JOHNSON CONTROLS
10
FORM 145.26-IOM1 (908)
11. INSTALLINg DUCT WORK
Install all duct-work to meet current
standard:
• ASHRAE/NFPA 90, Standard for Installation of
Warm air Heating and air Systems.
• State, provincial, and local codes Failure to follow
these standards could reduce air flow or increase
air leakage, resulting in reduced system perfor-
mance or equipment damage. Properly size duct
work based on heat loss and heat gain calcula-
tions. Doing so assures:
• Good heating and cooling installations;
• Delivery of required circulating air.
Design duct systems within the maximum external
static pressure limits indicated in Table 1.
0.1
0.2
0.3
0.4
0.5
0.6
0.7
HIgH
560
530
500
460
415
355
295
MED-HI
450
425
400
370
335
300
-
MED-LO
365
350
330
310
270
-
-
LOW
315
290
275
-
-
-
-
HIgH
705
375
635
585
535
470
405
MEDIUM
650
620
585
540
485
425
-
LOW
520
510
490
465
430
-
-
HIgH
920
880
840
800
750
700
640
MEDIUM
775
760
735
705
665
625
-
LOW
580
565
550
530
-
-
-
HIgH
1060
1020
980
935
885
830
770
MEDIUM
840
825
810
790
765
730
-
LOW
735
725
715
700
-
-
-
SWaC02412
SWaC03012
SWaC01212
EXTERNAL STATIC PRESSURE (in. wg.)
SWaC01812
UNIT MODEL
SPEED TAP
LD13530
TABLE 1 -
SWaC FaN PERFORMaNCE
SUPPLY AIR DUCT WORK
Duct attaching hardware must only be used on the
supply air outlet flanges. Refrigeration tubing is located
under the top panel near these flanges. Do not drill or
use screws in this area.
Supply air duct (plenum) connection
must be at least the same size as the
furnace supply air opening. Seal supply
air duct work to furnace casing, walls,
ceilings or floors.
RETURN AIR DUCT WORK & FILTERS
All return air entering the unit must be filtered. Refer to
Section 15 for filter size and instructions on installing the
filter rack. The return air filter must be supplied by the
installing contractor. The return duct should be sealed
to the unit casing and terminate outside the space con-
taining the furnace.
