Figure 7-9.A floor-mounted air-conditioning unit.
renewed or cleaned weekly or more often if necessary.
Always stop the blower when changing filters to keep
loose dust from circulating through the system. When
the filters are permanent, they should be returned to the
shop for cleaning. At least once a year, the unit should
be serviced. When the unit is designed with spray
humidifier, spray nozzle, water strainers, and cooling
coils, each device should be cleaned each month to
remove water solids and scale. Cooling coil casings,
drain pans, fan scrolls, and fan wheels should be wire
brushed and repainted when necessary. Oiling and
greasing of the blower and motor bearings should be
performed as required.
A heat pump removes heat from one place and puts
it into another. A domestic refrigerator is a heat pump
in that it removes heat from inside a box and releases it
on the outside. The only difference between a
refrigerator and a residential or commercial heat pump
is that the latter can reverse its system. The heat pump
is one of the most modern means of heating and
cooling. Using no fuel, the electric heat pump
automatically heats or cools as determined by outside
temperature. The air type of unit works on the principle
of removing heat from the atmosphere. No matter how
cold the weather, some heat can always be extracted
and pumped indoors to provide warmth. To cool
during the hot months, this cycle is merely reversed
with the unit removing heat from the area to be cooled
and exhausting it to the outside air. The heat pump is
designed to control the moisture in the air and to
remove dust and pollen. Cool air, provided during hot
weather, enters the area with uncomfortable moisture
In winter, when a natural atmosphere is
desirable, air is not dried out when pumped indoors.
The heat pump is simple in operation (fig. 7-10).
In summer, the evaporator is cooling and the condenser
outside is giving off heat the evaporator picked up. In