Tuesday, 26 November 2013
Lance Waterbarger's Fall Maintenance Secrets


Nashville Interstate AC Service's technician, Lance Waterbarger, reveals
seven secrets as he performs a fall maintenance check on a 19-year-old Ruud air
handler installed in a customer's attic. The air handler uses both a heat pump
and a bank of two electric heaters. Lance explains how ice forming on the outside
coils is removed by reversing the heat pump and using the electric heaters to keep
the room air warm. Below are some of the checks Lance does as part of Interstate
AC Service's fall preventive maintenance service.

  1. The voltage across the capacitor is checked to see if the capacitor is good.
  2. All wiring connections are checked to be sure they are tight. In this instance,
    a transformer has been replaced at some point in the past and a fuse was
    added. This is smart, because it's better to replace a simple fuse than buy
    and install a new transformer in the event there is a short in the low voltage circuits.
  3. The blower motor bearings are checked for play, to see if the bearings have worn out.
  4. Turn on the heat and put it in emergency heat mode to test the heat banks. The
    amperage draw is checked for each heater. Since the amperage draw is considerable,
    you want a short time delay between the first and second heat bank coming on, to
    avoid dimming the house lights.
  5. The heat bank sequencer is checked for proper operation. The two heaters should come
    on in staggered fashion. Generally, you'll have a 3- to 5-degree swing between first and
    second stage heat. When the first stage comes on, it goes into defrost mode in order to
    melt the ice on the outside coils.
  6. Check that the heaters come on during the outside unit defrost mode.
  7. Check that the outside unit reversing valve works in defrost mode. The outdoor coil
    freezes up in heat mode and there is a sensor on the line that will indicate when it needs
    to thaw the coil. It has a timer or a demand control board that will switch the reversing
    valve, turn the heaters on and turn off the outdoor condensing fan. This traps the heat and
    melts the ice off the coil. When the sensor senses that the coil is approximately 50-55
    degrees, it will kick in automatically back to your regular heat cycle.

Other checks (not seen in this video) which are part of our preventive maintenance service include:

  • Inspecting all air filters.
  • Checking whether the blower belts are worn out.
  • Checking the thermostat for proper operation and settings.
  • Checking and cleaning the condensate drain.
  • Checking all safeties on the unit.


Posted on 11/26/2013 3:00 AM by Eddie Hutton