Form I-XE/CRGB/RPB, Page 38
35C. Optional Dirty Filter Switch - All Models
The optional dirty filter pressure switch is used to provide warning to
the user by energizing an indicator light on an optional remote console.
The light indicates that the filters are in need of cleaning or changing. The
adjustable, single-pole/normally open differential switch closes when
an increase in pressure differential above the setpoint, is sensed across
the filter bank.
This switch is located in the furnace section. See
FIGURE 19
, Item 17.
After the unit is started, before continuous operation, the dirty filter
switch must be set.
Instructions for Setting Dirty Filter Switch
With clean filters in place, blower doors closed, and blower in operation,
decrease the pressure setting by adjusting the set screw on the switch
clockwise until the filter light is energized or the screw is bottomed out.
At that point, adjust the set screw three full turns counterclockwise or
until the screw is top-ended. At that setpoint the filter light will be
activated at approximately 50% filter blockage.
FIGURE 44 - Dirty Filter Switch
Set screw (on front of switch)
must be manually adjusted after
the system is in operation.
Negative pressure connection is toward the "back or
bottom" of the switch
(senses blower side of filters)
Positive pressure connec-
tion is toward the "front or
top" of the switch
(senses air
inlet side of filters)
36. Optional Cooling Coil Cabinet,
Option AU (Outdoor Models)
The optional cooling coil cabinet is shipped separately for attachment
in the field. The cabinet accommodates either a chilled water or a refrig-
FIGURE 45 -
Optional Cooling
Coil Cabinet
35. Optional Filter Rack and Filters (cont'd)
35B. Filter Rack and Filters - Outdoor Models (cont'd)
FIGURE 43 - Filter
Arrangements - Outdoor
Models
A
B
C
D
E
Sizes 75-125
D
25 (635mm)
20
(508mm)
Sizes 150-175
A
A
C
C
25 (635mm)
20
(508mm)
Sizes 200-225
A
B
C
D
25 (635mm)
20
(508mm)
Sizes 250-300
B
D
D
E
25 (635mm)
20
(508mm)
20
(508mm)
25 (635mm)
Size 350
D
D
D
C
C
Size 400
25 (635mm)
20
(508mm)
B
D
Key:
Filter Code
Filter Size
A
16 x 20
B
20 x 20
C
16 x 25
D
20 x 25
E
25 x 25
Shaded areas are filter
blockoff plates
Average Efficiency and Arrestance by Filter Type (applies to
both indoor and outdoor models)
Type of Filter
Average Efficiency Average Arrestance
Disposable 1"
Less than 20%
75%
2"
Less than 20%
80%
Permanent 1"
Less than 20%
53% to 60%
2"
Less than 20%
64% to 67%
Pleated
1"
30% to 35%
90% to 93%
Disposable 2"
30% to 35%
90% to 93%
erant (DX) air conditioning coil. Cabinets alone have horizontal dis-
charge but may have an attached downturn plenum for vertical dis-
charge. Cooling coil cabinet dimensions are on page 6.
Cooling coil cabinets are lifted separately and attached to the heating/
makeup air system on the roof.
WARNINGS: Do not attach the cooling coil cabinet
before lifting the packaged blower/furnace system
into position. Lift cooling coil cabinet separately.
Do not attach the cooling coil cabinet while the
furnace is in operation.
Using the parts shipped inside the cooling coil cabinet, follow the in-
structions below to connect the coil cabinet to the furnace.
Installation Instructions
- In addition to normally required tools, a
driver extension, a hammer, and bar or short length of 2x4 will be re-
quired. Silicone caulking must be field-supplied.
1. After
the blower/furnace packaged system is in place on the roof curb
or mounting rails, use a 9/16" wrench or socket to remove the lifting
lugs that are on the discharge end of the system.
2.
Lift the cooling coil cabinet and position it with the inlet side next to
the discharge opening of the furnace. Remove the lifting lugs that are
on the cooling coil cabinet.
3.
Slide the cooling coil cabinet so that the duct flanges of the furnace
and the cooling coil cabinet butt together
(See FIGURE 46A)
.
4. Join the Duct Flanges
a) Use the four "U" shaped duct connector pieces and the 3/4"
screws to join the duct flanges. Attach one of the 19-1/2"
(495mm) long side connectors to both the top and bottom duct
connectors, being sure that the "U" in the metal is open to the
inside.
