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Phone: 540.373.8471
Fax: 540.373.8393
26 Town & Country Drive
Fredericksburg, VA 22405
Specializing In:



We service all makes and models of ACs, heat pumps, and furnaces.

DIY Maintenance Tips

DIY Residential Maintenance Tips:
1)   Filters
2)   Grills, register, and ductwork
    3) Indoor Units
4) Outdoor Units
5) Thermostats & Humidistats
6) Troubleshooting a heatpump    
Remember to keep curtains drawn in the
wintertime--you would be surprised
how much energy it saves!  
Check & change once per month, more often in homes with excessive pet hair. We cannot stress how critically important it is to keep clean filters in your home. Filters do more than maintain good air quality. A dirty filter is like a sock stuffed into the “mouth” of your system. Clogged filters inhibit the ability of your system to get the air it needs to function, causing it to work harder and harder to maintain your desired temperature. Aside from the cost to replace parts that fail from the strain, the overall lifespan of the system is dramatically reduced. But wait—there’s more bad news. Dirty filters will eventually allow particulate matter (dust, dirt, hair, etc.) to pass straight through to your indoor unit’s evaporator coil.  We’ll skip the techno mumbo jumbo and say that is simply VERY bad. If you’re lucky, we can clean the coil to get it back up and running (a time-consuming and pricey fix). More than likely, the coil will become clogged, fail, and need to be completely replaced (and even more time-consuming and even pricier fix). Please note that warranty companies deny claims for systems damaged due to lack of maintenance. 
There is, however, some good news! You do not need to purchase high-end filters that are loaded with anti-allergens, baking soda, etc. Cheap poly filters, changed monthly, are the way to go. We provide filters--at cost—here at our shop.
  • Clean the grills that cover your filters each time you replace a filter
  • Clean floor registers periodically.  While doing this, you can also clean your ductwork by gently inserting a vacuum wand and cleaning the areas that are within reach. 
  • Make sure that all floor and wall registers have plenty of clearance when you rearrange your furniture. 
Aside from producing conditioned air, furnaces and heat pumps also produce condensation. This water collects in the drain pan at the base of the indoor unit, and is subsequently pumped out of your home via a condensate pump and condensate tubing. “Gunk” can build up in the condensate lines, caused by mildew and dirt that has passed through dirty filters. When the condensate line becomes clogged, water will leak from base of the unit. This results in flooring, property, and ceiling damage. Here are some pointers:
  • Change your filters frequently (at least once per month)! 
  • Clean your condensate lines by pouring ¼ cup of bleach into your drain trap (look for the PVC cap coming from the indoor unit).
  • ¼ cup of bleach can alternately be poured into the condensate pump itself—this is the rectangular box located near the base of the indoor unit—most have a round access hole & plug.
  • Gently remove the flexible condensate tubing that comes from the pump, and blow into it.  
  • Ask about having a safety switch installed in your drain pan, which shuts your unit off if the pan gets too full. 
  • Keep all flammable materials away from your indoor unit—this is particularily critical for gas and oil furnaces. 
For heat pumps and straight-AC systems, the outdoor unit (ODU) is the location where fresh air is pulled into your home. The largest component in the outdoor unit is the condensing coil (you can see the coil’s narrow metal fins through the unit’s casing). While the unit sucks in air, it unfortunately also pulls dirt, grass, pet hair, etc. into those fins. Keeping it clean and free of obstructions is as critical as keeping clean filters in your home. The consequences of a dirty ODU are the same as those listed for dirty filters, including home warranty claim denial for lack of maintenance. Here are some pointers: 
  • Protect the outdoor unit by putting up a barrier (such as latticework)—make sure you allow at least 12 inches of clearance on all sides. Also, make sure there are no obstructions within 5-6 feet above the unit to allow for proper airflow from the fan.   
  • Avoid planting shrubs, bushes, or trees near the outdoor unit.
  • Clean the coil by LIGHTLY spraying the ODU with water—SYSTEM MUST BE OFF! Keep in mind that there are electrical components in the unit, so use a light spray only. You can manually remove clumps of hair or debris, but use work gloves and work gently—the fins are sharp and are easily bent.   
  • Pet urine translates to a death sentence for coils. Put a barrier around the unit, and make sure that your pooch doesn’t use your system as a restroom.   
      -  Try to keep your home set at a consistent temperature
          throughout each season.   
      -  Make changes to your temperature setting
         gradually, in 2 degree increments. 

Setting A Humidistat

Generally the comfort range for  humidification is between 25 percent and 50 percent RH.  It is desirable to keep the humidity in the living space within this range as long as condensation does not occur on windows and walls.  The point condensation occurs at, is affected by the building structure and outdoor temperature.  As the outdoor temperature changes, the humidistat should be reset to keep the humidity level in the building below the condensation point.  
The set point scale of the humidistat is indexed directly to the outdoor temperature for convenience.  It is recommended that the humidistat be set to the prevailing outdoor temperature.  This provides optimum humidity control for most installations.
If the proper outdoor temperature setting is used and condensation forms on the windows or walls, reduce the set point 5 F (3 C).  Frost or condensation should disappear from windows within 24 hours; if not, continue reducing the set point until it does disappear.
If the humidistat is set to the proper outdoor temperature and condensation does not occur, the humidity level in the living space may be increased if desired.  Raise the humidistat set point in 5 F (3 C) increments until condensation just begins to appear.  Then reduce the humidistat setting by 5F (3 C). 
The hygrometer indicates the ambient humidity directly in percent RH.  It provides an accurate indication of the ambient relative humidity.
Wall Mount Humidistat
The humidity set point should be set for the prevailing outdoor temperature.  This provides optimum relative humidity control for most installations.  The humidity level may be adjusted to a particular structure by using the above procedure.
Duct Mount Humidistat
  • If the temperature at the humidistat location on the return air duct is less than 80 F (27 C), use the procedure for all mounted humidistats shown above.
  • If the air surrounding the humidistat is greater than 80 F (27 C), the recommended setting should be reset to compensate for the elevated ambient temperature.  High surrounding ambient temperatures will cause the humidistat to control at an increased setting.  To determine the compensated set point for surface mounted humidistats with high ambient temperatures, use the following procedure.
  1. With a bulb type thermometer, accurately determine the surrounding duct temperature at the humidistat location.
  2. Decrease the recommended setting about 10 F (6 C) for each 5 F (3 C) above 80 F (27 C) at the humidistat location.  For example, the outdoor temperature is 0 F (minus 18 C), and the temperature at the humidistat is 90 F (35 C).  The compensated set point should be minus 20 F for the 10 F above ambient temperature (minus 18 C setting minus 12 C for the 8 C above ambient temperature).
Checkout - Place the system in operation and observe through at least one complete cycle to make certain that all components are functioning properly.
Heating Mode
  • Under certain weather conditions, the outside unit will develop ice buildup.
    • When the unit defrosts this ice, it gives off water vapors which appears to be smoke.
    • If excess ice builds up on the outside coil after more than 90 minutes elapse time, switch emergency heat to “ON” (located on the thermostat). 
    • Call your serviceman if the condition does not clear.
  • Auxiliary heat light “ON” (located on thermostat).
    • Supplementary heaters are providing heat (usually when outside temperature is lover than 30 degrees). 
    • Thermostat has been adjusted up more than 1.5 degrees, which causes supplementary heaters to come on until thermostat is  satisfied.
    • If auxiliary heat light stays on when the outside temperature is about 30 degrees, call serviceman.
  • Little or no air flow at supply registers.
    • Filters are dirty—replace.
    • Blower motor or belt failure.
    • Possible air leak from ducts.
    • Return grill blocked
  • Outside unit continuously running in moderate weather. (All units run continuously below the balance point, usually when outside temperature is lower than 30 degrees).
    • Thermostat set too high.
    • Thermostat needs adjustment.
    • Low refrigerant level in unit.
    • Outside unit coil blocked by snow, ice, etc.
Cooling Mode
  •  Outside unit continuously running.  
    • Low refrigerant level in unit.
    • Thermostat set very low or very warm weather.
    • Outside coil partially blocked.
    • Thermostat located near heat source, such as appliances, TV, etc. 
    • Dirty Filters or too many registers closed limiting air movement
  • Unable to cool house and reduce humidity level.
    • Condensation drain blocked.
    • Low refrigerant level in unit.
    • Possible compressor failure.
    • A door or window open.
    • Check for air leaks and excessive moisture in crawl space.
If ever in doubt, call us at 540-373-8471—advice if free! 


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