Asco 4820, User Manual, Page: 19 / 51

Installation
ASCO Model K875A Outdoor Load Bank
3-6
a. If the exhaust hoods are not used, the Load Banks are designed to tolerate up to 0.12"
water gage additional system airflow resistance. This includes air intake resistance
and resistance due to exhaust duct/louvers/screen. The exhaust must be screened to
keep debris from entering unit. The screen must be a minimum 75% open area
and/or exceed Load Bank duct area by a minimum of 50%.
b. If exhaust duct exits through motorized louvers, the design must be interlocked to
assure full open prior to operation. Consideration must also be given for louver
design and actuator to prevent heat problems.
c. Each fan/blower is designed to move 20,000 CFM per resistor stack. The entire unit
then moves (20,000 CFM times number of stacks).
Consult the factory if hoods are not used or if strong prevailing winds exist. Failure to obtain
written factory approval for special intake or exhaust conditions voids warranty.
ADDITIONAL AIRFLOW CONSIDERATIONS
1.
Load Banks mounted into a channel, trough, hollow, well, pit, surrounded completely by a
parapet wall or backed into a full corner require special considerations even if the other
conditions are met. In these cases, provide detailed site layout drawings to ASCO for
inspection and comments.
2.
Locations which have full or partial perimeter fence necessitate a review. The fencing
material should have at least 75% open area. The minimum clearances still apply. Overhead
fencing or grating is not recommended.
3.
Do not install Load Banks or other air handling devices within the same area. Any high
velocity air stream near the Load Bank air flow can disrupt the cooling. This is critical if the
other equipment is a source of heat. Any thermal rise on Load Bank intake air can create a
potential hazard.
4.
The Load Bank cooling system cannot be used for any purpose other than cooling the Load
Bank.
5.
In northern climates with snow depths exceeding 6 inches or blowing and drifting snow, a
physical inspection of the Load Bank intake and exhaust is required prior to operation. Any
significant snow drifts or snow depths must be cleared prior to operation.
6. Standard Load Banks are designed for operation between sea level and 2,000 feet maximum
altitudes. Operation at altitudes over 2,000 feet above sea level requires special
consideration. As the altitude increases, the effective cooling air diminishes. Contact ASCO
for assistance.