Trane UHEC-IM-7A Maintenance and service guide

Since the American-Standard Company has a policy of continuous product improvement, it reserves the right to change
specifications and design without notice. The installation and servicing of the equipment referred to in this booklet should
be done by qualified, experienced technicians.
Electric
Unit Heater
Library Service Literature
Product Section Air Terminal Devices & Heating Products
Product Unit Heaters — Electric
Model UHEC
Literature Type Installation/Maintenance
Sequence 7A
Date February 1997
File No. SV-TD-UH-UHEC-IM-7A-297
Supersedes EUH-IM-7A-895
Installation
Maintenance UHEC-IM-7A
Model UHEC
9597

3 Model Number Description
4 General Information
Literature Change History
Unit Inspection
5 Installation
Location
Unit Mounting
—Horizontal Air Delivery
—Vertical Air Delivery
Electrical Wiring
16 Maintenance
Electrical Circuitry
Cleaning
Lubrication
17 Trouble Analysis
Tables and Figures
5 Table 1
Air Delivery Characteristics
6 Table 2
Metric Air Delivery
Characteristics
14 Table 3
Electrical Data
5 Figure 1
UHEC Unit Dimensions
6 Figure 2 - Horizontal
Wall/Ceiling Swivel
Bracket Dimensions and
Clearance Requirements
7 Figure 2a
Accessory Fan Guard
Installation
9 Figure 3
Wall/Ceiling Swivel
Bracket Installation for
Horizontal Air Delivery
9 Figure 3a
Dust Shield Installation
Horizontal Air Delivery
10 Figure 4 - Vertical
Ceiling Hanger Bracket
Dimensions and
Clearance Requirements
12 Figure 5
Ceiling Hanger Bracket
Installation
13 Figure 5a
Heaters 7.5 KW, 10 KW,
25 KW, 30 KW, 40 KW, 50KW
13 Figure 5b
Heaters 15 KW and 20 KW
Unit Wiring Diagrams
18 Figure 6
Models UHEC031A0C0,
031B0C0, 031C0C0, 051A0C0,
051B0C0 and 051C0C0
19 Figure 7
Models UHEC031AACA,
051AACA 031CACA, 051CACA,
071CACA and 101CACA
20 Figure 8
Models UHEC032AACA and
052AACA
21 Figure 9
Models UHEC031BACA,
051BACA, 032BACA and
052BACA
22 Figure 10
Models UHEC032A0C0,
032B0C0, 052A0C0 and 052B0C0
23 Figure 11
Models UHEC072AACA and
102AACA
24 Figure 12
Models UHEC072BACA and
102BACA
25 Figure 13
Models UHEC033DACA,
053DACA, 073DACA, 103DACA,
153DACA and 203DACA
26 Figure 14
Model UHEC153AACA
27 Figure 15
Models UHEC153BACA and
203BACA
28 Figure 16
Models UHEC253AACA,
303AACA, 403AACA and
503AACA
29 Figure 17
Models UHEC253BACA,
303BACA, 403BACA and
503BACA
30 Figure 18
Models UHEC253DACA and
303DACA
31 Figure 19
Model UHEC403DACA
32 Figure 20
Model UHEC503DACA
Table of
Contents
2 ©American Standard Inc 1997 UHEC-IM-7A

Trane products are identified by a
multiple character model number that
precisely identifies a particular type of
unit. Following is an explanation of the
model number code used to identify
the Electric Unit Heater. It will enable
the owner or Service engineer to
define operation, components and
accessories.
Important! Be sure to reference the
model and serial numbers (when
present) printed on the panel
nameplate label when ordering
replacement parts or requesting
service.
Digits 1,2,3
Product Type
UHE = Unit Heater, Electric
Digit 4
Development Sequence
C = Development Sequence
Digits 5,6
Kw Rating
03 = 3.3 Kw
05 = 5.0 Kw
07 = 7.5 Kw
10 = 10.0 Kw
15 = 15.0 Kw
20 = 20.0 Kw
25 = 25.0 Kw
30 = 30.0 Kw
40 = 40.0 Kw
50 = 50.0 Kw
Digit 7
Element Phase
1 = Single-Phase (Not available
w/480-volt)
2 = Single or Three-Phase
3 = Three-Phase (Not available
w/277-volt)
Digit 8
Element and Motor Voltage
A = 208 Volts
B = 208/240 Volts
C = 277 Volts
D = 480 Volts
Digit 9
24-Volt Transformer
0 = None — Wired For Direct Line
Voltage
A = Transformer — For 24 Volt
Control Circuits
Digit 10
Design Sequence
C = Design Sequence
Digit 11
Contactors
0 = None — Wired For Direct Line
Voltage
A = Contactor — For 24 Volt Control
Circuits
Model Number
Description
UHEC-IM-7A 3

Literature Change
History
UHEC-IM-7 (September 1992)
Original issue of manual covering “C”
design sequence units.
EUH-IM-7A (August 1995)
Revision of electrical data and
addition of accessory fan guard.
UHEC-IM-7A (February 1997)
Manual revised to include literature
name change to reflect model
number, addition of junction box
volume table and addition of
anemostat diffuser.
Warnings and Cautions
Warnings and cautions appear at
appropriate intervals throughout this
manual. Your personal safety and the
proper operation of this machine
require that you follow them carefully.
The Trane Company assumes no
liability for installations or servicing
performed by unqualified personnel.
Warnings alert the equipment
rigger, owner/operator and service
personnel to potential hazards that
could result in personal injury or
death.
Cautions are provided to alert
personnel to conditions that may
result in equipment or property
damage.
For your convenience, typical unit
wiring diagrams are provided at the
end of this booklet.
Unit Inspection
When the unit is delivered to the job
site, verify that the correct unit has
been shipped by comparing the
information on the unit nameplate
without ordering, submittal and
shipping information.
Inspect the unit —including its internal
components—for damage. Rotate the
fan to ensure that it turns freely.
Report any apparent damage or
material shortage to the carrier and
make a “unit damage or shortage”
notation on the carrier’s delivery
receipt. Specify the extent and type of
damage found and notify the
appropriate Trane sales office. Do not
proceed with installation of a damaged
unit without sales office approval.
General
Information
4 UHEC-IM-7A

General
All Electric unit heaters are shipped
fully assembled. Installation involves
mounting build-in and remote
accessories, wiring optional control
devices, running electrical wiring to
the unit and mounting the unit.
Refer to Figure 1 for unit dimensions
and sipping weights.
Location
To ensure proper delivery of the
heated air to the desired areas, follow
the guidelines for maximum distance
of throw and mounting heights
provided in Table 1. Keep units away
from obstructions that will impede the
full and natural flow of air.
See Figures 2 and 4 for minimum wall,
ceiling and floor clearance
requirements.
Installation
Table 1
Air Delivery Characteristics
Unit Heater
Capacity
(Kw Rating) Motor Approximate
Air
Rise
Horizontal
Air
Throw
Recommended
Mounting Height
HP RPM CFM Horizontal Vertical
3.3 1/125 1550 400 26 F 12 Ft. 9 Ft. 9 Ft.
5.0 1/125 1550 400 26 F 12 Ft. 9 Ft. 9 Ft.
7.5 1/50 1550 700 34 F 22 Ft. 10 Ft. 2 Ft.
10.0 1/50 1550 700 45 F 22 Ft. 10 Ft. 14 Ft.
15.0 1/20 1550 1100 43 F 32 Ft. 11 Ft. 20 Ft.
20.0 1/20 1550 1100 57 F 32 Ft. 12 Ft. 18 Ft.
25.0 1/12* 1550/1250 2000/1800 40 F/44 F 45 Ft. 12 Ft. 22 Ft.
30.0 1/12* 1550/1250 2000/1800 47 F/53 F 40 Ft. 12 Ft. 20 Ft.
40.0 1/4** 1550/1310 3100/2800 40 F/45 F 55 Ft. 15 Ft. 25 Ft.
50.0 1/4** 1550/1310 3100/2800 51 F/56 F 50 Ft. 15 Ft. 22 Ft.
Notes:
* 480 volt units - 1/15 horsepower motor
**480 volt units = 1/5 horsepower motor
Figure 1
UHEC Unit Dimensions
Unit
Size Dimensions Shipping Weight
H W D Lbs Kg
03, 05 17 3/4"
(451 mm) 14 15/32" (368mm) 6 1/2" (165 mm) 27 12.2
07, 10 24 5/16"
(618 mm) 21 1/2" (546 mm) 6 1/2" (165 mm) 50 22.7
15, 20 28 11/16"
(729 mm) 21 1/2" (546 mm) 6 1/2" (165 mm) 65 29.5
25,30,
40 & 50 34" (864 mm) 29 1/4" (743 mm) 10 1/8" (256 mm) 120 54.4
UHEC-IM-7A 5

Table 2
Metric Air Delivery Characteristics
Unit Htr
Capacity
KW
Rating Motor Data
Airflow
at
Outlet
(L/S)
Approx.
Air Rise
@ Outlet
(C)
Horz.
Air
Throw
(M)
Rec. Max.
Mounting
Height (M)
Watts R.P.S. Horz. Vert.
3.3 6 25.8 189 14.4 3.7 2.7 2.7
5.0 6 25.8 189 22.2 3.7 2.7 2.7
7.5 14 25.8 330 18.9 6.7 3.0 3.7
10 14 25.8 330 25.0 6.7 3.0 4.3
15 37 25.8 519 23.9 9.8 3.4 6.1
20 37 25.8 519 31.7 9.8 3.7 5.5
25 62 25.8 944/
849 22.2/ 24.4 13.7 13.7 3.7 3.7 6.7 6.7
25
480/3 Mtr 50 25.8 944/ 849 22.2/ 24.4 13.7 13.7 3.7 3.7 6.7 6.7
30 62 25.8 944/
849 26.1/ 29.4 12.2 12.2 3.7 3.7 6.1 6.1
30
480/3 Mtr 50 25.8 944/ 849 26.1/ 29.4 12.2 12.2 3.7 3.7 6.1 6.1
40 186 25.8 1463/
1321 22.2/ 25.0 16.8 16.8 4.6 4.6 7.3 7.3
40
480/3 Mtr 149 25.8 1463/ 1321 22.2/ 25.0 16.8 16.8 4.6 4.6 7.3 7.3
50 186 25.8 1463/
1321 28.3/ 31.1 15.2 15.2 4.6 4.6 6.7 6.7
50
480/3 Mtr 149 25.8 1463/ 1321 28.3/ 31.1 15.2 15.2 4.6 4.6 6.7 6.7
1.25 through 50 Kw models are equipped with two-speed motors for Hi-Lo fan operation
with addition of fan switch option.
Installation
Dimensions in ( ) are in millimeters.
Figure 2
Wall/Ceiling Swivel
Bracket Dimensions and
Clearance Requirements
(Horizontal Air Delivery)
6 UHEC-IM-7A

Characteristic Unit Size (Kw Rating)
03,05 07 thru 20 25 thru 50
Use this Mounting Bracket:
Model No.
Order No. A5105 236-723 A5120 236-724 A5150 236-725
Mounting Bracket
Weight 6 Lbs. (2.7 Kg) 9 Lbs. (4.1 Kg) 11 Lbs. (5.0 Kg)
Dimensions
A 19-15/16"
(489 mm) 23" (584 mm) 26-21/32" (677 mm)
B 10-1/2"
(267 mm) 12" (305 mm) 13-1/2" (343 mm)
C 9-1/4"
(235 mm) 19-1/8" (486 mm) 19-7/8" (505 mm)
D 3-31/32"
(101 mm) 7-17/32" (191 mm) 10-27/32" (275 mm)
E 5-1/8"
(130 mm) 5-1/8" (130 mm) 8-11/16" (221 mm)
Minimum Distance from
Ceiling to Unit 12" (305 mm) 18" (457 mm) 18" (457 mm)
Minimum Distance from
Adjacent Surface to Unit 12" (305 mm) 12" (305 mm) 12" (305 mm)
Minimum Distance from
Floor to Unit * 7 Ft. (2.4 m) 7 Ft. (2.4 m) 7 Ft. (2.4 m)
* Do not exceed unit’s maximum mounting height; see Table 1.
Order No. Model No. Unit Size Number of
Holes Dim. from Edge Center to Center Dimension
233-930 OFG-5101 2-5 KW 41/4" (6.4mm) 3 3/4" (95mm)
233-932 OFG-5102 7-20 KW 41/4" (6.4mm) 4 3/4" (121mm)
233-935 OFG-5103 25-50 KW 61/4" (6.4mm) 4 3/4" (121mm)
1. For units with existing holes in louver frame, the fan guard snaps into place.
2. To retrofit the fan guard, holes must be drilled 1/8" (3.2mm) diameter as
shown in Figure 2a.
3. OSHA approved.
4. Dimensions in ( ) are in millimeters.
Figure 2a
Accessory Fan Guard Installation
Installation
UHEC-IM-7A 7

Unit Mounting
Note: The wall and/or ceiling structure
must be of sufficient strength to
support the combined weight of the
heater, mounting bracket and any
added accessories.
Each heater can be mounted in either
a horizontal or vertical air discharge
position using factory-supplied
mounting brackets or mounting
devices supplied by the installing
contractor.
Four position weld nuts are provided
on the top and back of the unit heater
casing to facilitate the use of
field-supplied drill rods or eyebolts
with chains, or factory-supplied;
mounting brackets, capscrews and
lockwashers.
Refer to Figures 2 and 4 for mounting
bracket dimensions and clearance
requirements.
WARNING!
Unit weights are provided in Figure
1. Use special care when lifting
units to mounting position to avoid
possible personal injury or
equipment damage.
Note: If a 5/16-inch (7.9 mm),
all-thread rod is used to mount the unit
heater vertically, do not screw the rod
more than 1/2-inch (12.7 mm) beyond
the inside of the unit case.
Horizontal Air Delivery
The combination wall/ceiling swivel
bracket can be used to suspend a unit
from either the wall or ceiling to
provide horizontal air delivery. See
Figure 3. For mounting bracket model
information, minimum clearance
requirements and bracket dimensional
data, refer to Figure 2.
Note: To simplify unit installation, be
sure to complete the mounting and
wiring of any optional accessories
used before mounting the unit.
Use the instructions provided
below—along with Figure 3—to
mount the electric unit heater for
horizontal air delivery:
1. Attach the hanger base to the top of
the heater with the four 5/16" (7.9
mm) x 18 capscrews and
lockwashers provided.
2. Attach the main hanger frame to
the desired location on the wall or
ceiling using field-supplied lag
screws or other suitable fasteners.
3. Lift the unit into position. Then,
insert the hanger base stud through
the hole in the main hanger frame
and install the lock nut on the stud.
Tighten the lock nut to within two
turns of being completely tightened
down.
4. Swivel the heater into the desired
position, and finish tightening the
lock nut.
Installation
8 UHEC-IM-7A

Figure 3
Wall/Ceiling Swivel Bracket Installation
for Horizontal Air Delivery
Horizontal Ceiling Suspension
Horizontal Wall Suspension
Installation
Wall Mounted Bracket Ceiling Mounted Bracket
Customer Supplied Bracket or Direct
Connection to Building Structural Member
Figure 3a
Dust Shield Installation for Horizontal Air
Delivery
UHEC-IM-7A 9

Figure 4
Ceiling Hanger Bracket
Dimensions and
Clearance Requirements
(Vertical air Delivery)
Characteristic Unit Size (Kw Rating)
03,05 07,10 15,20 25 thru 50
Use this Mounting Bracket:
Model No.
Order No. V5105 236-726 V5120 236-727 V5120 236-727 V5150 236-728
Mounting Bracket
Weight 9 Lbs. (4.1 Kg) 13 Lbs. (5.9 Kg) 13 Lbs. (5.9 Kg) 13 Lbs. (5.9 Kg)
Dimensions
A2-7/16"
(62 mm) 3-1/2" (89 mm) 3-1/2" (89 mm) 6-13/16" (173 mm)
B1-5/32"
(29 mm) 1-7/8" (48 mm) 1-7/8" (48 mm) 1-7/8" (48 mm)
C5-7/16"
(138 mm) 6-3/8" (162 mm) 6-3/8" (162 mm) 5-5/8" (143 mm)
D11-5/32"
(283 mm) 16-1/16" (408 mm) 20-7/16" (519 mm) 26-1/2" (673 mm)
E26"
(660 mm) 36-9/16" (929 mm) 36-9/16" (929 mm) 42" (1067 mm)
F9-1/8"
(232 mm) 13-7/8" (352 mm) 13-7/8" (352 mm) 13-7/8" (352 mm)
G18-3/4"
(476 mm) 24-1/2" (622 mm) 24-1/2" (622 mm) 28-1/16" (713 mm)
Minimum Distance from Ceiling
to Unit 12-1/8" (311 mm) 18" (457 mm) 18" (457 mm) 18" (457 mm)
Minimum Distance from
Adjacent Surface to Unit 12" (305 mm) 24" (610 mm) 24 (610 mm) 24" (610 mm)
Minimum Distance from Floor
to Unit * 7 Ft. (2.4 m) 7 Ft. (2.4 m) 7 Ft. (2.4 m) 7 Ft. (2.4 m)
* Do not exceed unit’s maximum mounting height; see Table 1.
Installation
10 UHEC-IM-7A

Vertical Air Delivery
A ceiling hanger bracket is used to
suspend a unit heater from the ceiling
to provide vertical air delivery; see
Figure 5. For mounting bracket model
information, minimum clearance
requirements and dimensional data,
refer to Figure 4.
Note: To simplify unit installation, be
sure to complete the mounting and
wiring of any optional accessories
used before mounting the unit.
Use the instructions provided
below—along with Figure 5—to
mount the electric unit heater for
vertical air delivery:
1. Attach the short angle brackets to
the back of the unit heater with the
four 5/16" (8mm) X 18 capscrews
and lockwashers provided. Be sure
that the vertical leg of each angle
bracket faces the top and bottom
(ends) of the heater.
2. Attach the inverted U-frames to the
short angle brackets with the four
5/16" (8mm) X 18 capscrews,
washers, lockwashers and nuts
furnished with the unit.
3. Using the four 5/16" (8mm) X 18
capscrews, washers, lockwashers
and nuts provided, attach the long
angle brackets to the inverted
U-frames as shown in Figure 5.
4. Secure the unit-and-bracket
assembly to the ceiling in the
desired location; use field-supplied
hardware of sufficient strength to
support the combined weight of the
unit and any accessories.
Installation
UHEC-IM-7A 11

Figure 5
Ceiling Hanger Bracket
Installation for Vertical
Air Delivery
Diffuser Options
Optional diffusers lend added air pattern versatility to individual vertical down blown installations as shown in illustrations.
Description Used On Model No. Max. Mtg. Ht. Dim. A Dim. B Diffuser Pattern
1. Louver Diffuser
(Standard) Louvers can be
individually adjusted for
rectangular coverage over
doorways as an air curtain
or to meet rectangular floor
pattern heating
requirements.
3.3 & 5.0 KW
7.5 & 10.0 KW
15.0 & 20.0 KW
25.0 & 30.0 KW
40.0 & 50.0 KW
STD
STD
STD
STD
STD
9’ (2.7 M)
12’ (3.7 M)
18’ (5.5 M)
22’ (6.7 M)
24’ (7.3 M)
20’ ( 6.1 M)
40’ (12.2 M)
52’ (15.8 M)
75’ (22.9 M)
84’ (25.6 M)
10’ ( 3.0 M)
22’ ( 6.7 M)
30’ ( 9.1M)
42’ (12.8 M)
47’ (14.3 M)
2. General Distribution
(No Diffuser)
Trane’s Airchute Venturi
permits general downflow
air pattern distribution as
required at a higher
mounting height.
3.3 & 5.0 KW
7.5 & 10.0 KW
15.0 & 20.0 KW
25.0 & 30.0 KW
40.0 & 50.0 KW
N/R
N/R
N/R
N/R
N/R
9’ (2.7 M)
12’ (3.7 M)
18’ (5.5 M)
22’ (6.7 M)
24’ (7.3 M)
15’ ( 4.6 M)
30’ ( 9.1 M)
40’ (12.2 M)
55’ (16.8 M)
64’ (19.5 M)
3. Anemostat Diffuser
(Optional)
For application where draft
restriction is required at
lower unit mounting heights.
3.3 & 5.0 KW
7.5 & 10.0 KW
15.0 & 20.0 KW
25.0 & 30.0 KW
40.0 & 50.0 KW
N/A
AD5120
AD5120
AD5150
AD5150
— —
10’ ( 3.0 M)
15’ (4.6 M)
17’ (5.2 M)
20’ (6.1 M)
— —
30’ ( 9.1 M)
38’ (11.6 M)
50’ (15.2 M)
60’ (18.3 M)
4. Louver Cone Diffuser
(Optional)
Individually adjustable
blades permit increased
floor coverage at 45° open.
Additional throw is
accomplished when blades
are 90° vertical. Allow
higher mounting heights.
3.3 & 5.0 KW
7.5 & 10.0 KW
15.0 & 20.0 KW
25.0 & 30.0 KW
40.0 & 50.0 KW
N/A
RD5120
RD5120
RD5150
RD5150
45° 90°
— U —
10’ 3.0M 14’ 4.3M
14’ 4.3M 21’ 6.4M
20’ 6.1M 30’ 9.1M
18’ 5.5M 28’ 8.5M
45° 90°
— —
36’ 11.0M 30’ 9.1M
42’ 12.8M 35’ 10.7M
62’ 18.9M 44’ 13.4M
68’ 20.7M 54’ 16.5M
STD = Standard N/R = None Required N/A = Not Applicable
A
A
A
AB
Installation
12 UHEC-IM-7A

WARNING!
Disconnect electrical power source
before installing diffuser. Failure to
do so may result in serious
personal injury or death due to
electrical shock.
Anemostat Diffuser—Units 7.5 KW,
10 KW, 25 KW, 30 KW, 40 KW and
50 KW - See Figure 5a
1. Discard 1/4 - 20 x 1/2" (13 mm)
long machine screws (bag assy).
2. Line up holes in diffuser and the
venturi ring on the heater front.
3. Insert the 1/4 - 20 x 1 “ (25 mm)
long machine screws through the
venturi ring holes with the machine
screw head on the inside of the
venturi (See Note Below).
4. Slip the spacer over the machine
screw. Insert the machine screw
through the diffuser hole, install the
lockwasher, nut; then tighten. (See
detail above). (three places).
5. Place heater in operation.
Notes:
•Machine screw head must be on
the inside of the venturi ring.
•Caution must be exercised when
mounting the diffuser so as not to
damage the fan blade.
Anemostat Diffuser—15 KW and 20
KW - See Figure 5b
1. Discard 1/4 - 20 x 1" (25 mm) long
machine screws and 5/8” (16 mm)
long spacers.
2. Line up holes in diffuser and the
venturi ring (heater front).
3. Insert the 1/4 - 20 x 1/2 “ (13 mm)
long machine screws through the
venturi ring holes with the machine
screw head on the inside of the
venturi.
4. Attach the lockwasher, nut and
tighten. (three places).
5. Place unit in operation.
Notes:
•Machine screw head must be on
the inside of the venturi ring.
•Caution must be exercised when
mounting the diffuser so as not to
damage the fan blade.
Installation
Figure 5b Heaters 15 KW and
20 KW
Figure 5a Heaters 7.5 KW, 10 KW, 25 KW,
30 KW, 40 KW and 50 KW
UHEC-IM-7A 13

Electrical Wiring
Note: All wiring must comply with
NEC, CEC and local codes. Be sure
to check the unit voltage and phase
ratings listed on the heater data tape
on the back of the unit to ensure that
they are the same as the electrical
service supplied.
Refer to Table 2 for overcurrent
protection and wire size
recommendations. A unit wiring
diagram is attached to the inside of
the unit access panel; all wire leads
are identified in the same manner as
the codes used on this diagram.
Typical unit wiring diagrams are also
illustrated in Figures 6 through 20 at
the end of this manual.
Caution:
Use only copper conductors for
terminal connections to avoid
corrosion or overheating.
Note: To simplify installation of the unit
heater, be sure to complete the
mounting and wiring of any optional
accessories used before mounting the
unit.
WARNING!
To prevent injury or death due to
electrical shock, disconnect
electrical power source before
completing wiring connections to
unit.
Follow these basic guidelines when
wiring the unit heater:
1. Open the unit access panel. (It is
held closed by two 1/4-turn
fasteners.)
2. Remove the desired knockouts
from the back of the heater casing.
3. Complete the thermostat—and
other optional accessory—wiring
using the installation instructions
provided with them.
4. Using the appropriate unit wiring
diagram as a guide, complete the
electrical supply wire connections
and attach the ground wire.
Note: Since horizontal air discharge
units are designed to be swiveled to
direct the discharge air as needed,
be sure to provide flexible electrical
connections at the unit.
5. Close the unit access panel; then
provide supply power to the unit,
and adjust the thermostat and any
accessories for proper operation.
Note: Certain unit heater models can
be converted from single to
three-phase electrical service (see
Table 2). Refer to the appropriate unit
wiring diagram for specific conversion
instructions. Units that carry a
dual-voltage rating (B) require specific
wiring changes when converting from
240 to 208-volt service. Follow the
instructions on the unit wiring diagram
carefully.
Net Junction Box Volume
KW Cubic Inches CC
3.3 -5 74.4 1219
7..5 - 10 198 3245
15.0 - 20 198 3245
25.0 - 50 341 5592
* Use 75° C wire.
**Use copper conductors on all heaters.
Installation
+ Amp rating for 3-phase operation
1 KW = 3,413 BTU
14 UHEC-IM-7A

Installation
Unit
Model Number Capacity Element and Motor
Voltage Element Phase
Std.
Control
Voltage
Max.
Amp
Rating
Min.
Circuit
Fuse Size
Supply
Wire Gauge
(60° C)**
Kw
Rating BTU/Hr (000)
UHEC-031A0C0 3.3 11.2 208 1 208 15.9 20A 12GA
UHEC-031B0C0 3.3/2.5 11.2/8.5 240/208 1 240/208 13.7/11.9 20A/15A 12GA/14GA
UHEC-031AACA 3.3 11.2 208 1 24 15.9 20A 12GA
UHEC-032A0C0 3.3 11.2 208 1-3 208 15.9 20A 12GA
9.2 + 15A 14GA
UHEC-032B0C0 3.3/2.5 11.2/8.5 240/208 1-3 240/208 13.7/11.9 20A/15A 12GA/14GA
7.9/6.9 + 10A/10A 14GA/14GA
UHEC-031C0C0 3.3 11.2 277 1 277 11.9 15A 14GA
UHEC-031CACA 3.3 11.2 277 1 24 11.9 15A 14GA
UHEC-033DACA 3.3 11.2 480 3 24 4.0 15A 14GA
UHEC-031BACA 3.3/2.5 11.2/8.5 240/208 1 24 13.7/11.9 20A/15A 12GA/14GA
UHEC-032AACA 3.3 11.2 208 1-3 24 15.9 20A 12GA
9.2 + 15A 14GA
UHEC-032BACA 3.3/2.5 11.2/8.5 240/208 1-3 24 13.7/11.9 20A/15A 12GA/14GA
7.9/6.9 + 10A/10A 14GA/14GA
UHEC-051A0C0 5.0 17.1 208 1 208 24.1 35A 8GA
UHEC-052AACA 5.0 17.1 208 1-3 24 24.1 35A 8GA
13.9 + 20A 12GA
UHEC-051B0C0 5.0/3.7 17.1/12.8 240/208 1 240/208 20.9/18.1 30A/25A 10GA/10GA
UHEC-052A0C0 5.0 17.1 208 1-3 208 24.1 35A 8GA
13.9 + 20A 12GA
UHEC-052B0C0 5.0/3.7 17.1/12.8 240/208 1-3 240/208 20.9/18.1 30A/25A 10GA/10GA
12.1/10.4 + 20A/15A 12GA/14GA
UHEC-052BACA 5.0/3.7 17.1/12.8 240/208 1-3 24 20.9/18.1 30A/25A 10GA/10GA
12.1/10.4 + 20A/15A 12GA/14GA
UHEC-051C0C0 5.0 17.1 277 1 277 18.1 25A 10GA
UHEC-053DACA 5.0 17.1 480 3 24 6.1 15A 14GA
UHEC-051AACA 5.0 17.1 208 1 24 24.1 35A 8GA
UHEC-051BACA 5.0/3.7 17.1/12.8 240/208 1 24 20.9/18.1 30A/25A 10GA/10GA
UHEC-051CACA 5.0 17.1 277 1 24 18.1 25A 10GA
UHEC-072AACA 7.5 25.6 208 1-3 24 36.1 50A 6GA
20.8 + 30A 10GA
UHEC-072BACA 7.5/5.6 25.6/19.2 240/208 1-3 24 31.3/27.1 40A/35A 8GA/8GA
18.1/15.6 + 25A/20A 10GA/12GA
UHEC-071CACA 7.5 25.6 277 1 24 27.1 35A 8GA
UHEC-073DACA 7.5 25.6 480 3 24 9.1 15A 14GA
UHEC-102AACA 10.0 34.1 208 1-3 24 47.8 60A 4GA
27.8 + 35A 8GA
Table 3 Electrical Data
UHEC-102BACA 10.0/7.5 34.1/25.6 240/208 1-3 24 41.6/36.1 60A/50A 4GA/6GA
24/20.8 + 30A/30A 8GA/10GA
UHEC-101CACA 10.0 34.1 277 1 24 36.1 50A 6GA
UHEC-103DACA 10.0 34.1 480 3 24 12.1 20A 12GA
UHEC-153AACA 15.0 51.2 208 3 24 41.7 60A 4GA
UHEC-153BACA 15.0/11.2 51.2/38.4 240/208 3 24 36.1/31.3 50A/40A 6GA/8GA
UHEC-153DACA 15.0 51.2 480 3 24 18.1 25A 10GA
UHEC-203BACA 19.7/14.8 67.2/50.5 240/208 3 24 47.8/41.1 60A/60A 4GA/6GA
UHEC-203DACA 20.0 68.3 480 3 24 24.1 35A 8GA
UHEC-253AACA 25.0 85.3 208 3 24 69.5 90A 2GA
UHEC-253BACA 25.0/18.7 85.3/64.0 240/208 3 24 60.2/52.1 80A/70A 3GA/4GA
UHEC-253DACA 25.0 85.3 480 3 24 30.1 40A 8GA
UHEC-303AACA 30.0 102.4 208 3 24 83.4 110A 2GA*
UHEC-303BACA 30.0/22.5 102.4/76.8 240/208 3 24 72.3/62.5 100A/80A 2GA/3GA
UHEC-303DACA 30.0 102.4 480 3 24 36.2 50A 6GA
UHEC-403AACA 40.0 136.5 208 3 24 111.2 150A 1/0GA*
UHEC-403BACA 40.0/30.0 135.4/102.4 240/208 3 24 96.4/83.4 125A/110A 1GA*/2GA*
UHEC-403DACA 39.0 133.1 480 3 24 47.0 60A 4GA
UHEC-503AACA 50.0 170.6 208 3 24 139.0 175A 2/0GA *
UHEC-503BACA 50.0/37.5 170.6/128.0 240/208 3 24 120.5/104.3 175A/150A 2/0GA*/1/0GA*
UHEC-503DACA 50.0 170.6 480 3 24 60.3 80A 3GA
UHEC-IM-7A 15

WARNING!
Always disconnect unit heater from
power supply before attempting to
service, clean, or disassemble any
component from the unit. Failure to
do so may result in injury or death
due to electrical shock.
Electrical Circuitry
Inspect the control panel wiring once
each year to ensure that the insulation
is intact, and that all connections are
tight. Be sure to examine all heater
and relay contacts as well; if the
contacts appear badly pitted or
burned, replace the contactor/relay.
Note: To protect electrical circuits
during operation, use only the correct
size of over current protection; see
Table 2.
Cleaning
Clean the unit casing, fan and motor
on an annual basis. (A dirty motor
may run hot and will eventually be
damaged internally.) Clean and
repaint any rust spots on the casing.
Lubrication
All unit heaters with ratings of up to 20
Kw are equipped with permanently
lubricated fan motors, so only
occasional cleaning is required. Unit
heaters with ratings above 20 Kw
have fan motors factory-lubricated to
provide 5 years of continuous service,
or 10 years of intermittent operation.
If lubrication is desired, remove the oil
access plug on the back of the unit at
the motor intake grille. Then, open the
oil cap and add SAE No. 10
non-detergent electric motor oil.
Replace the cap and plug.
Note: Except in emergencies, do not
open the air disconnect while the
heater is in operation. Any power
interrupt during normal heater
operation will prevent the fan from
running; residual heat remaining in the
unit may cause the thermal cutouts to
open.
Maintenance
16 UHEC-IM-7A

The following troubleshooting chart is
provided to serve as an aid for
identifying the cause of any system
malfunctions that may occur. Within
each chart are three columns: (1) the
Symptom column describes the
behavior the unit is exhibiting; (2) the
Probable Cause column identifies the
most likely sources of the malfunction;
and (3) the Recommended Action
column describes the suggested
action for correcting the problem.
Note: Use this troubleshooting chart
only as a guide for determining the
cause of mechanical failure or
malfunction. When mechanical
problems do occur, the Trane
Company recommends that qualified
service personnel be contacted to
help ensure proper diagnosis and
repair of the unit.
WARNING!
To avoid injury or death due to
electrical shock or entanglement
with moving parts, never open
access panel(s) to inspect or
service unit without first opening
unit disconnect switch.
Trouble Analysis
Symptom Probable Cause Recommended Action
Thermostat calls for heat, but unit
does not function.Blown Fuse Replace fuse; see Table 2 for proper size. Determine cause for blown fuse.
Incorrect wiring Check wiring connnections against
wiring diagram.
Thermal cutout open, causing heater
element and control circuit to
de-energize.
Check for the following:
a. Correct supply volts and phase.
b. Correct control wiring (i.e. heater
control must be thru thermostat
control wiring section only).
c. Power interruption to heater during
heater operation.
d. Restriction of air around heater.
e. 1 to 5-minute fan purge after
thermostat is satisfied (off).
Fan motor runs “hot”. Dust or dirt accumulation on fan motor. Clean fan motor and casing.
Dirt accumulation on louvers and
heating elements. Clean louvers and between heating elements.
Motor needs lubrication. See Maintenance section of this
manual.
Fan motor runs, but there is no heat. Element contactor is not operating
correctly. Check wiring for open circuits. Replace contactor if defective.
Element fuse blown. Determine cause of blown fuse and
replace fuse. See Table 2 for fuse
sizes.
UHEC-IM-7A 17

Caution:
Use copper conductors only to
prevent equipment damage.
Figure 6 Typical wiring for Models UHEC
031A0C0, 031B0C0, 031C0C0,
051A0C0, 051B0C0 and 051C0C0
WARNING!
Disconnect electrical power
source to prevent injury or death
from electrical shock.
- - - - Field-Installed wiring
* Optional
Notes:
1. For 2 pole thermostat, remove 1 to 8 jumper. For 1 pole
thermostat jumper 1 to 8, wire thermostat 4 to 5.
2. Control circuit wiring must be NEC class 1, rated 600 volts.
WD5101
Wiring Diagrams
18 UHEC-IM-7A

Use copper conductors only to prevent equipment damage. Figure 7 Typical wiring for Models UHEC 031AACA, 051AACA, 031CACA, 051CACA, 071CACA and 101CACA Disconnect electrical power source to prevent injury or death from electrical shock. ——- Field-Installed wiring
* Optional Notes: Control circuit wiring must be NEC class 1, rated 600 volts.
WD5104
Wiring Diagrams
UHEC-IM-7A 19

Use copper conductors only to prevent equipment damage.
Figure 8 Typical wiring for Models UHEC 032AACAand 052AACA
Disconnect electrical power source to prevent injury or death from electrical shock.
WD5109
——- Field-Installed wiring
* Optional Notes: 1. For conversion from single-phase to 3-phase power supply (L1, L2 and L3), move Wire A1 from L2 to L3, and move Wire A2 from L1 to 10. 2. Control circuit wiring must be NEC class 1, rated 600 volts.
Wiring Diagrams
20 UHEC-IM-7A