Therma-Stor Products Group UA-150H - Manual (Page 15)

6. Maintenance
6.1 Standard Air Filter
The UA-150H is equipped with a pleated cloth air filter. This filter
should be checked every three months. 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 UA-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 UA-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.
6.2 High Efficiency Air Filter
An optional high efficiency pleated microglass paper filter is
available for the UA-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).
6.3 Impeller Fan Oiling
The impeller fan motor is factory lubricated for many years of normal
operation, and no further oiling is required.
6.4 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.
7. Service
7.1 Warranty
A warranty certificate has been enclosed with this unit; read it
before any repair is initiated. If a warranty repair is required, call the
factory first at 1-800-533-7533 for warranty claim authorization and
technical assistance.
7.2 Technical Description
The UA-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 15).
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 maintain nearly constant pressure and
temperature across the entire coil, from inlet to outlet.
The mixture of gas and liquid refrigerant enter the accumulator
after leaving the evaporator coil. The accumulator prevents any
liquid refrigerant from reaching the compressor. The compressor
evacuates the cool refrigerant gas from the accumulator and
compresses it to a high pressure and temperature to repeat the
process.
FOR HVAC INSTALLER ONLY
15 Ultra-Aire 150H Installer’s & Owner’s Manual
Figure 15: Refrigeration System of UA-150H