5703827-XIM-A-0319
Johnson Controls Ducted Systems
27
Blower phasing
ZM units are properly phased at the factory. Check for proper blower rotation. If the blower rotates in the wrong direction at start-up,
the electrical connection to the unit is misphased. Change the phasing of the
field line connection at the field supplied
disconnect
to obtain proper rotation.
Blower rotation
Check for the proper supply air blower rotation. If the blower is rotating backwards, the line voltage at the unit point of power
connection is misphased. See the “Blower phasing” section on page 27.
Adjusting the belt tension
To adjust the belt tension complete the following steps.
1.
Loosen the six belts nuts at the top and bottom. See Figure 19
Note:
Never loosen the static nut at the top of the adjustment bolt.
2.
Turn the adjustment bolt.
3.
Use a belt tension checker to apply a perpendicular force to one belt at the midpoint of the span shown in Figure 19. A
deflection distance of 4 mm (5/32 in.) is obtained.
4.
To determine the deflection distance from normal position, use a straight edge from sheave to sheave as a reference line.
The recommended deflection force is as follows:
Tension new belts at the max. deflection force recommended for the belt section.
5.
Re-tighten the belt nuts.
CAUTION
When you install equipment in a facility with a 3-phase high-leg delta power
supply, you must take care to ensure that the high-leg conductor is not
attached to either of the two legs of the (single phase, direct drive) X13 or
ECM motors. Failure to do so can result in the motor acting erratically or
not running at all.
Check for the high leg conductor by checking voltage of each phase to
ground.
Example: A or L1 phase to ground, voltage reading is 120V. B or L2 phase
to ground, voltage reading is 195 to 208V. C or L3 phase to ground, voltage
reading is 120V. Therefore B or L2 phase is the high Leg. The high should
always be wired to the center or B or L2 tap.
Note:
Check all three phase motors and compressors for proper rotation
after making a change. If it is necessary to change 3 phase motor rotation,
swap A or L1 and C or L3 only.
Table 16: Rated airflow - imperial units
Model
CFM
ESP (iwg)
ZM10
4000
0.3
ZM12
4700
0.35
Table 17: Rated airflow - metric units
Model
m
3
/s
ESP (Pa)
ZM10
1.89
75.0
ZM12
2.22
87.0
