Operation of the blower fan
Thread Content
When starting a point heating furnace, should the blower be turned on first or the exhaust fan? If the blower doesn’t work, can the exhaust fan still start?
First, start the exhaust fan to create negative pressure, then start the blower; it is possible to start the blower without starting the exhaust fan
Is there an interlock between the blower and the exhaust fan?
Also, if the blower stops, can the device still operate normally?
Everything should be carried out in accordance with the operating procedures; such matters require flowcharts and process conditions to be discussed. The principle behind both drawing in air and forcing air in is the same: to control the flow rate of air according to a predetermined process as needed. If the airflow volume can be controlled to reach the outlet smoothly, then this exhaust fan is not necessary. If your air intake capacity is sufficient to ensure that the amount of air at the intake location meets your requirements, then this blower is not necessary.
In my view, the direct function of a forced draft fan is to enable waste heat recovery and increase the efficiency of the furnace. If you want to drive a fan, just think in terms of waste heat recovery
The blower is used to supply the oxygen required for fuel combustion, while the exhaust fan ensures that the exhaust gases from combustion are removed from the furnace properly, simultaneously maintaining an appropriate negative pressure inside the furnace to guarantee its safe operation.
Generally, no interlock is provided between the blower and the exhaust fan. Furnaces equipped with a blower are designed to have quick-opening dampers, and in the event of the blower stopping, the interlock will open these quick-opening dampers.
I think the blower should be turned on first, followed by the exhaust fan.
Starting the blower first will create a positive pressure in the furnace, causing air to leak out from all sides. This is fine when the furnace is cold, but it becomes very dangerous when it is hot.