Bryant 549B User Manual
installation, start-up and
service instructions
SINGLE PACKAGE ROOFTOP
HIGH-EFFICIENCY HEAT PUMP UNITS
Cancels: II 549B-90-5 II 549B-90-6
Dura
Pac
Plus Series
Sizes 090-120
71/2 to 10 Tons
549B
10/15/05
IMPORTANT — READ BEFORE INSTALLING
Read and become familiar with these installation instructions before installing this unit.
Be sure the ins tallation conforms to al l applicab le local an d
national codes.
These instructions contain important information for the
proper maintenance and repair of this equipment. Retain
these instructions for future use.
CONTENTS
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 1
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-33
I. Step 1 — Provide Unit Support. . . . . . . . . . . . . . . . . 1
II. Step 2 — Field Fabricate Ductwork . . . . . . . . . . . . . 1
III. Step 3 — Install Condensate Drain Line and
External Trap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
IV. Step 4 — Rig and Place Unit . . . . . . . . . . . . . . . . . . . 3
V. Step 5 — Make Electrical Connections . . . . . . . . . . 6
VI. Step 6 — Adjust Factory-Installed Options. . . . . . 10
VII. Step 7 — Adjust Indoor-Fan Speed . . . . . . . . . . . . 19
PRE-START-UP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34-36
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36-39
TROUBLESHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . . . .40-42
INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
START-UP CHECKLIST . . . . . . . . . . . . . . . . . . . . . . . . . . CL-1
SAFETY CONSIDERATIONS
Installation and servicing air-conditioning equipment can be
hazardous due to system pressure and electrical components. Only trained and qualified service personnel should
install, repair, or servic e air-conditioning equipment.
Untrained personnel can perform basic maintenance functions of cleaning coils and filters and replacing filters. All
other operations should be performed by trained service personnel. When working on air-conditioning equipment, observe
precautions in the literature, tags and labels attached to the
unit, and other safety precautions that may apply.
Follow all safety codes. Wear safety glasses and work gloves.
Use quenching cloth for unbrazing operations. Have fire
extinguishers available for all brazing operations.
WARNING: Before performing service or maintenance operations on unit, turn off main power switch
to unit and install lockout tag on disconnect. Electrical
shock could cause personal injury.
CAUTION: Ensure voltage listed on unit data
plate agrees with electrical supply provided for the
unit.
INSTALLATION
This unit is shipped in the vertical configuration. To convert
to horizontal configuration, remove the side duct opening
covers. Using the same screw s, install th e cover s on th e vertical duct openings with the insulation-side down. Seals
around duct openings must be tight.
I. STEP 1 — PROVIDE UNIT SUPPORT
A. Roof Curb
Assemble and install the accessory roof curb in acco rdance
with instructions shipped wi th the curb. See Fig. 1. Install
insulation, cant stri ps, roofing felt, and counter flashing as
shown. Ductwork must be attached to the curb. If electric control power will be routed through the basepan, use the
appropriate accessory kit listed in Fig. 1, available from your
local distributor. Attach the accessory thru-the-bottom service connections to the basepan in accordance with the accessory installa tion inst ruct ions. Conn ect ions m ust b e in stal led
before the unit is set on the roof curb.
IMPORTANT: The gasketing of the unit to the roof curb is
critical for a watertight seal. Install the gasket supplied with
the roof curb as shown i n Fig. 1. An imprope rly applie d gasket can also result in air leaks and poor unit performance.
The roof curb should be level. Unit leveling tolerances are
shown in Fig. 2. This is necessary for the unit drain to function properly. Refer to Accessory Roof Curb Installation
Instructions for additional information as required.
B. Slab Mount (Horizontal Units Only)
Provide a level concrete slab that ex te nds a m ini mum o f 6 i n.
beyond the unit cabinet. Install a gravel apron in front of the
condenser coil air inlet to prevent grass and foliage from
obstructing airflow.
NOTE: Horizontal units may be installed on a roof curb if
required.
C. Alternate Unit Support (Curb or Slab Mount)
A non-combustible sleeper ra il can be used in the unit curb
support area. If sleeper rails cannot be used, support the
long sides of the unit with a minimum of 3 equally spaced
4-in. x 4-in. pads on each side.
II. STEP 2 — FIELD FABRICATE DUCTWORK
On vertical discharge units, secure all duc ts to the roof cu rb
and building structure. Do not connect ductwork to the unit.
For horizontal applications, field-supplied flanges should be
attached to horizontal discharge openi ngs and all ductwork
attached to the flanges. Insulate and weatherproof all e xternal ductwork, joints, and roof openings with counter flashing
and mastic in accordance with applicable codes.
Ducts passing through a n unco nditi one d spa ce mu st be ins ulated and covered with a vapor barrier.
If a plenum return is used on a vertical unit, the return
should be ducted through the roof deck to comply w ith applicable fire codes.
A minimum clearance to combustibles is not required around
ductwork on vertical discharge units. On horizontal discharge units, a minim um c learanc e of 1 in. is re quired for the
first 12 in. of ductwork. Cabinet return-air static pressure (a
negative condition) shall not exceed 0.30 in. wg with economizer or 0.45 in. wg without economize r.
CONNECTOR PKG.
ACCY.
CRBTMPWR001A01
CRBTMPWR002A01 1
CRBTMPWR003A01
CRBTMPWR004A01
B C D ALT DRAIN HOLE GAS POWER CONTROL ACCESSORY POWER
3
2′-8
7
[827]
/16″
1′-1015/16″
[583]
13/4″
[44.5]
ROOF CURB
ACCESSORY
CRRFCURB003A01 1′-2″ [356]
CRRFCURB004A01 2′-0″ [610]
/4″ [19] NPT
1
/2″ [12.7] NPT3/4″ [19] NPT
3
/4″ [19] NPT 11/4″ [31.7]
“A”
UNIT
SIZE
549B
090-120
3
/4″ [19] NPT
1
/4″ [31.7]
1
/2″ NPT
[12.7]
1
/2″ NPT
[12.7]
NOTES:
1. Roof curb accessory is shipped disassembled.
2. Insulated panels: 1-in. thick polyurethane foam, 1
density.
3. Dimensions in [ ] are in millimeters.
4. Roof curb: 16-gage steel.
5. Attach ductwork to curb (flanges of duct rest on curb).
6. Service clearance 4 ft on each side.
1
/2″ NPT
[12.7]
7. Direction of airflow.
8. Connector packages CRBTMPWR001A01 and 2A01
are for thru-the-curb gas type. Packages
CRBTMPWR003A01 and 4A01 are for thru-the-bottom
type gas connections.
3
/4 lb
Fig. 1 — Roof Curb Details
—2—
MAXIMUM ALLOWABLE
DIFFERENCE (in.)
A-B B-C A-C
0.5 1.0 1.0
Fig. 2 — Unit Leveling Tolerances
III. STEP 3 — INSTALL CONDENSATE DRAIN LINE AND
EXTERNAL TRAP
Condensate drain connections are located on the botto m and
end of the unit. Unit discharge connections do not determine
the use of drain connections; either drain connection can be
used with vertical or horizontal applications.
When using the standard end drain connection, make sure
the red plug in the alternate bottom connection is tight
before installing the unit.
To use the bottom drain connection for a roof curb installation, relocate the factory-installed red plug from the bottom
connection to the end c onnectio n. The ce nter drai n plug looks
like a star connection, but can be removed with a
1
/2-in.
socket drive exten sion. See Fig. 3A. The pipin g for the condensate dr ain and e xternal t rap can be completed after the
unit is in place.
All units must have an external trap for condensate drainage. Install a trap at least 4-in. deep and protect against
freeze-up. If a dra in line is installe d downstream from the
external trap, pitch the line away from the unit at 1 in. per
10 ft of run. Do not use a pipe size smaller than the unit
connection (
3
/4-in.). See Fig. 3B.
IV. STEP 4 — RIG AND PLACE UNIT
Inspect the unit for transportation dama ge. File any claim
with the transportation agency . Keep the unit upright and do
not drop it. Spreader bars are not required if top crating is
left on the unit. Rol lers may be used to move th e unit acro ss
a roof. Level by using the unit frame as a reference. See
Table 1 and Fig. 4 for additional information. Operating
weight is shown in Table 1 and Fig. 4.
Lifting holes are pr ovide d i n t he b ase rai ls as shown in Fig. 4
and 5. Refer to rigging instructions on the unit.
DRAIN OUTLET
NOTE: Drain plug is shown in factory-installed position.
DRAIN PLUGHORIZONTAL
Fig. 3A — Condensate Drain Connection (Side View)
NOTE: Trap should be deep enough to offset maximum unit static dif-
ference. A 4-in. trap is recommended.
Fig. 3B — Condensate Drain Piping Details
NOTES:
1. Dimension in ( ) is in millimeters.
2. Hook rigging shackles through holes in base rail, as shown in detail ‘‘A.’’
Holes in base rails are centered around the unit center of gravity. Use
wooden top skid when rigging to prevent rigging straps from damaging unit.
3. Unit weights do not include economizer. See Table 1 for unit weight of
economizer.
4. Unit weights do not include skid.
CAUTION: All panels must be in place when rigging.
Fig. 4 — Rigging Details
UNIT
549B
090 870 395 77.42 1966.5 41.5 1054 42.12 1070
102,120 1000 454 77.42 1966.5 41.5 1054 42.12 1070
WEIGHT
lb kg in. mm in. mm in. mm
‘‘A’’ ‘‘B’’ ‘‘C’’
UNIT
OPERATING
DIMENSIONS
—3—
A. Positioning
Maintain clearance around and above the unit to provide
proper airflow and service access. See Fig. 5.
Position the unit on the roof curb so that the f oll ow in g clea rances are maintained:
1
/4-in. clearance between the roof curb
and the base rails on each side and the duct side of unit;
5
3
/16-in. clearance between t he roof cu rb and con denser s ide
of unit (see Fig. 1, section C-C).
Table 1 — Physical Data
Do not install the unit indoors. Do not locate the unit air inlet
near exhaust vents or other sources of contaminated air.
Although the unit is weatherproof, guard against water from
higher level runoff and overhangs.
After the unit is in position, remove the polyethylene shipping wrapper and rigging skid.
BASE UNIT 549B 090 102 120
NOMINAL CAPACITY (tons) 7
OPERATING WEIGHT (lb)
Unit 870 1000 1000
EconoMi$er IV 75 75 75
Roof Curb 223 223 223
COMPRESSOR Scroll
Quantity 22 2
Oil (oz) (each compr) 57 70 57
REFRIGERANT TYPE R-22
Operating Charge (lb)
Circuit 1 9.5 11.0 10.7
Circuit 2 9.5 11.0 10.8
OUTDOOR FAN Propeller
Quantity...Diameter (in.) 2...22 2...22 2...22
Nominal Cfm 6500 6500 6500
Motor Hp...Rpm
OUTDOOR COIL Enhanced Copper Tubes, Aluminum Fins, Fixed Orifice Metering Device
Rows...Fins/in. 2...17 2...17 2...17
Total Face Area (sq ft) 20.5 25.1 25.1
INDOOR FAN Centrifugal Type
Quantity...Size (in.) Standard 1...15 x 15 1...15 x 15 1...15 x 15
Type Drive Standard Belt Belt Belt
Nominal Cfm 3000 3400 4000
Maximum Continuous Bhp Standard 2.90 2.90 3.70
Motor Frame Size Standard 56 56 56
Nominal Rpm Standard 1725 1725 1725
Fan Rpm Range Standard 730-950 840-1085 860-1080
Motor Bearing Type Ball Ball Ball
Maximum Allowable Rpm 2100 2100 2100
Motor Pulley Pitch Diameter Min/Max (in.) Standard 3.4/4.4 3.4/4.4 4.0/5.0
Nominal Motor Shaft Diameter (in.) Standard
Fan Pulley Pitch Diameter (in.) Standard 8.0 7.0 8.0
Belt, Quantity...Type...Length (in.) Standard 1...A...51 1...A...51 1...A...53
Pulley Center Line Distance (in.) Standard 16.75-19.25 16.75-19.25 15.85-17.50
Speed Change per Full Turn of
Movable Pulley Flange (rpm)
Movable Pulley Maximum Full
Turns from Closed Position
Factory Setting Standard 555
Factory Speed Setting (rpm) Standard 730 840 860
Fan Shaft Diameter at Pulley (in.) 111
High-Static 1...15 x 15 1...15 x 15 1...15 x 15
High-Static Belt Belt Belt
High-Static 4.20 4.20 5.25
High-Static 56 56 56
High-Static 1725 1725 1725
High-Static 860-1080 860-1080 830-1130
High-Static 4.0/5.0 4.0/5.0 2.8/3.8
High-Static
High-Static 8.0 8.0 5.8
High-Static 1...A...53 1...A...53 1...BX...48
High-Static 16.75-19.25 16.75-19.25 15.85-17.50
Standard 45 45 45
High-Static 45 45 60
Standard 555
High-Static 556
High-Static 555
High-Static 860 860 887
INDOOR COIL Enhanced Copper Tubes, Aluminum Double-Wavy Fins,
Rows...Fins/in. 3...15 4...15 4...15
Total Face Area (sq ft) 8.9 11.1 11.1
HIGH-PRESSURE SWITCH (psig)
Standard Compressor Internal Relief 625
Cutout 428
Reset (Auto.) 320
LOSS-OF-CHARGE/LOW-PRESSURE SWITCH (Liquid Line) (psig)
Cutout 7 ± 3
Reset (Auto.) 22 ± 5
FREEZE PROTECTION THERMOSTAT
Opens (F) 30
Closes (F) 45
1
/
1
/4...1100
7
/
8
7
/
8
2
81/
1
/4...1100
7
/
8
7
/
8
2
10
1
/4...1100
7
/
8
7
/
8
Acutrol Metering Device
OUTDOOR-AIR INLET SCREEN Cleanable. Screen size and quantity vary by option selected.
RETURN-AIR FILTERS Throwaway
Quantity...Size (in.) 4...16 x 20 x 2 4...20 x 20 x 2
LEGEND
Bhp — Brake Horsepower
—4—
Fig. 5 — Base Unit Dimensions
—5—
V. STEP 5 — MAKE ELECTRICAL CONNECTIONS
C
C
WARNING: Unit cabinet must have an uninter-
rupted, unbroken electrical ground to minimize the
possibility of personal injury if an electrical fault
should occur. This ground may consist of elec tric al wir e
connected to unit ground lug in control compartment,
or conduit approved for electrical ground when
installed in accordance with NEC (National Electrical
Code), ANSI/NFPA (American National Standards
Institute/National Fire Protection Association), latest
edition, and local electrical codes. Failure to follow this
warning could result in the installer being liable for
3. For units with electric heat, refer to Table 2 and
Accessory Installation Instructions.
NOTE: During operation, voltage to compressor terminals
must be within the range indicated on the unit nameplate
(see Tables 3A-3D). On 3-phase units, voltages between
phases must be balanced within 2%, and the current within
10%. Use the formula shown in Tables 3A-3D, Note 2 on
page 9 to determine the percentage of voltage imbalance.
Operation on imp rop er lin e volt age or exc essiv e pha se imba lance constitutes abuse and may cause damage to electrical
components. (Such operation would invalidate any applicable Bryant warranty .)
personal injury of others.
A. Field Power Supply
All units except 208/230-v units are factory wired for the
voltage shown on the nameplate. If the 208/230-v unit will be
connected to a 208-v power supply, the transformer must be
rewired by moving the black wire from the 230-v
1
/4-in. male
spade terminal on the transformer and c onnecting it to the
1
200-v
/4-in. male spade terminal on the transformer.
Refer to the unit label diagram for additional information.
Pigtails are provided for fie ld wire connectio ns. Use factorysupplied splices or a UL (Underwriters’ Laboratories)
approved copper/aluminum connector.
When installing units, provide a disconnect per NEC.
All field wiring must comply wi th the N E C and lo cal require-
ments. In Canada, electrical connections must be in accordance with CSA (Canadian Standards Association) C22.1
Canadian Electrical Code Part One.
Install field wiring as foll ows:
1. Install conduit through the side panel openings. For
units without electric heat, install conduit between
the disconnect and control box.
2. Install power lines to terminal connections as shown
LEGEND
— Contactor
OMP — Compressor
IFC — Indoor Fan Contactor
NEC — National Electrical Code
Field Wiring
Factory Wiring
Splice Connection
(Factory-Supplied)
Fig. 6 — Power Wiring Connections
208/230-3-60
460-3-60
in Fig. 6.
Table 2 — Electric Heating Capacities
UNIT
549B
090
102
120
*Two heater packages required to provide kW indicated.
NOTES:
1. The rated heater voltage is 240 and 480 v. If power distribution voltage varies
from rated heater voltage, heater kW will vary accordingly.
2. To determine heater kW at voltages other than those shown in table, use the
following formula:
Heater kW
2
voltage)
UNIT VOLTAGE
(60 Hz)
208/230/240
(3 phase)
460/480
(3 phase)
208/230/240
(3 phase)
460/480
(3 phase)
208/230/240
(3 phase)
460/480
(3 phase)
= Heater kW rated x (unit power distribution voltage/rated heater
new
ACCESSORY
kW
7.8/ 9.6/10.4
12.0/14.7/16.0
18.6/22.8/24.8
24.0/29.4/32.0
31.8/39.0/42.4*
12.8/13.9
15.2/16.5
25.6/27.8
30.4/33.0
38.4/41.7*
7.8/ 9.6/10.4
12.0/14.7/16.0
18.6/22.8/24.8
24.0/29.4/32.0
31.8/39.0/42.4*
12.8/13.9
15.2/16.5
25.6/27.8
30.4/33.0
38.4/41.7*
7.8/ 9.6/10.4
12.0/14.7/16.0
24.0/29.4/32.0
31.8/39.0/42.4*
37.6/46.2/50.0*
15.2/16.5
25.6/27.8
30.4/33.0
38.4/41.7*
46.2/50.0*
ELECTRIC HEATER PART NUMBER
CRHEATER---A00
017
010
011
012
012 and 017
016
013
014
015
014 and 016
117
110
111
112
112, 117
116
113
114
115
114,116
017
010
012
012 and 017
010 and 012
013
014
015
014 and 016
013 and 015
As an example:
For a 16 kW heater rated at 240 v with a power distribution voltage of 215 v
= 16 kW (215/240)
kW
new
kW
= 12.8 kW (rating at 215 v)
new
SINGLE POINT BOX PACKAGE NO.
CRSINGLE---A00
2
007
007
009
009
013
006
006
008
008
—
012
012
015
015
017
011
011
014
014
016
012
012
015
017
017
011
014
014
016
016
—6—
UNIT
549B
090
102
120
Table 3A — Electrical Data — Standard Motor Units Without Electrical Convenience Outlet
NOMINAL
VOLTAGE
(V-Ph-Hz)
208/230-3-60 187 254 12.4 88.0 1.4 7.5
460-3-60 414 508 6.4 44.0 0.7 3.4
208/230-3-60 187 254 13.9 105 1.4 7.5
460-3-60 414 508 7.9 55.0 0.7 3.4
208/230-3-60 187 254 19.3 123.0 1.4 10.6
460-3-60 414 508 10.0 62.0 0.7 4.8
VOLTAGE
RANGE
Min Max RLA LRA FLA FLA kW** FLA MCA MOCP FLA LRA
COMPRESSOR
(each)
OFM
(each)
IFM ELECTRIC HEAT* POWER SUPPLY
—
7.8/10.4
12.0/16.0
18.6/24.8
24.0/32.0
31.8/42.4
—
13.9
16.5
27.8
33.0
41.7
—
7.8/10.4
12.0/16.0
18.6/24.8
24.0/32.0
31.8/42.4
—
13.9
16.5
27.8
33.0
41.7
—
7.8/10.4
12.0/16.0
24.0/32.0
31.8/42.4
37.6/50.0
—
16.5
27.8
33.0
41.7
50.0
—
21.7/ 25.0
33.3/ 38.5
51.6/ 59.7
66.6/ 77.0
88.3/102.0
—
16.7
19.8
33.4
39.7
50.2
—
21.7/ 25.0
33.3/ 38.5
51.6/ 59.7
66.6/ 77.0
88.3/102.0
—
16.7
19.8
33.4
39.7
50.2
—
21.7/ 25.0
33.3/ 38.5
66.6/ 77.0
88.3/102.0
104.4/120.3
—
19.8
33.4
39.7
50.2
60.1
38.2/ 38.2
65.3/ 69.5
79.8/ 86.3
102.7/112.8
121.5/134.5
148.6/165.7
19.2
40.1
44.0
61.0
68.8
82.0
41.3/ 41.3
68.4/ 72.5
82.9/ 89.4
105.8/115.9
124.5/137.5
151.7/168.8
22.3
43.2
47.0
64.0
71.9
85.0
56.8/ 56.8
84.0/ 88.1
98.5/105.0
140.1/153.1
167.2/184.3
187.3/177.1
28.7
53.5
70.5
78.3
91.5
88.8
110/125
125/150
150/175
110/125
125/150
175/175
100/110
150/175
175/200
200/200
40/ 40††
70/ 70††
80/ 90
20††
45††
45††
70
70
90
45/ 45††
70/ 80††
90/ 90
25††
45††
50††
70
80
90
60/ 60††
90/ 90
30††
60††
80
80
100
100
MINIMUM UNIT
DISCONNECT
SIZE†
242/242
40/ 40
264/267
65/ 69
275/281***
79/ 85
20
39
43
59
66
78
43/ 43
68/ 72
82/ 88
23
43
46
62
69
81
60/ 60
85/ 89
98/104
30
53
69
76
88
99
294/302***
309/319***
330/344***
276/276
298/301
309/315***
328/336***
343/353***
364/378***
337/337
358/362***
370/375***
403/414***
425/439***
441/457***
100/109
117/129
142/158
103/112
120/132
145/161
136/148
161/177
180/198
121
138
141
155
161
171
143
160
163
177
183
193
170
189
203
209
220***
230***
Table 3B — Electrical Data — Standard Motor Units With Electrical Convenience Outlet
UNIT
549B
090
NOMINAL
VOLTAGE
(V-Ph-Hz)
208/230-3-60 187 254 12.4 88.0 1.4 7.5
460-3-60 414 508 6.4 44.0 0.7 3.4
208/230-3-60 187 254 13.9 105 1.4 7.5
102
460-3-60 414 508 7.9 55.0 0.7 3.4
208/230-3-60 187 254 19.3 123.0 1.4 10.6
120
460-3-60 414 508 10.0 62.0 0.7 4.8
NOTE: See legend and notes on page 9.
VOLTAGE
RANGE
Min Max RLA LRA FLA FLA kW** FLA MCA MOCP FLA LRA
COMPRESSOR
(each)
OFM
IFM ELECTRIC HEAT* POWER SUPPLY
(each)
—
7.8/10.4
12.0/16.0
18.6/24.8
24.0/32.0
31.8/42.4
—
13.9
16.5
27.8
33.0
41.7
—
7.8/10.4
12.0/16.0
18.6/24.8
24.0/32.0
31.8/42.4
—
13.9
16.5
27.8
33.0
41.7
—
7.8/10.4
12.0/16.0
24.0/32.0
31.8/42.4
37.6/50.0
—
16.5
27.8
33.0
41.7
50.0
—
21.7/ 25.0
33.3/ 38.5
51.6/ 59.7
66.6/ 77.0
88.3/102.0
—
16.7
19.8
33.4
39.7
50.2
—
21.7/ 25.0
33.3/ 38.5
51.6/ 59.7
66.6/ 77.0
88.3/102.0
—
16.7
19.8
33.4
39.7
50.2
—
21.7/ 25.0
33.3/ 38.5
66.6/ 77.0
88.3/102.0
104.4/120.3
—
19.8
33.4
39.7
50.2
60.1
43.0/ 43.0
70.1/ 74.3
84.6/ 91.1
107.5/117.6
126.3/139.3
153.4/170.5
46.1/ 46.1
73.2/ 77.3
87.7/ 94.2
110.6/120.7
129.3/142.3
156.5/173.6
61.6/ 61.6
88.8/ 92.9
103.3/109.8
144.9/157.9
172.0/189.1
192.1/181.9
21.4
42.3
46.1
63.1
71.0
84.1
24.5
45.3
49.2
66.2
74.1
87.2
30.9
55.6
72.6
80.5
93.6
91.0
45/ 45††
80/ 80
90/100
110/125
150/150
175/175
25††
45††
50††
70
80
90
50/ 50††
80/ 80
90/100
125/125
150/150
175/175
25††
50††
50††
70
80
90
70/ 70
90/100
110/110
150/175
175/200
200/200
35††
60††
80
90
100
100
MINIMUM UNIT
DISCONNECT
SIZE†
247/247
46/ 46
269/272
71/ 75
280/285***
84/ 90
23
42
46
61
68
80
49/ 49
74/ 78
87/ 93
26
45
49
64
72
84
65/ 65
90/ 94
33
55
71
78
90
102
298/307***
313/324***
335/349***
281/281
303/306
314/319***
332/341***
347/358***
369/383***
341/341
363/366***
375/380***
408/418***
430/443***
446/462***
105/115
122/134
147/163
108/118
126/138
151/166
104/110
142/154
167/183
185/204
123
140
143
157
163
174
145
162
165
179
185
196
172
191
205
211
222***
232***
—7—
Table 3C — Electrical Data — High-Static Motor Units Without
Electrical Convenience Outlet
UNIT
549B
090
102
120
NOMINAL
VOLTAGE
(V-Ph-Hz)
208/230-3-60 187 254 12.4 88.0 1.4 10.6
460-3-60 414 508 6.4 44.0 0.7 4.8
208/230-3-60 187 254 13.9 105 1.4 10.6
460-3-60 414 508 7.9 55.0 0.7 4.8
208/230-3-60 187 254 19.3 123.0 1.4 15.0
460-3-60 414 508 10.0 62.0 0.7 7.4
VOLTAGE
RANGE
Min Max RLA LRA FLA FLA kW** FLA MCA MOCP FLA LRA
COMPRESSOR
(each)
OFM
IFM ELECTRIC HEAT* POWER SUPPLY
(each)
—
7.8/10.4
12.0/16.0
18.6/24.8
24.0/32.0
31.8/42.4
—
13.9
16.5
27.8
33.0
41.7
—
7.8/10.4
12.0/16.0
18.6/24.8
24.0/32.0
31.8/42.4
—
13.9
16.5
27.8
33.0
41.7
—
7.8/10.4
12.0/16.0
24.0/32.0
31.8/42.4
37.5/50.0
—
16.5
27.8
33.0
41.7
50.0
—
21.7/ 25.0
33.3/ 38.5
51.6/ 59.7
66.6/ 77.0
88.3/102.0
—
16.7
19.8
33.4
39.7
50.2
—
21.7/ 25.0
33.3/ 38.5
51.6/ 59.7
66.6/ 77.0
88.3/102.0
—
16.7
19.8
33.4
39.7
50.2
—
21.7/ 25.0
33.3/ 38.5
66.6/ 77.0
88.3/102.0
104.4/120.3
—
19.8
33.4
39.7
50.2
60.1
41.3/ 41.3
68.4/ 72.6
82.9/ 89.4
105.8/115.9
124.6/137.6
151.7/168.8
20.6
41.5
45.4
62.4
70.2
83.4
44.4/ 44.4
71.5/ 75.6
86.0/ 92.5
108.9/119.0
127.6/140.6
154.8/171.9
23.7
44.6
48.4
65.4
73.3
86.4
61.2/ 61.2
88.4/ 92.5
102.9/109.4
144.5/157.5
171.6/188.7
191.7/181.5
31.3
56.1
73.1
80.9
94.1
96.4
45/ 45††
70/ 80
90/ 90
110/125
125/150
175/175
25††
45††
50††
70
80
90
45/ 45††
80/ 80
90/100
110/125
150/150
175/175
25††
45††
50††
70
80
90
70/ 70
90/100
110/110
150/175
175/200
200/200
35††
60††
80
90
100
100
MINIMUM UNIT
DISCONNECT
SIZE†
267/267
44/ 44
288/292
69/ 73
300/305***
82/ 88
22
41
45
60
68
80
47/ 47
72/ 76
85/ 91
25
44
48
63
71
83
65/ 65
90/ 94
33
56
72
79
91
102
318/336***
333/344***
355/369***
301/301
322/326
334/339***
352/360***
367/378***
389/403***
360/360
382/385***
393/399***
427/437***
448/462***
464/480***
103/113
121/132
145/169
106/116
124/136
149/164
103/109
141/153
166/182
185/203
134
150
153
167
173
184
156
172
175
189
195
206
181
201
215
221
231***
241***
Table 3D — Electrical Data — High-Static Motor Units With Electrical Convenience Outlet
UNIT
549B
090
NOMINAL
VOLTAGE
(V-Ph-Hz)
208/230-3-60 187 254 12.4 88.0 1.4 10.6
460-3-60 414 508 6.4 44.0 0.7 4.8
208/230-3-60 187 254 13.9 105 1.4 10.6
102
460-3-60 414 508 7.9 55.0 0.7 4.8
208/230-3-60 187 254 19.3 123.0 1.4 15.0
120
460-3-60 414 508 10.0 62.0 0.7 7.4
NOTE: See legend and notes on page 9.
VOLTAGE
RANGE
Min Max RLA LRA FLA FLA kW** FLA MCA MOCP FLA LRA
COMPRESSOR
(each)
OFM
IFM ELECTRIC HEAT* POWER SUPPLY
(each)
—
7.8/10.4
12.0/16.0
18.6/24.8
24.0/32.0
31.8/42.4
—
13.9
16.5
27.8
33.0
41.7
—
7.8/10.4
12.0/16.0
18.6/24.8
24.0/32.0
31.8/42.4
—
13.9
16.5
27.8
33.0
41.7
—
7.8/10.4
12.0/16.0
24.0/32.0
31.8/42.4
37.5/50.0
—
16.5
27.8
33.0
41.7
50.0
—
21.7/ 25.0
33.3/ 38.5
51.6/ 59.7
66.6/ 77.0
88.3/102.0
—
16.7
19.8
33.4
39.7
50.2
—
21.7/ 25.0
33.3/ 38.5
51.6/ 59.7
66.6/ 77.0
88.3/102.0
—
16.7
19.8
33.4
39.7
50.2
—
21.7/ 25.0
33.3/ 38.5
66.6/ 77.0
88.3/102.0
104.4/120.3
—
19.8
33.4
39.7
50.2
60.1
46.1/ 46.1
73.2/ 77.4
87.7/ 94.2
110.6/120.7
129.4/142.4
156.5/173.6
49.2/ 49.2
76.3/ 80.4
90.8/ 97.3
113.7/123.8
132.4/145.4
159.6/176.7
66.0/ 66.0
93.2/ 97.3
107.7/114.2
149.3/162.3
176.4/193.5
196.5/186.3
22.8
43.7
47.5
64.5
72.4
85.5
25.9
46.7
50.6
67.6
75.5
88.6
33.5
58.2
75.2
83.1
96.2
93.6
50/ 50††
80/ 80
90/100
125/125
150/150
175/175
25††
45††
50††
70
80
90
50/ 50††
80/ 90
100/100
125/125
150/150
175/200
30††
50††
60††
70
80
90
70/ 70
100/100
110/125
150/175
200/200
200/200
35††
60††
80
90
100
100
MINIMUM UNIT
DISCONNECT
SIZE†
271/271
49/ 49
293/296
74/ 78
305/310***
88/ 94
24
44
47
63
70
82
53/ 53
78/ 81
91/ 97
27
47
50
66
73
85
70/ 70
95/ 99
36
58
74
81
93
105
323/331***
338/348***
360/373***
305/305
327/330
339/344***
357/365***
372/382***
394/407***
365/365
387/390***
398/403***
431/442***
453/467***
469/485***
109/118
126/138
159/167
112/121
129/141
154/170
109/115
147/159
172/188
190/209
136
152
155
169
175
186***
158
174
177
191***
197
208
183
203
217
223***
234***
243***
—8—
LEGEND AND NOTES FOR TABLES 3A-3D
LEGEND
FLA — Full Load Amps
HACR — Heating, Air Conditioning
IFM — Indoor Fan Motor
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps
MOCP — Maximum Overcurrent
NEC — National Electrical Code
OFM — Outdoor-Fan Motor
RLA — Rated Load Amps
*Heaters are field installed only.
†Minimum unit disconnect size is used to determine minimum discon-
nect per NEC.
**Heater capacity (kW) is based on heater voltage of 208 v, 240 v,
480 v. If power distribution voltage to unit varies from rated heater
voltage, heater kW will vary accordingly.
††Fuse or HACR circuit breaker.
***Factory-installed disconnect is not available for these units when
electric heat package is installed.
NOTES:
1. In compliance with NEC requirements for multimotor and combina-
2. Unbalanced 3-Phase Supply Voltage
and Refrigeration
Protection
tion load and equipment (refer to NEC Articles 430 and 440), the
overcurrent protective device for the unit shall be fuse or HACR
breaker.
Never operate a motor where a phase imbalance in supply voltage
is greater than 2%.
cent of voltage imbalance.
% Voltage Imbalance
= 100 x
max voltage deviation from average voltage
Use the following formula to determine the per-
average voltage
Example: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
Average Voltage =
Determine maximum deviation from average voltage:
(AB) 457 – 452 = 5 v
(BC) 464 – 457 = 7 v
(AC) 457 – 455 = 2 v
Maximum deviation is 7 v.
Determine percent of voltage imbalance:
% Voltage Imbalance = 100 x
= 1.53%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is more than
2%, contact your local electric utility company immediately.
3. Non-fused disconnect switch cannot be used when rooftop unit
electrical ratings exceed 80 amps.
452 + 464 + 455
3
1371
=
3
= 457
7
457
—9—
B. Field Control Wiring
Install a Bryant-approved accessory thermostat assembly
according to installation instructions included with the
accessory. Locate the thermostat assembly on a solid wall in
the conditioned spac e to sense average temperature in accordance with thermostat installation instructions.
NOTE: If using a Bryant elect ronic therm ostat, set th e thermostat configuration for “non-heat pump operation.” This
family of products does not require an “O” terminal to energize the reversing valve.
Route the therm ostat ca ble or eq uivale nt singl e leads of colored wire from the subbase terminals to the low-voltage connections on the unit (shown in Fig. 7) as described in Steps 1
through 4 below.
NOTE: For wire runs up to 50 ft, use no. 18 AWG (American
Wire Gage) insulated wire (35 C minimum). For 51 to 75 ft,
use no. 16 AWG insulated wire (35 C minimum). For over
75 ft, use no. 14 AWG insulated wire (35 C minimum). All
wire larger than no. 18 AWG cannot be directl y c onnect ed to
the thermostat and will require a junction box and splice at
the thermostat.
1. If the unit is mounted on roof curb and accessory
thru-the-curb service plate connection is used, route
wire through the connection plate.
2. Pass control wires throug h the hole provided on the
unit (see connection D in Connection Sizes table
Fig. 5).
3. Feed wi re through the racew ay bu ilt into the co rner po st
to the 24-v barrier located on the left side of the control
box. See Fig. 8. The raceway provides the UL required
clearance between the high-and low-voltage wiring.
4. Connect the thermostat wires to the screw termina ls
of the low-voltage connector (se e Fig. 7).
NOTE: If thru-the-bottom power connections are used refer
to the accessory installation instructions for information on
power wiring. Refer to Fig. 5 for drilling holes in the
basepan.
C. Defrost Board
The defrost board timer cycle is set to 30 minutes. To change
the cycle time, remove the wire from defrost board connected
to the 30 minute quick-connect. See Fig. 9. Connect the wire
to the 50 to 90 minute quick-connects on the defrost board,
depending on the desired defrost time.
D. Heat Anticipator Settings
For units with electric heat, set heat anticipator settings as
shown in Table 4.
VI. STEP 6 — ADJUST FACTORY-INSTALLED OPTIONS
A. Disconnect Switch
The optional disconnect switch is non-fused. The switch can
be locked in plac e for safety pur poses. The disconn ect has a
maximum rating of 80 amperes and cannot be used if rooftop
electrical rating exceeds 80 amperes.
B. Manual Outdoor-Air Damper
The outdoor-air hood and screen are attached to the basepan
at the bottom of the unit (for shipping).
Assembly:
1. Determine the amount of ventilation requi red for the
building. Record the amount for use in Step 8.
2. Remove the filter access panel by raising the panel
and swinging it outward. The panel is now disengaged from the track and can be removed. No tools
are required to remove the filter access panel.
Remove the outdoor-air opening panel. Save panels
and screws. See Fig. 10.
3. Separate the hood and screen from the basepan by
removing the screws and brackets securing them.
Save all screws and discard brackets.
4. Replace the ou tdoor air opening pa nel.
5. Place the hood on the front of the outdoor air opening
panel. See Fig. 11 for hood details. Secure the top of
the hood with the 6 screws removed in Step 3. See
Fig. 12.
6. Remove and save the 8 scre ws (4 on each side) from
the sides of the manual outdoor-air damper.
7. Align the screw holes on the hood with the screw
holes on the sid e of manual outdoor-air dam per. See
Fig. 11 and 12. Secure the hood with the 8 screws
from Step 6.
8. Adjust the minimum position setting of the damper
blade by adjusting the manual outdoor-air adjustment screws on the front of the damper blade. See
Fig. 10. Slide the blade vertically until it is in the
appropriate position determined by Fig. 13. Tighten
the screws.
9. Remove and save the screws cu rrent ly o n the si des of
the hood. Insert the screen. Secure the screen to the
hood using the screws. See Fig. 12.
10. Replace the filter access panel. Ensure that the filter
access panel slides along the tracks and is securely
engaged.
UNIT
Heater kW*
10.4, 16.0 0.3 NA NA
549B
*kW is based on 240 or 480 v.
24.8, 32.0 0.6 0.3 0.3
42.4, 50.0 0.9 0.6 0.3 41.7, 50.0 0.6 0.3 0.3
Table 4 — Heat Anticipator Settings
208/230 460
Configuration
1-Stage
2-Stage
Stage 1 Stage 2 Stage 1 Stage 2
UNIT VOLTAGE
Heater kW*
13.9, 16.5
27.8, 33.0
—10—
Configuration
1-Stage
0.3 NA NA
2-Stage
COOL STAGE 1
FAN
HEAT STAGE 1
COOL STAGE 2
HEAT STAGE 2
24 VAC HOT
24 VAC COM
N/A
OUTDOOR AIR
SENSOR
THERMOSTAT DIPSWITCH SETTINGS
ON
OFF
B
A
C
Y1/W2
G
W/W1
Y/Y2
O/W2
R
C
S1
S2
D
R
G
Y1
Y2
W1
W2
C
IPD/X
WIRE
CONNECTIONS
TO
LOW-VOLTAGE
SECTION
(CONNECTION
BOARD)
LEGEND
Field Wiring
NOTE: Underlined letter indicates active thermostat output when configured for A/C operation.
Fig. 7 — Low-Voltage Connections With or
Without Economizer or Two-Position Damper
Fig. 9 — Defrost Board
DISCONNECT
BOARD
DISCONNECT
SWITCH
(OPTIONAL)
RACEWAY
COMPRESSOR
NO. 2
CONVENIENCE
OUTLET
HOLE IN
END
PANEL
COMPRESSOR NO. 1
Fig. 8 — Typical Field Control Wiring Raceway
FILTER
ACCESS
PANEL
OUTDOOR AIR
OPENING
PANEL
SCREWS
(SIDE)
MANUAL
OUTDOOR-AIR
ADJUSTMENT
SCREWS
DAMPER
BLADE
Fig. 10 — Damper Panel with Manual
Outdoor-Air Damper Installed
—11—
SCREW
HOLES
(TOP)
Fig. 11 — Outdoor-Air Hood Details
C. Optional EconoMi$er IV
See Fig. 14 for EconoMi$er IV component locations.
NOTE: These instructions are for installing the optional
EconoMi$er IV. Refer to the accessory EconoMi$er IV in stal lation instr uctions when field inst alling an EconoMi$er I V
accessory.
1. To remove the existing unit filter access panel, raise
the panel and swing the bottom outward. The panel is
now disengaged from the track and can be removed.
See Fig. 15.
2. The box with the economizer hood components is
shipped in the compa rtment behind the economizer.
The EconoMi$er IV controller is mounted on top of
the EconoMi$er IV in the position shown in Fig. 14.
To remove the component box f rom it s shippi ng posi tion, remove the screw holding the hood box bracket
to the top of the economizer. Slide the hood box out of
the unit. See Fig. 16.
IMPORTANT: If the power exhaust accessory is to be
installed on the unit, the hood shipped with the unit will not
be used and must be discarded. Save the aluminum filter
for use in the power exhaust hood assembly.
3. The indoor coi l acc ess pan el wi ll b e us ed a s the to p of
the hood. Remove the screws along the sides and
bottom of the indoor coil access panel. See Fig. 17.
4. Swing out indoor coil access panel and insert the hood
sides under the panel (hood top). Use the screws provided to attach the hood sides to the hood top. Use screws
provided to attach the hood sides to the unit. See Fig. 18.
HOOD
HOOD
SCREEN
LOCATION
(SCREEN
NOT
SHOWN)
Fig. 12 — Optional Manual Outdoor-Air
Damper with Hood Attached
ECONOMI$ER IV
CONTROLLER
WIRING
HARNESS
ACTUATOR
OUTSIDE AIR
TEMPERATURE SENSOR
LOW AMBIENT
SENSOR
Fig. 14 — EconoMi$er IV Component Locations
FILTER ACCESS PANEL
Fig. 13 — Outdoor Air Damper Position Setting
INDOOR COIL ACCESS PANEL
Fig. 15 — Typical Access Panel Locations
—12—
x
o
B
d
o
o
H
Fig. 16 — Hood Box Removal
HOOD BOX
BRACKET
INDOOR
COIL
ACCESS
PANEL
CAULK
HERE
SIDE
PANEL
TOP
SIDE
PANEL
INDOOR
COIL
ACCESS
PANEL
5. Remove the shipping tape holding the economizer
barometric relief damper in place.
6. Insert the hood divider between the hood sides. See
Fig. 18 and 19. Secure hood divider with 2 screws on
each hood side. The hood di vider is also used as the
bottom filter rack for the aluminum filter.
7. Open the filter clips which are located underneath
the hood top. Insert the aluminum filter into the
bottom filter rack (hood divider) . Push the filter into
position pa st th e op en fi lter c lip s . Cl ose the f ilt er c lip s
to lock the filter into place. See Fig. 19.
8. Caulk the ends of the joint between the unit top panel
and the hood top. See Fig. 17.
9. Replace the filter access panel.
10. Install all EconoMi$ er IV ac ces sori es. Ec onoM i$e r I V
wiring is shown in Fig. 20.
Barometric flow capacity is shown in Fig. 21. Outdoor air
leakage is shown in Fig. 22. Return air pressure drop is
shown in Fig. 23.
D. EconoMi$er IV Standard Sensors
Outdoor Air Temperature (OAT) Sensor
The outdoor air temperature sensor (HH57AC074) is a 10 to
20 mA device used to measure the outdoo r-air temperature.
The outdoor-air temperature is used to determine when the
EconoMi$er IV can be used for free cooling. The sensor is
factory-installed on the EconoMi$er IV in the outdoor airstream. See Fig. 14. The operating range of temperature
measurement is 40 to 100 F.
Supply Air Temperature (SAT) Sensor
The supply air temperature sensor is a 3 K thermistor
located at the inlet of the indoor fan. See Fig. 24. This sensor
is factory installed. The operating range of temperature
measurement is 0° to 158 F. See Table 5 for sensor
temperature/resistance values.
The temperature sensor l ooks like an eyelet terminal with
wires running to it. The sensor is located in the “crimp end”
and is sealed from moisture.
Outdoor Air Lockout Sensor
The Economi$er IV is equipped with an ambient tempera-
ture lockout switch located in the outdoor airstream which is
used to lock out the compressors below a 42 F ambient temperature. See Fig. 14.
Fig. 17 — Indoor Coil Access Panel Relocation
LEFT
HOOD
SIDE
B
24 9/16”
HOOD DIVIDER
SCREW
40 3/8”
Fig. 18 — Outdoor-Air Hood Construction
22 1/4”
DIVIDER
OUTSIDE
AIR
HOOD
CLEANABLE
BAROMETRIC
RELIEF
ALUMINUM
FILTER
FILTER
Fig. 19 — Filter Installation
TOP
PANEL
INDOOR COIL
ACCESS PANEL
FILTER
CLIP
—13—
FOR OCCUPANCY CONTROL
REPLACE JUMPER WITH
FIELD-SUPPLIED TIME CLOCK
LEGEND
DCV— Demand Controlled Ventilation
IAQ — Indoor Air Quality
LA — Low Ambient Lockout Device
OAT — Outdoor-Air Temperature
POT— Potentiometer
RAT— Return-Air Temperature
Potentiometer Defaults Settings:
Power Exhaust Middle
Minimum Pos. Fully Closed
DCV Max. Middle
DCV Set Middle
Enthalpy C Setting
Table 5 — Supply Air Sensor
Temperature/Resistance Values
TEMPERATURE (F) RESISTANCE (ohms)
–58 200,250
–40 100,680
–22 53,010
–4 29,091
14 16,590
32 9,795
50 5,970
68 3,747
77 3,000
86 2,416
104 1,597
122 1,080
140 746
158 525
176 376
185 321
194 274
212 203
230 153
248 116
257 102
266 89
284 70
302 55
NOTES:
1. 620 ohm, 1 watt 5% resistor should be removed only when using differential
enthalpy or dry bulb.
2. If a separate field-supplied 24 v transformer is used for the IAQ sensor power
supply, it cannot have the secondary of the transformer grounded.
3. For field-installed remote minimum position POT, remove black wire jumper
between P and P1 and set control minimum position POT. to the minimum
position.
Fig. 20 — EconoMi$er IV Wiring
2500
2000
1500
1000
500
FLOW IN CUBIC FEET PER MINUTE (cfm)
30
25
20
15
10
5
0
FLOW IN CUBIC FEET PER MINUTE (cfm)
Fig. 22 — Outdoor Air Damper Leakage
0
0.05
0.15
STATIC PRESSURE (in. wg)
0.25
Fig. 21 — Barometric Flow Capacity
0.13 0.20 0.22 0. 25 0.30 0.35 0.40 0.45 0.50
STATIC PRESSURE (in. wg)
—14—
6000
5000
4000
3000
2000
1000
0
0.05 0.10 0.15 0. 20 0.25 0.30 0.35
FLOW IN CUBIC FEET PER MINUTE (cfm)
STATIC PRESSURE (in. wg)
Fig. 23 — Return Air Pressure Drop
SUPPLY AIR
TEMPERATURE
SENSOR
MOUNTING
LOCATION
SUPPLY AIR
TEMPERATURE
SENSOR
Fig. 24 — Supply Air Sensor Location
E. EconoMi$er IV Control Modes
Determine the EconoMi$er IV control mode before set up of the
control. Some modes of operation may require different sensors.
Refer to Table 6. The EconoMi$er IV is su pplied from the fa ctory with a supply air temperature sensor and an outdoor air
temperature sensor. This allows for operation of the
EconoMi$er IV with outdoor air dry bulb changeover control.
Additional accessories can be added to allow for different
types of changeover control and operation of the EconoMi$er
IV and unit.
Table 6 — EconoMi$er IV Sensor Usage
ECONOMI$ER IV WITH OUTDOOR AIR
APPLICATION
Outdoor Air Dry Bulb
Differential Dry Bulb CRTEMPSN002A00*
Single Enthalpy HH57AC078
Differential Enthalpy
for DCV Control
CO
2
using a Wall-Mounted
Sensor
CO
2
CO
for DCV Control
2
using a Duct-Mounted
CO2 Sensor
*CRENTDIF004A00 and CRTEMPSN002A00 accessories are used on many
different base units. As such, these kits may contain parts that will not be
needed for installation.
†33ZCSENCO2 is an accessory CO
**33ZCASPCO2 is an accessory aspirator box required for duct-mounted
applications.
††CRCBDIOX005A00 is an accessory that contains both 33ZCSENCO2 and
33ZCASPCO2 accessories.
33ZCSENCO2†
33ZCASPCO2**
DRY BULB SENSOR
Accessories Required
None. The outdoor air dry bulb sensor
is factory installed.
HH57AC078
and
CRENTDIF004A00*
33ZCSENCO2
and
sensor.
2
CRCBDIOX005A00††
OR
Outdoor Dry Bulb Changeover
The standard controller is shipped from the factory configured
for outdoor dry bulb changeover control. The outdoor air and
supply air tempe rature sensor s are included as standard. For
this control mode, the outdoor temp erature is compa red to an
adjustable set point sel ected on the control. If the outdoor-air
temperature is above the set point, the EconoMi$er IV will
adjust the outdoor-air dampers to minimum position. If the
outdoor-air temperature is below the set point, the posi tion of
the outdoor-air dampers will be con trol led to provi de free coo ling using outdoor air. When in this mode, the LED next to the
free cooling set point potentiometer will be on. The changeover
temperature set point is controlled by the free cooling set point
potentiometer located on the cont rol. See Fig. 25. The scale on
the potentiometer is A, B, C, and D. See Fig. 26 for the corresponding te mp e r ature changeover v a lue s.
Differential Dry Bulb Control
For differential dry bulb control the standard outdoor dry
bulb sensor is used in conjunction with an additional accessory dry bulb sensor (part number CRTEMPSN002A00). The
accessory senso r must be mounted in the return airstream.
See Fig. 27. Wiring is provided in th e EconoMi$e r IV wiring
harness. See Fig. 20.
In this mode of operation, the outdoor-air temperature is
compared to the return-air temper ature and the lower temperature airstream is used for cooling. When using this mode
of changeover control, turn the enthalpy set point potentiometer fully clockwise to the D setting. See Fig. 25.
Outdoor Enthalpy Changeover
For enthalpy control, accessory enthalpy sensor (part num-
ber HH57AC078) is required. Replace the standard outdoor
dry bulb temperature sensor with the accessory enthalpy
sensor in the same mounting location. See Fig. 14. When the
outdoor air enthalpy rises above the outdoor enthalpy
changeover set point, the outdoor-air damper moves to its
minimum position. The outdoor enthalpy changeover set
point is set with the ou tdoor enthalpy set poi nt potentiometer on the EconoMi$er IV controller. The set points are A, B,
C, and D. See Fig. 28. The factory-installed 620-ohm jumper
must be in place across terminals SR and SR+ on the
EconoMi$er IV controller. See Fig. 14 and 29.
Differential Ent halpy Control
For differential enthalpy control, the EconoMi$ er IV co ntrol -
ler uses two enthalpy sensors (HH57AC078 and
CRENTDIF004A00), one in the outside air and one in the
return air duct. The EconoMi$er IV controller compares the
outdoor air enthalpy to the return a ir enthalpy to de termine
EconoMi$er IV use. The controller selects the lower enthalpy
air (return or outdoor) for cooling. For example, when the
outdoor air has a lower enthalpy than the return air, the
EconoMi$er IV opens to bring in outdoor air for free cooling.
Replace the standard outside air dry bulb temperature sensor with the acc essor y enth alpy senso r in th e same mou nting
location. See Fig. 14. Mount th e return air enthalpy sen sor
in the return air duct. See Fig. 27. Wiring is provide d in the
EconoMi$er IV wiring harness. See Fig. 20. The outdoor
enthalpy changeover set point is set with the outdoor
enthalpy set point potentiometer on the EconoMi$er IV
controller. When using this mode of changeover control, turn
the enthalpy set point potentiometer fully clockwise to the D
setting.
—15—
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