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52
McQuay IM 987
Mechanical Installation
Mechanical Installation
Preparing Unit for Operation
Figure 61: RAH Spring Mount Hold Down Fasteners
Spring Isolated Fans
Releasing Spring Mounts
The optional spring-mounted supply and return fans are locked
down for shipment. Hold-down fasteners are located at each
spring mount. Remove these fasteners before operating the
fans.
Figure 64
shows a typical spring mount. Note that the
3/8" hold-down bolt securing the fan base to the unit cross
channel must be removed.
After removing the hold-down fasteners, rock the fan assembly
by hand to check for freedom of movement.
Figure 62: Spring Mounted Hold-down Fasteners, All Units
Figure 63: Fan Spring Mount Adjustment
* Grossly out-of-adjustment thrust restraints can affect this
dimension. Recheck after thrust restraints are adjusted.
Adjusting Spring Mounts
To change spring compression:
Loosen the 5/8-18 UNF hex nut.
Place some additional weight on the fan sled frame (use a lever
to slightly compress the spring/or raise the sled) to allow the
bolt to turn freely.
Place one or two drops of oil on the threads if needed. Use a
wide, flat-blade, socket drive bit with a recommended 1/2”
drive handle. Ensure that as the slotted bolt is turned, the
upper-rebound plate also turns. This action allows the bolt to
compress/decompress the compression plate, while having the
same affect on the spring. If the spring is compressed too
much, lift the sled before turning. If the spring is not
compressed enough, place weight on the sled corner to force it
down before turning.
Re-adjust the position of the lower-rebound plate so that the
sled has at least 3/4” travel and no more than 1-1/4” travel.
Figure 64: Spring Mount
WARNING
Moving machinery hazard. Can cause severe injury or death.
Before servicing equipment, disconnect power and lock off.
More than one disconnect may be required to de-energize unit.
Hold-down
fasteners
Hold-down
fasteners
This bracket is added,
and these 3/8" tie downs
are used for RDS 800C.
This bracket is added,
and these 3/8" tie downs
are used for RDS 800C.
3 /8 " ± 1 /4 "
with fan running
Leveling
screw
Spring
mount
assembly
Cross
channel
Jam nut
Fan base