Podcast
Questions and Answers
What is the major difference in the primary sensing elements between steam boilers and hot water boilers?
What is the major difference in the primary sensing elements between steam boilers and hot water boilers?
- Steam boilers require temperature-sensitive sensors, while hot water boilers require flow rate sensors.
- Steam boilers require temperature-sensitive sensors, while hot water boilers require pressure-sensitive sensors.
- Steam boilers require flow rate sensors, while hot water boilers require pressure-sensitive sensors.
- Steam boilers require pressure-sensitive sensors, while hot water boilers require temperature-sensitive sensors. (correct)
In two-position firing rate control, what is the cut-in point for the burner in the case of steam boilers?
In two-position firing rate control, what is the cut-in point for the burner in the case of steam boilers?
- 50 kPa
- 35 kPa (correct)
- 100 kPa
- 70 kPa
What is the primary manipulated variable in steam boiler control systems?
What is the primary manipulated variable in steam boiler control systems?
- Steam pressure
- Airflow
- Firing rate (correct)
- Fuel flow
Why is two-position control only used in smaller capacity boilers?
Why is two-position control only used in smaller capacity boilers?
What happens when a hot water boiler continues to fire at an excessive rate?
What happens when a hot water boiler continues to fire at an excessive rate?
What is the primary focus of this chapter?
What is the primary focus of this chapter?
Which code most suitably addresses automatic firing rate controls for boilers?
Which code most suitably addresses automatic firing rate controls for boilers?
What is the purpose of firing rate controls in boilers?
What is the purpose of firing rate controls in boilers?
In the event of an operating control failure, what must high limit controls be able to do?
In the event of an operating control failure, what must high limit controls be able to do?
What must the energy output of a boiler always equal?
What must the energy output of a boiler always equal?
What is the purpose of high-low firing rate control in a boiler?
What is the purpose of high-low firing rate control in a boiler?
Why do high-low boilers require two operating pressure controls (pressuretrol) instead of one?
Why do high-low boilers require two operating pressure controls (pressuretrol) instead of one?
What happens when the low-fire burner circuitry is energized in a high-low boiler?
What happens when the low-fire burner circuitry is energized in a high-low boiler?
In a multi-position firing rate control, what happens when the load demand increases?
In a multi-position firing rate control, what happens when the load demand increases?
What makes fully modulating firing rate control different from high-low and multi-position firing rate control?
What makes fully modulating firing rate control different from high-low and multi-position firing rate control?
What causes mercury switches to occasionally fail?
What causes mercury switches to occasionally fail?
What type of switches are used instead of mercury switches?
What type of switches are used instead of mercury switches?
How does the high-pressure cut-off (HPCO) differ from the operating pressure control?
How does the high-pressure cut-off (HPCO) differ from the operating pressure control?
What is the purpose of the high-temperature limit control for hot water boilers?
What is the purpose of the high-temperature limit control for hot water boilers?
How is the high-temperature cut-off (HTCO) different from the operating temperature control?
How is the high-temperature cut-off (HTCO) different from the operating temperature control?
What is the purpose of limiting the boiler to low-fire when starting up a cold boiler with fully modulating firing rate control?
What is the purpose of limiting the boiler to low-fire when starting up a cold boiler with fully modulating firing rate control?
What type of control devices do hot water boilers with fully modulating firing rate control use to control the firing rate?
What type of control devices do hot water boilers with fully modulating firing rate control use to control the firing rate?
What type of switches are used as operating pressure controls, low fire controls, and high-pressure cut-offs in two-position (on-off) steam boilers?
What type of switches are used as operating pressure controls, low fire controls, and high-pressure cut-offs in two-position (on-off) steam boilers?
What is the purpose of the high-pressure cut-off control in hot water boilers with fully modulating firing rate control?
What is the purpose of the high-pressure cut-off control in hot water boilers with fully modulating firing rate control?
What is the purpose of the pressuretrol in a steam boiler equipped for fully modulating firing rate control?
What is the purpose of the pressuretrol in a steam boiler equipped for fully modulating firing rate control?
What is the purpose of the manual reset button on the high-temperature cut-off (HTCO)?
What is the purpose of the manual reset button on the high-temperature cut-off (HTCO)?
What is the purpose of a modulating pressure control in steam boilers with fully modulating burners?
What is the purpose of a modulating pressure control in steam boilers with fully modulating burners?
In hot water boilers with fully modulating burners, what is the purpose of a modulating temperature control?
In hot water boilers with fully modulating burners, what is the purpose of a modulating temperature control?
What is the function of a modulating motor in electrical control systems for boilers?
What is the function of a modulating motor in electrical control systems for boilers?
Why might some larger boilers use two modulating motors?
Why might some larger boilers use two modulating motors?