5285473-UIM-E-1217
Johnson Controls Unitary Products
21
EXTERNAL STATIC PRESSURE SETUP
To measure external static pressure:
• Measure the supply air static pressure
• Record this positive number
• Measure the return air static pressure
• Record this negative number
• Treat the negative number as a positive and add the two numbers
together
• This is total system static
SECTION VII: MAINTENANCE
NORMAL MAINTENANCE
Periodic maintenance consists of changing or cleaning filters and gen-
eral cleaning of the outdoor coil.
FILTERS -
Inspect once a month. Replace Disposable or clean Perma-
nent Type as necessary. DO NOT replace Permanent Type with Dis-
posable.
MOTORS -
Indoor and outdoor fan motors are permanently lubricated
and require no maintenance.
OUTDOOR COIL -
Dirt should not be allowed to accumulate on the out-
door coil surface or other parts in the air circuit. Cleaning should be as
often as necessary to keep the coil clean. If water is used to clean the
coil, be sure that the power to the unit is shut off prior to cleaning.
TROUBLESHOOTING
FIGURE 12:
Measuring External Static Pressure
i-0w1035
$
5(7851$,5
'8&7
6833/<$,5
'8&7
0$;35(6685(36,*
,1&+(62):$7(5
i)*w1035
WARNING
Prior to any of the following maintenance procedures, shut off all
power to the unit, to avoid personal injury.
NOTICE
DO NOT use a pressure washer as coil fin damage will occur.
CAUTION
Exercise care when cleaning the coil so that the coil fins are not dam-
aged.
Do not permit the hot outdoor air discharge to be obstructed by over-
hanging structures or shrubs.
!
!
WARNING
Troubleshooting of components necessarily requires opening the
electrical control box with the power connected to the unit. Use
extreme care when working with live circuit! Check the unit name-
plate for the correct range before making any connections with line
terminals.
CAUTION
The wire number or color and terminal designations referred to may
vary. Check the wiring label inside the control box access panel for
the correct wiring.
!
!
