Can be termed control system. This refers to their function, which is to start, stop, regulate and protect the unit. It can be electric, electronic and Pneumatic.
Electrical and electronic are commonly used in the small and medium size jobs. Pneumatic controls are use for larger HVAC-R systems.
SELECTING THE CONTROL SYSTEM
The type of controls selected for any system depends on many factors: The size, the age, the relative cost, the location, the designer’s preference of the equipment.
The preference for electronic controls is the low cost, accuracy and the performance. Regardless of the type of controls, the function performed can be the same in a different way.
TYPES OF BASIC CONTROLS
There are four types:
1) Thermostat is operated by temperature
2) Pressurestat is operated by pressure
3) Humidistat is operated by moisture or humidity
4) Time clock or switch is operated by time
Can be single stage, two stage or multi-stage
MILLIVOLTS systems use a pilot generator that provides an operating voltage of between 185 and 600 Millivolts.
PROGRAMMABLE is good way to control your Heating and cooling. You can program you thermostat to meet your needs in your schedule plan. You can choose the start time, the temperature, and the days for your comfort; it can be set for different temperatures for various periods throughout the week. You will save energy when the space is unoccupied. This system has three selections: Heat, Cooling, and Off. The system is always in either the heating mode or cooling mode, but cannot switch to the other unless the system switch is manually operated. The great advantage of the electronic thermostat is its accuracy.
NON-PROGRAMMABLE you will be able to set the temperature in heating and cooling any time you like. This kind the unit will run only in one temperature until the user will change to different setting point. An example if the user in winter time before goes their work forgot to set the thermostat lower, the unit will run all day and will be not save energy. We recommend to installed programmable or auto-changeover thermostat in your system for comfort and better performance of your unit. This system has three selections: Heat, Cooling, and Off. The system is always in either the heating mode or cooling mode, but cannot switch to the other unless the system switch is manually operated.
AUTO-CHANGEOVER PROGRAMMABLE is the best, this thermostat automatic will change between heating or cooling depends on the space temperature or the weather. The installer will set the programming in the beginning and them the thermostat will take care your comfort in winter or summer.
This system has four selections: Heat, Cooling, Auto, and Off. When the system switch is set in the auto position, the thermostat can provide heating when the room temperature is below a set point and cooling when the room temperature is above a set point.
This type of thermostat is perfect in offices or buildings because the settings of the thermostat can be a source of disagreement among office occupants. Owners will place a locked box around the thermostat so that it cannot be adjusted by the office personnel.
HEAT PUMP THERMOSTAT is specially designed for it. There are a variety of heat pump thermostats. Most air to air heat pumps units use two stage heating thermostat. First stage energizes the refrigeration circuit and the second energize the electric heat. The cooling mode operates like a normal thermostat