A.O. Smith T-H3J-DV User manual

A.O. Smith Water Products
Company
500 Tennessee Waltz Parkway
Ashland City, TN 37015
Toll Free: 1-877-737-2840
240 (T-H3J), 340 (T-H3S)
and 540 (T-H3) Models
On-Demand Water Heater
Service Manual

2Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
Table of Contents
1. Specifications....................................................................................................................
2. Exterior view.....................................................................................................................
3. Interior view.......................................................................................................................
4. List of main components in the interior view...................................................................
5. Schemac diagram............................................................................................................
6. Wiring diagram.................................................................................................................
7. Wiring diagram checkpoints for diagnosis........................................................................
8. (A) Resistance values of the temperature thermistors.....................................................
8. (B) Resistance values of the temperature exhaust thermistors........................................
9. Operaonal ow chart......................................................................................................
10. Component specicaons................................................................................................
11. Fault Analysis & Specicaons.........................................................................................
12. Controls and sengs........................................................................................................
13. Components diagrams......................................................................................................
14. Parts list............................................................................................................................
15. Revisions...........................................................................................................................
3
4
6
10
13
14
16
18
19
20
21
47
58
89
93
104

3Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
1. Specifications
Model 240
Indoor
(T-H3J-DV)
240
Outdoor
(T-H3J-OS)
340
Indoor
(T-H3S-DV)
340
Outdoor
(T-H3S-OS)
540
Indoor
(T-H3-DV)
540
Outdoor
(T-H3-OS)
Dimensions inch H 22.4 x W 17.7 x D 10.7
570 (H) x 450 (W) x 272 (D)
mm
Weight lbs. (kg) 58 (26.3) 58 (26.2) 58 (26.3) 58 (26.2) 58 (26.8) 58 (26.9)
Combustion
INPUT
BTU/h
Max 160,000 180,000 199,000
Min Propane 13,000
Natural gas 15,000
Combustion
system
Installation
Power vent
Installation Direct-vent
Indoor Outdoor Direct-vent Indoor Outdoor Direct-vent Indoor Outdoor
Fan motor PWM turbo fan
Manifold
Pressure*
("W.C.)
Max Propane 2.2
Natural 1.9
Propane 2.2
Natural 2.0
Propane 2.6
Natural 2.4
Propane 2.7
Natural 2.4
Propane 3.2
Natural 2.8
Propane 3.2
Natural 2.9
Min Propane 0.6
Natural 0.7
Propane 0.7
Natural 0.7
Propane 0.6
Natural 0.7
Propane 0.7
Natural 0.7
Propane 0.6
Natural 0.7
Propane 0.7
Natural 0.7
Water control
Flow rate GPM 0.5 to 6.6 0.5 to 8.0 0.5 to 10.0
Available
set
temperatures
°F
(°C)
100 to 140 (38 to 60)
default: 120 (49)
100 to 185 (38 to 85)
default: 120 (49)
Temperature
DIPswitch
settings
°F
(°C) 120 (49), 140 (60)
Bypass valve N/A Yes
Thermistors 2 thermistors (In, Out) 3 thermistors
(In, Out, Heat exchanger)
Operation
Temperature
control
Temperature controller : Direct Vent Indoor models
Temperature remote controller (TM-RE40) : Outdoor models
PCB model 240
Part # 319143-543 (EK186)
340
Part # 319143-544 (EK175)
540
Part # 319143-545 (EK176)
Indicators Stand-by LED
Power supply
control Surge absorber & Power ON-OFF switch
Features
Freeze
protection
Ceramic heaters (All models) and
Auto-firing system (Only 540 Direct Vent Indoor models (T-H3-DV) models)
Self-
combustion
improvement
Air-Fuel Ratio Detection System
Easy-Link
system N/A Yes (Up to 4 units)
Multiple-
system N/A Yes (Up to 20 units)
*The manifold pressure measurement is based on conditions without front cover.

4Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
2. Exterior view
Direct Vnet Indoor models
Side view
Front view
7-7/8" (199 mm)
GAS 5-1/8" (131 mm)
COLD 6-3/4" (172 mm)
HOT 5-1/2" (140 mm)
7-1/2" (189 mm)
GAS 5-7/8" (147 mm)
Condensate drain port
COLD 5/8" (17 mm)
HOT 4-3/4" (120 mm)
17-5/8" (448 mm)
6-1/4" (159 mm)
5-3/4" (147 mm)
120 VAC 3" (77 mm)
120 VAC 6-7/8" (174 mm)
∅
Drain port
Female
10-3/4" (272mm)
22-1/22" (570 mm)
Condensate drain port
4" (102 mm)
2-5/8" (68 mm)
Exhaust
Intake
Female
∅
7-7/8" (199 mm)
7-1/2" (189 mm)
7" (180 mm) 4" (101 mm)
17-3/4" (450 mm)
HOT 4-3/4" (120 mm)
6-3/4" (170 mm)
COLD 5/8" (17 mm)
GAS 5-3/4" (147 mm)
Condensate drain port
23-5/8" (600 mm)
2-5/8" (65 mm)
5-3/4" (147 mm)
11-1/4" (285 mm)
1/2 (13 mm)
GAS 5-1/8" (131 mm)
HOT 5-1/2" (140 mm)
COLD 6-3/4" (172 mm)
Condensate drain port
6-1/4" (159mm)
4" (102 mm)
24-7/8" (631 mm)
120 VAC 3" (77 mm)
Drain port 6" (152 mm)
120 VAC 6-7/8" (174 mm)
Bottom view Top view

5Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
Outdoor models
Side view
Front view
17-5/8" (448 mm)
6-1/4" (159 mm) COLD 5/8" (17 mm)
120 VAC 3" (77 mm)
HOT 5-1/2" (140 mm)
HOT 4-3/4" (120 mm) 7-1/2" (189 mm)
Condensate drain port
GAS 5-1/8" (131 mm)
COLD 6-3/4" (172 mm)
7-7/8" (199 mm)
Drain port
7-1/2" (189 mm)
10-3/4" (272 mm)
22-1/2" (570 mm)
120 VAC
Condensate drain port
7-7/8" (199 mm)
Condensate drain port
11" (281 mm)
1/2" (13 mm)
120 VAC 3" (77 mm)
GAS (131 mm)
HOT (140 mm)
COLD 6-3/4" (172 mm)
Condensate drain port
COLD 5/8" (17 mm)
GAS 5-3/4" (147 mm)
HOT 4-3/4" (120 mm)
6-3/4" (170 mm)
1-1/2" (37 mm)
11-1/4" (285 mm)
120 VAC 6-1/4" (159 mm)
17-3/4" (450 mm)
7" (180 mm)
23-5/8" (600 mm)
24-7/8" (631 mm)
3-5/8" (92 mm)
4-1/2" (114 mm)
Drain port 6" (152 mm)
Bottom view Top view

6Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
3. Interior view
240 Indoor (T-H3J-DV)
340 Indoor (T-H3S-DV)
1
2
3
4
5
6
79
10
11
12
13
14
15
16
18
19
20
21
22
23
24
26
28
27
29
30
31
31
33
33
17
33
37
38
34
39
32
32
REMOTE
CONTROLLER
OFF ON
AC120V
8
25

7Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
240 Outdoor (T-H3J-OS)
340 Outdoor (T-H3S-OS)
1
2
3
4
5
6
78
9
10
11
12
13
14
15
16
18
19
20
21
22
23
24
25
26
28
27
29
35
30
31
31
33
33 17
34
39
32
32
REMOTE
CONTROLLER
OFF ON
AC120V

8Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
540 Indoor (T-H3-DV)
1
2
3
4
5
6
78
9
10
11
12
13
14
15
16
18
19
20
21
22
23 24
25
26
28
27
29
35
30
31
31
33
33 17
33
36
37
38
34
39
32
32
AC120V
REMOTE
CONTROLLER
OFF ON

9Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
540 Outdoor (T-H3-OS)
1
2
3
4
5
6
78 9
10
11
12
13
14
15
16
18
19
20
21
22
23
24
25
26
28
27
29
35
30
31
31
33
33
17
36
34
39
32
32
REMOTE
CONTROLLER
AC120V
OFF ON

10 Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
4. List of main components in the interior view
No. Description
Items# in
components
diagram
Part #
240, 340 and
540 models
T-H3J, T-H3S and
T-H3 models
1. Case assembly
Indoor
models 001
N/A EK159
Outdoor
models N/A EK164
2.
Manifold
assembly with
gas valve
assembly
LP model
102
319143-515 EK181
NA model 319143-516 EK182
3. Computer board 701
319143-543
(240 models)
EK186
(T-H3J models)
319143-544
(340 models)
EK175
(T-H3S models)
319143-545
(540 models)
EK176
(T-H3 models)
4. Igniter 711 319143-479 EK153
5. Gas valve
assembly
LP model Included in
#102
319143-515 EK181
NA model 319143-516 EK182
6. Water inlet 404 319143-193 EKK1U
7. Water outlet 409 319143-530 EK208
8. Inlet thermistor 407
319143-214
(240/340 models)
EKK4J
(T-H3J/T-H3S models)
319143-465
(540 models)
EK137
(T-H3 models)
9. Outlet thermistor 408
319143-529
(240/340 models)
EK207
(T-H3J/T-H3S models)
319143-190
(540 models)
EKK1A
(T-H3 models)
10. Overheat cut-off fuse 413 319143-149 EK333
11. Burner assembly 101 319143-514 EK192
12. Hi-limit switch 412
319143-228
(240/340 models)
EM212
(T-H3J/T-H3S models)
319143-095
(540 models)
EKN34
(T-H3 models)