another wire goes to the left part of the vial, so that when the vial tips to the left, the mercury can still touch it. With these positions, you’re assures that the mercury has contact with both ends of the wires. The third wire, on the other hand, goes to the right side of the vial. This spot is a strategic position to be able to have contact with the mercury whenever the vial tilts to the right. This position also ensures that contact occurs between the bottom wires and the mercury. It is important that connection with the mercury is maintained so that accuracy may be achieved in the heating and cooling off process.

There are two thermometers in thermostats: one in the cover, which displays the temperature reading and another at the top layer of the device, which regulates the heating and the cooling systems. The thermometers are coiled bimetallic strips which are made of two different kinds of metals that are laminated together. These metals expand and contract when they are heated or cooled accordingly. These expansion and contraction of the metals are the mechanisms that move the temperature-adjustment lever. The movement that they make will touch the mercury switch to read a certain measure.

There are also two switches that are included in working thermostats. One switch regulates the temperature, which is called the mode, and the other controls the circulation fan.

The Most Common Types of Thermostats

There are at least three types which you could choose from: the Electromechanical thermostat, the Digital Manual thermostat, and the Digital Programmable thermostat.

The Electromechanical thermostat is the oldest kind of these devices. They work with the use of mercury, as previously described. Even with the more modern types and designs, this type is still popular and widely utilized because they are cheap and simple. The primary disadvantage of an Electromechanical thermostat, however, is it’s less accurate than the digital ones and they are not programmable.

The Digital Manual thermostat works like the electromechanical thermostat, but without the mercury and with the coiled bimetallic strips substituted by an electronic temperature sensor. It has a microprocessor inside that makes the comparison between the sensor reading and the set point that you selected. The microprocessor then gives the start and stop commands to the heating and cooling systems to rise and dip depending on your desired temperature. With the Digital Manual thermostats, setting the desired temperature is still done manually. But because they contain no mercury, they are more environmentally friendly and are better than the electromechanical thermostat.

The third type is the Digital Programmable thermostat. This one works like the Digital Manual thermostat, except that they are more convenient. It comes with a memory unit that programs your desired temperatures at certain points during the day. This kind of thermostat can customize its operation to suit your schedule and way of life. Once you have programmed the certain set points that are based according to your comfort and convenience, you may leave it and go on with your own activities. You will have to program your thermostat once, until you feel the need to change the programmed temperature and schedules.

There are four ways by which you can program your thermostat. First is the 1-day programming. The desired temperature can be set to change automatically during the day. Second is the 5-2-days programming. The set points can be set to change throughout the day, and you can make separate programs for weekdays and weekends. Third is the 5-1-1-days programming. You can program different set points during the day and you can have independent and distinct programs for weekdays, Saturdays, and Sundays. Last is the 7-days programming. You can set your preferred temperatures throughout the day, plus you can fix different programs for each day of the week.

Installation of Thermostats

Thermostats nowadays have been made simple and easy to install. However, if you are not used to setting them up, you may just hire a professional to install your thermostat for you.

In the installation of your thermostat, there are a few guidelines that you must follow for a safer and successful project. The first thing that you must consider is to have the correct thermostat for your heating or air conditioning system. There are many kinds of thermostats and each kind fits a certain system. Second, you must place your thermostat away from the cooling or heating instruments to avoid short cycle. Short cycles tend to shorten the life of your thermostat because of many starts and stops that can be irritating.

The single zone and the multiple zones systems must be used appropriately. The single zone system is definitely improper in larger areas or in a location with various rooms. The multiple zone’s system is the better choice for these areas to allow the various rooms to maintain different temperature and to be able to turn on and off the operation of the thermostat whenever it becomes necessary.

Thermostats must be placed in areas where people spend the most time. It must be located five feet above the ground to be reachable to the average person.