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Maintaining the operation of the boiler, one needs to have in-depth knowledge about the working of the system. When the boiler system is performing adequately, then it means all the components are in the right condition. There are certain parameters involved, and one of the essential parameters is system pressure. The parameter cannot be neglected as it requires multiple pressure monitoring sensors. Therefore, having effective boiler controls ensure the proper monitoring of every part of the system.
In this article, we will understand some of the key boiler controls.
The first spot where you can detect the monitoring capability is the boiler operating control. Generally, the boiler operating controls feature overpressure safety. If the default pressure exceeds, the limit circuit is tripped, which will stop the supply of the fuel to the boiler and thus stop the production of steam. For instance, if your boiler system operates at 120 psi, then the operating control will stop the functioning of the system if the pressure exceeds the normal settings.
➤High Limit Control
The high limit control shield against excessive system pressure. The protection it provides is extra than the operating control cannot offer. However, one needs to do the manual setting when using the high limit control as it won’t allow the boiler to operate till it’s manually reset.
Inside the boiler controls, one can easily see a mercury switch. Some people assume it is an outdated technology; however, it’s an incredible type of switch as it’s reliable. There is no need to learn too many technicalities as the mercury switches operate in an easy manner.
The second reason for choosing a mercury switch is that it offers visual confirmation about the tripped switch. Undoubtedly, mercury is a dangerous substance. So, the new boiler controls use microswitches for maintaining the operating pressures.
➤Firing Rate Controller
The firing rate controller is responsible for maintaining the proper system pressure. It operates with a slide-wire potentiometer. The controller gets the signals which prompt them to operate. When the demand for the system is great, then the fire setting is set high. On the other hand, low fire is set to make sure the burner is at minimum input as the demand of the system is reduced.
➤ Low Fire Hold Controller
Today’s boiler system has a fourth controller, called a low fire hold controller. This controller is designed to be certain that the boiler runs at a low or minimum temperature & pressure before the boiler reaches full power. For instance, when revving a cold car engine, we will put some stress on the parts inside. Similarly, the cold or newly started boiler will put undue stress in the form of thermal shock. However, ensure at a certain point in time, thermal shock can damage the efficiency of the system and make the system unsafe for you.
How the Various Controllers Work Together?
- Firstly the main controllers should be set at the highest preferred operating pressure.
- Ensure to set the high limit controller at a point slightly higher.
- The low fire hold controller is put at the point where your boiler can function the heat properly and all set for taking on the additional load.
- Adjustments need to be made to the firing rate controller according to the boiler’s specifications then the operating control should be adjusted to avoid short cycles or premature shutdown.
- A low fire hold controller is set to prevent damage. Ensure it is not a substitute for manual boiler warming.