9
4 Maintenance
4.1 Standard Air Filter
The DHV-150H is equipped with a pleated cloth air
filter. This filter should be checked semi-annually.
Operating the unit with a dirty filter will reduce
dehumidifier capacity and efficiency and may cause
the compressor to cycle off and on unnecessarily on
the defrost control.
To access the air filter, remove the filter access panel
from the end of the DHV-150H by unscrewing the two
thumbscrews and sliding the panel to the left until it is
free from underneath the side panel. The filter(s)
should be readily visible and can be removed by
pulling them straight out of the DHV-150H.
The pleated cloth filter can generally be vacuumed
clean several times before needing replacement.
Replacement filters can be ordered from the factory or
purchased locally if available.
DO NOT
operate the
unit without the standard filter or with a less effective
filter than the standard filter. The heat exchange coils
inside the unit could become clogged and require
disassembly to clean.
4.2 High Efficiency Air Filter
An optional high efficiency pleated microglass paper
filter is available for the DHV-150H. This filter is rated
as 90%-95% efficient by the ASHRAE Dust Spot test
method 52-76. The high efficiency pleated microglass
paper filter should be used in conjunction with the
standard filter, and placed directly behind the standard
filter.
This filter is able to remove allergy-causing particles
from the airstream. Check the high efficiency air filter
every two years and replace if necessary. The high
efficiency filter has a much larger surface area than
the standard filter, thus the standard filter may need to
be cleaned or replaced several times before the high
efficiency filter requires replacement. Be careful not to
damage the fabric media when handling the high
efficiency pleated paper filter. Do not attempt to clean
the high efficiency pleated paper filter. It should be
replaced when it becomes restrictive (See Figure 7).
4.3 Optional Fresh Air Return
Check and clean the screen on the outdoor fresh air
return seasonally. The screen may become plugged
during the seasons when there are many particles in
the outdoor air.
5 Service
CAUTION
: Servicing the DHV-150H with its
high
pressure
refrigerant system and
high voltage
circuitry presents a health hazard which could result
in
death
, serious bodily
injury
, and/or property
damage
. Only qualified service people should
service this unit.
5.1 Warranty Notice
Warranty terms are provided at the end of this manual.
Please read the terms before any repair is initiated. If
a warranty repair is required, call the factory first at 1-
800-255-7749 for warranty claim authorization and
technical assistance.
5.2 Technical Description
The DHV-150H uses a refrigeration system similar to
an air conditioner's to remove heat and moisture from
incoming air, and add heat to the air that is discharged
(See Figure 3).
Figure 3: Refrigeration System of DHV-150H
Hot, high-pressure refrigerant gas is routed from the
compressor to the condenser coil (See Figure 3). The
refrigerant is cooled and condensed by giving up its
heat to the air that is about to be discharged from the
unit. The refrigerant liquid then passes through a
filter/drier and capillary tubing, which causes the
refrigerant pressure and temperature to drop. It next
enters the evaporator coil where it absorbs heat from
the incoming air and evaporates. The evaporator
operates in a flooded condition, which means that all
the evaporator tubes contain liquid refrigerant during
normal operation. A flooded evaporator should
