Thursday, 13 June 2013

Should You Replace Your HVAC Blower Motor for Higher RPMs?

During the cold season, every home’s furnace takes a lot of beating and abuse as components like the blower motor is always in constant operation while warming the indoors. This is when the blower motor can become worn down internally due to age, operation and lack of lubrication, which in turn causes a major decline in hot air movement in the home’s ductwork. A practical solution to an inefficient blower motor is obviously replacement. 

Before replacing a HVAC blower motor, you need to make sure that the circuit breaker at the electrical panel which supplies power for the furnace to work needs to be shut off. The motor is normally connected to the home's main electrical supply and touching the components of the furnace with the electricity on can cause electrocution. To determine if the circuit wire is live or off, you can use a non-contact circuit tester directly on the blower motor's wiring. Then the tester should be pressed against the wires to make sure that there is no danger of electrocution in case any work is undertaken on the motor. The motor resembles a small barrel with three wires extending from its housing and is usually lodged behind the furnace's protective outer cover. Before cutting or removing the wires, you should make a note of the motor's wire color connections to the furnace. It’s also important to note that every manufacturer will have a different strategy for wire connection, so it’s imperative that you go through the furnace system’s manual before undertaking any work. 

The blower motor is fastened inside the assembly, so once the motor's wheel is located within the blower, the set screw can be removed and the motor pulled away from the blower assembly. This is the major component that must be replaced. The new motor should be installed in the reverse process before removal of the old part. The most important thing is that the new blower motor should be compatible with the blower assembly in specifications and values related to voltage, speed, horsepower, rotation direction and motor diameter of the old motor in order to function effectively. There are many who question if they can use blower motors with higher RPMs in their furnace to make it work better and more efficiently. However, most modern HVAC systems are properly designed to match the airflow through the heating coils for the expected temperature drop. Changing the CFM without knowing the design point of the coil may prove to be a really bad idea as it can negatively impact the unit's performance. Most technicians say that once you start messing with the CFM of a furnace system then it’s most likely to drop its moisture control capacity, increase noise and power consumption or even cause worse problems for the system’s working condition. 

Some of the main disadvantages of replacing a blower motor with higher RPM are as follows:-
  • The functioning of the system will get too noisy
  • The blower wheel is likely to self destruct
  • Turning the existing wheel of the system with a higher RPM will require more horsepower. It can also draw higher amps or burn itself up.
  • A HVAC blower motor should always operate in a specific CFM range that is designed based on its capacity. More airflow cannot be necessarily better, and may get worse.
Many homeowners feel that increasing the RPM of the motor will increase airflow throughout the house thereby providing a warm environment in less time. However the truth is that replacing an existing blower motor with that of a higher RPM is no big deal as the issue with more air flow can simply be addressed by added insulation and adjusting the dampers of the closer rooms.

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