E
Commissioning
(i)
Airflow Resistance
Airflow resistance refers to pressure drop caused by the economizer kit. Before installation, it is recommended to check
the pressure drop table which is provided in Engineering Data Book in order to do a correct design selection.
(ii)
Performance Adjustment
Performance of the unit will derate when the unit operates with fresh air mode, it depends on user's selection. Before
installation, it is recommended to check the correction factor table which is provided in Engineering Data Book in
order to do a correct design selection.
(iii) Mode Selection
Generally, the kit provides two mode selection, which are Economizer Mode and Fresh Air Mode.
- Economizer Mode: Provide 'free' cooling when the outdoor air temperature is suitable. It can used alone or in
conjunction with mechanical cooling.
- Fresh Air Mode: Provide minimum fresh air that is necessary for ventilation or local requirements.
Refer to hardware setting guideline provided in part (D) (v) under chapter "CONTROL OPERATION GUIDE" in this
manual for mode selection.
(iv) Minimum Fresh Air Selection
The kit provides minimum fresh air selection from 0~25% for both cool and heat mode. While the economizer mode
& fan mode can provide up to maximum 85% of fresh air.
Refer to hardware setting guideline provided in part (D) (v) under chapter "CONTROL OPERATION GUIDE" in this
manual for minimum fresh air selection.
(v)
Overcooled Protection Feature
Thermal discomfort may happen during the cold ambient due to the outdoor air damper opening. This situation
can be avoided when the overcooled protection feature is activated.
Refer to hardware setting guideline provided in part (D) (v) under chapter "CONTROL OPERATION GUIDE" in this
manual for the activation of overcooled protection setting.
(vi) Operating Range
The applicable operating range for unit with economizer feature same like normal unit. Refer to chapter "OPERATING
RANGE" in this manual.
However, the restriction of fresh air opening will occur in high ambient or low ambient in order to ensure the reliability
of the unit. Refer to Engineering Data Book for detail information.
The performance will be reduced at high ambient or low ambient, refer item (E)(ii).
(vii) Optional Air Filter
There is a 2" filter slot inside the unit. Optional filter (field supplied) is recommended as the second layer filtration
since outdoor air damper opening may bring in dust and dirt.
Service And Maintenance
F
(i)
Service of the filter
Airflow resistance may increase when the filter becomes dirty. Thus, clean the filter regularly with at least once
every 2 weeks. Air filter in rain hood which is exposed to outdoor environment may have chance to be damaged by
vermins or animals. Replace the air filter when it is damaged.
(ii)
Service of the indoor compartment
Outdoor air damper opening may still bring in dust and dirt as hood filter cannot fully filter the dirt particles. Thus,
indoor compartment must be cleaned as well during the service of filter.
(iii) Service of the damper
Wipe the dirty damper, especially outdoor air damper which is exposed to the environment all the time.
Refer to chapter "SERVICE AND MAINTENANCE" in this manual.
42
CAUTION