Furnace Blower Motor Capacitor Sizing

The blower motor in your furnace blows hot air through the ducts and into your home.

Furnace blower motor capacitor sizing. It is difficult to find a 40kbtu furnace that can move 1000 cfm at a reasonably high static. Assuming a start up energy of 0 00033 joules you obtain 0 33 divided by 66 1 which equals 5 0 times 10 6 farads. Its capacitor works like a battery and stores the energy needed by the blower to work properly. Where is a furnace capacitor located.

How to read your capacitor voltage and mfd for a replacement capacitors are rated by the. The capacitor will be located close to the blower motor since it is there to help the blower motor run and have wires coming from it. If the furnace is receiving power turn up the thermostat and see whether the blower motor starts within the next few minutes. The start up energy of the motor is found either in its documentation or written on the motor itself.

You can see the listing description the specifications are listed for the motor. To answer this question the panel door to the furnace will need to be removed. Divide the start up energy requirement in joules of the motor by x to arrive at the capacitor size needed in farads. This chart shows the blower details for a 120 000btu furnace.

How to locate a furnace s start capacitor. A bad or faulty capacitor can exhibit many signs and symptoms. If you re concerned that your furnace capacitor isn t operating properly you can test it by following a few simple steps. This unit has a variable speed motor that operates in an operating range configuration.

If not the capacitor or the blower motor is not functioning properly. Box type note icon none operating range blower table. Example furnace blower motor on amazon a o. You simply measure the current amps of the motor start winding coming off of the capacitor and multiply it times 2652 on 60hz power 3183 on 50hz power and then divide that number by the voltage you measure across the capacitor.

Before checking the capacitor make sure the fuse controlling the furnace is flipped to the on position. Here is an example of a furnace blower motor on amazon. A furnace usually uses a run capacitor to maintain a relatively constant voltage supply to the blower motor. The difference is more than 100 times is there a calculation error.

Hvac heating ventilation and air conditioning capacitors store electricity and help compressors and blower motors the systems that distribute hot.