Variable Speed

Variable Speed

Your air conditioning technician, when he visits you, may throw around some terms that are very common to the industry but may be very foreign to you or you may have associated with something else entirely.
When variable speed is mentioned by your technician there are two things he could be talking about.
1. Blower motors (the section that moves air inside the house.
2. The pumping action and actual cooling ability of your Air conditioning system
Here are two different breakdowns for you. I have split it into “Red Pill” & “Blue Pill”. Take the Blue Pill for a superficial explanation or take the Red if you’re feeling brave.

What variable speed means for the non technical person:

  1. A variable speed blower doesn’t actually operate on variable speeds other than it slowly ramps up to a preset speed. Your technician can change this speed but he is limited by the size of the system. This Blower will not be slowed down (easily) by restricted duct systems or dirty filters. It’s also much more efficient to operate a variable speed blower motor. It has a tendency to even out the air temperature in your house in some cases.
  2. A variable speed AC system operates variably. The compressor, outdoor and indoor fans work together based on settings in your thermostat. It will deliver variable amounts of “cooling” for your home. This is the most efficient type of system for your power bill and humidity removal. Technology is heading in this direction; airconditioning, cars, drills etc.

What variable speed means to the geek:

  1. A variable speed blower has almost infinite settings. These are preset in the field however. Most systems will ramp up to speed and some of those will actually stage up based on settings that are, most of the time, adjustable in the field. These motors are desirable because it will force the correct amount of airover the coil making your system as efficient as the data plate suggests. This isn’t a fool proof solution, it is still optimum to have the correct size duct system.
    The motor design is  3 phase and utilizes DC voltage that is converted from AC in the air handler. There is more circuitry but it all works to give you more efficiency and comfort. A surge protector is recommended and you can get an electrician to install one for you.
  2. A variable speed system is one where all motor components are variable speed. The compressor starts at say, 20% and stages up 1/2% until 100% is achieved. the compressor can stage up and the blower can lag behind a bit and this produces more humidity removal.
    The condenser motor sometimes (depending on the brand) will be variable speed but preset to 2 speeds and on others will be truly variable.
    These systems require a special thermostat sold by the vendor and as of now you have no options however, they are pretty good thermostats over all. And all are WiFi capable. In all cases the variable speed control is limited to protect the equipment. So the end user doesn’t have full control.
By |2019-06-13T16:11:33+00:00April 24th, 2019|Air Conditioner Maintenance, Air Conditioning Repair|Comments Off on Variable Speed

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