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• Helmet must be worn to protect your head from falling objects.
Especially, when you work under an inspection opening, helmet must be worn to protect your head from
falling objects from the opening.
The manufacturer shall not assume any liability for the damage caused by not observing the description
of following.
Observe the following conditions when using the Heat recovery
ventilation unit
Installation requirements
:
Temperature range −15°C to +50°C, relative humidity 80% or less
Outdoor air conditions
:
Temperature range −20°C to +52°C, relative humidity 80% or less
Return air conditions
:
Temperature range +5°C to +40°C, relative humidity 80% or less
• If Heat recovery ventilation unit is used under conditions in which air after heat exchange is saturated,
condensation or frosts occur in the heat exchange element.
When such condition is expected, use the heater by heating air at the low temp side.
(For the detail, refer to "Dewing and frosting")
• Do not install the Heat recovery ventilation unit in a place where flames can come into contact with the unit.
If the Heat recovery ventilation unit is used for a long time without observing the conditions above,
deterioration or deformation of resin parts will occur and a malfunction may result.
Do not use the Heat recovery ventilation unit in location such as
kitchen, bathroom, swimming pool or air conditioning
cultivation room etc.
• Use of it in the location where large amount of soot are present leads to the clogging in the filter or in the heat
exchanger element, cause not to function properly.
• Use of it in the location where high humidity is present can cause condensation water drops from the inside
of the unit.
Dewing and frosting
• In cold regions, the surface (or inside) of the unit or the duct connector may be affected by condensation or
frosting depending on the outdoor air conditions or temperature / humidity of the ceiling cavity even though
the conditions for use are observed. In this case, add a heat insulator.
• Do not install the unit in a place where there is something that must not become wet. Depending on the
temperature or humidity of outdoor air and the installation place, water droplets may fall from the unit.
• As shown in the figure to the below, suppose a high temp absorbing air condition A and a low temp absorbing
air condition B are plotted on the air line figure, then a high temp air A is heat-exchanged by the unit and goes
out of the saturation curve as shown by Point C. In this case, the unit will be dewed or frosted. To avoid this,
heating a low temp air B up to B' is required so as to get C' below the saturation curve, before using the unit.
A
C
C'
B
B'
Dry-bulb temperature (°C)
17-EN
– 9 –
• Calculation example from Psychrometric chart
When the temperature exchange efficiency is 73.5% and the enthalpy efficiency is 60.5%
Example 1
In the following conditions, since the air after heat exchange is not saturated, condensation will not occur in the
heat exchange element.
Suction air at the high temp side
Suction air at the low temp side
Air after heat exchange
Example 2
In the following conditions, since the air after heat exchange is saturated and dew condensation occurs in the
heat exchanger element, use heater by heating the air from point B to point B'. (Humidity of point C' should be
less than 90% as a guide.)
Suction air at the high temp side
Suction air at the low temp side
Air after heat exchange
Suction air at the high temp side
Suction air at the low temp side
Air after heat exchange
• Our Heat recovery ventilation unit has been tested under condensation test condition described in JIS B 8628,
"Air-to-air heat and energy exchanger and ventilators" and found that condensation water does not drop.
Due to changes in temperature and humidity, dew condensation occurs even under similar conditions, may
cause condensation water to drop from the inside of the unit.
• Be sure to cover two ducts (OA, EA) at the outdoor side with heat insulators (Material: Glass Wool, Thickness-
25 mm or more) to prevent condensation and slope them downward to the outdoor side. (For its detail, refer
to "5. Installation
Duct installation")
• When the inside of the room is cooled by another air conditioner during the summer season and the
surrounding of the Heat recovery ventilation unit is expected to become high temperature and high humidity,
covering also two ducts at the indoor side with the heat insulators to prevent condensation is recommended.
• If the unit sucks high moisture air such as fog (relative humidity of 80% or more), condensation water may
drop from the unit. Do not operate the Heat recovery ventilation unit temporarily while high moisture air is
present.
* When such a condition is expected, avoid setting the 24-hour ventilation and the nighttime heat purge.
• Use of Heat recovery ventilation unit in bypass mode in winter may cause condensation on the inside of the
product or its discharge port.
* When such a condition is expected, use it in heat exchange mode.
• In cold areas where the wind is strong, due to the outside air sometimes entering while the Heat recovery
ventilation unit stops, use of the unit in combination with an intermediate mounting type electric shutter is
recommended.
• Do not install the unit near the water heater.
Dry-bulb temp
Wet-bulb temp
[°CDB]
[°CWB]
A
35
29
B'
20
17
C'
24
22.5
Dry-bulb temp
Wet-bulb temp
[°CDB]
[°CWB]
A
35
31.8
B
18
14
C
22.5
(22.5)
Dry-bulb temp
Wet-bulb temp
[°CDB]
[°CWB]
A
35
31.8
B'
22.1
17.7
C'
25.6
24.3
Humidity
[%]
64.3
60.9
77.1
Humidity
[%]
80
65
100
Humidity
[%]
80
65
89.7
18-EN
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