A.O. Smith T-H2-DV User manual

T-H2-DV/T-H2-OS Service Manual
Ver. 1.01
1
CONFIDENTIAL
   
T-H2-DV/ T-H2-OS
On-Demand Water Heater
Service Manual
Flash Water Heater
Model T-H2-DV
Flash Water Heater
Model T-H2-OS
A.O. Smith Water Products Company
500 Tennessee Waltz Parkway
Ashland City, TN 37015
Toll Free: 1
-
877
-
737
-
284
0

T-H2-DV/T-H2-OS Service Manual
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Table of Contents
1.
Specifications…………………………………………………..…………………………………………………..……
3
2.
Exterior view……………………...…….……………………………………………………………………………….
4
3.
Interior view…………………………….………………………………………………………………………………..
6
4.
List of main components in the interior view…….………………………………………………….……
8
5.
Schematic diagram…………………………………………………………………………………………………....
11
6.
Wiring diagram………………………………………………………………………………………………………….
12
7.
Wiring diagramcheckpoints for diagnosis………………………..………………….………………….…
13
8.
8.
(A) Resistance valuesof the temperature thermistors……..…………………………………………
(B) Resistance valuesof the temperature Exhaust thermistors…………………………………..
15
16
9.
Operationalflowchart…………………………………………………………………………………………….…
17
10.
Componentspecifications………………...…………………………………………………………………….…
18
11.
FaultAnalysis &Specifications…………………………………………………………………………………. 42
12.
Controls and settings……………………………………………………………………………………………….…
55
13.
Components diagrams………………………………………………………………..................................
90
14.
Parts list……………………………………………………………………………………………………………………..
93
15.
Revisions……………………………………………………...…………………………………………………………...
99

T-H2-DV/T-H2-OS Service Manual
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CONFIDENTIAL
1. Specifications
Model T-H2-DV T-H2-OS
Dimensions H25.6"×W18.5"×D12.4"
Weight 73 lbs. 71 lbs.
Combustion
INPUT
BTU/h Max 199,000
Min 13,000
Combustion System
Power vent
Installation Direct-vent Outdoor
Fan motor PWMturbo fan
Manifold
Pressure*
Max
LP 4.9” WC
Natural 3.6” WC LP 4.6” WC Natural 2.8” WC
Min
LP 1.0” WC
Natural 0.7” WC LP 0.9” WC Natural 0.6” WC
Water control
Flow rate 0.5 GPMto 9.0 GPM
Available set
temperatures 100°F to 185°F default: 120°F
Temperatureon
the unitsettings 100°F, 105°F, 110°F,115°F, 120°F, 125°F, 135°F, 140°F, 145°F, 150°F, 155°F, 160°F, 165°F, 170°F, 175°F,185°F
Bypass valve Yes
Thermistors 4 thermistors
(In, Out, Mixing, Exhaust) 3 thermistors (In, Out, Mixing)
Operation
Remote controller
model TM-RE30
PCB model T-H2
Indicators Red LEDon PCB duringoperation & 3-digit 7-SEG LED
Power supply
control Surge absorber & PowerON-OFF switch
Features
Freeze protection
Ceramicheatersand Auto-firing system
Self
-
combustion
improvement
Air-Fuel Ratio Detection System
Easy-Link system
Yes (Up to 4 units)
Multiple-system N/A
*The manifold pressure measurement is baseon conditions without front cover.

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2. Exterior view
Top view Bottom view
Sideview
Front view
T-H2-DV
GAS 4-5/8" (116.8mm)
120VAC 2-1/4" (58.2mm)
HOT 5-1/2" (142.2mm)
GAS 6" (153.6mm)
HOT 7-1/4" (182.1mm)
120VAC 8-1/2" (216.3mm) COLD 8-5/8" (220.6mm)
COLD 1-1/4" (29.2mm)
18-1/2" (470mm)
7-1/4" (183.8mm)
6-3/8" (161.5mm)
18-1/2" (470mm)
6-1/4" (161.5mm)
3-1/2" (90mm)
12-1/2" (320mm)
1/2" (12.5mm)
GAS 6" (153.6mm)
HOT 7-1/4" (182.1mm)
COLD 8-5/8" (220.6mm) HOT 5-5/8" (142.2mm)
120VAC 8-1/2" (216.3mm)
10-1/2" (266.8mm)
6-1/4" (159.1mm)
2-3/4" (69.1mm) INTAKE
2-3/4" (71.8mm)EXHAUST
12-1/2" (316mm)
25-1/2" (649mm)
120VAC 2-1/4" (58.2mm) 4-5/8" (116.8mm) GAS
Male 4" (100.8mm) 4" (102mm) Female
3/4" (18.8mm)
Condensate drain port
Condensate drain port
29-1/2" (751mm)
1-1/4" (29.2mm) COLD
6-5/8" (168.4mm)

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Side view Frontview
Bottom view
Top view
T-H2-OS
18-1/2" (470mm)
GAS 6" (153.6mm)
COLD 8-5/8" (220.6mm)
HOT 7-1/4" (182.1mm)
120VAC 8-1/2" (216.3mm)
COLD 1-1/4" (29.2mm)120VAC 2-1/4" (58.2mm)
GAS 4-5/8" (116.8mm)HOT 5-1/2" (142.2mm)
25-1/2" (649mm)
1/2" (12.5mm)
GAS 6" (153.6mm)
HOT 7-1/4" (182.1mm)
COLD 8-5/8" (220.6mm)
18-1/2" (470mm)
3-1/2" (90mm)
12-1/2" (320mm)
4-1/2" (115mm)
4-1/2" (115mm)
4-5/8" (116.8mm) GAS120VAC 2-1/4" (58.2mm)
HOT 5-5/8" (142.2mm)
12-1/2" (316mm)
120VAC 8-1/2" (216.3mm)
10-1/2" (266.8mm)
6-1/4" (159.1mm)
Condensate drain port
Condensate drain port
29-1/2" (751mm)
1-1/4" (29.2mm) COLD

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3. Interior view
T-H2-DV
20
32
16
10
18
24
11
15
3
19
37
38
17
33
58
27
6
7
21
23
30
31
9
1
13
25
2
22
4
12
14
28
29 26
26
35
35
34
36

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T-H2-OS
1
3
4
56 27
7
8
9
2
11
13
15
16
17
19
20
21
22
23 24
25
29
28
10
12
33 37
38
26
18
35
34
35
26
14
36

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4. List of main components in the interior view
No.
Description Item# in components
diagram
Takagi
Part # Common parts Forothermodels
1 Manifold assemblywith gas
valve assembly 118 EKH6T (LP model)
T-K4-IN/OS, T-D2-IN/OS
EKH6U (NA model)
2 Computerboard 701 EKH4E
3 Igniter 123 EKN74 T-K3, T-K3-Pro, T-K3-SP/OS, T-KJr2-IN/OS, T-K4-IN/OS,
T-D2-IN/OS, T-M50,T-M32
4 Transformer 702 EM296 T-M50
5 Waterinlet 411 EM404 T-M32
6 Water outlet 435 EKJ02 T-M32
7 Mixing thermistor 418 EX00H T-M32
8 Inletthermistor 422 EKK38 T-K3, T-K3-Pro, T-D2-IN/OS,
T-M50, T-M32
9 Output thermistor 433 EKK2T T-K3, T-K3-Pro,T-D2-IN/OS,
T-M50, T-M32
10
Overheatcut-off fuse 404 EX02A
11
Burner assembly (Burners) 101 EKH5W T-K4-IN/OS, T-D2-IN/OS
12
Hi-limit switch 432 EKN34 T-K3, T-K3-Pro, T-K3-SP/OS,
T-D2-IN/OS, T-M50,T-M32
13
Fan motor 114 EKK25 T-K3, T-K3-Pro,T-K3-SP, T-K4-IN, T-D2-IN, T-M50,
T-M32
14
Freeze protection
thermostat
704 EKH79 (T-H2-DV)
719 EKH7A (T-H2-OS)
15
Flow sensor 429 EKH33 T-M50, T-M32
16
Primary heat exchanger
assembly
401 EKH5P (T-H2-DV)
456 EKH63 (T-H2-OS)

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No.
Description Item# in components
diagram
Takagi
Part # Common parts Forothermodels
17
Gas inlet 121 EKK1E T-K3, T-K3-Pro, T-K3-SP/OS, T-KJr2-IN/OS, T-K4-IN/OS,
T-D2-IN/OS
18
Pipe heater 426 EKJ47
19
Water control valve 423 EKH32 T-M50, T-M32
20
Secondary heat exchanger 446 EKH6X
21
Outlet drain plug 416 EK239 T-M32
22
AFR rod 106 EKK0E T-K3, T-K3-Pro, T-K3-SP/OS, T-K4-IN/OS, T-D2-IN/OS,
T-M50, T-M32
23
Flame rod 106 EKK0E T-K3, T-K3-Pro, T-K3-SP/OS, T-K4-IN/OS, T-D2-IN/OS,
T-M50, T-M32
24
Igniterrod 108 EKK0F T-K3, T-K3-Pro, T-K3-SP/OS, T-K4-IN/OS, T-D2-IN/OS,
T-M50, T-M32
25
Fuse box 715 EKH67
26
Heater 101 405 EX002 T-M50, T-M32
27
Outlet heater 415 EKK2P T-K3, T-K3-Pro, T-K3-SP/OS, T-KJr2-IN/OS, T-K4-IN/OS,
T-D2-IN/OS, T-M32
28
Over heatcutoff fuse for
combustion chamber 008 EM484 T-M32
29
Secondary heat exchanger
drain plug 458 EX13A
30
Fan motorfor exhaust 124 EKH5T
31
Hi-limit switch forexhaust 442 EKH6G

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No.
Description Item# in components
diagram
Takagi
Part # Common parts Forothermodels
32
Exhaustthermistorassembly
706 EKH6E
33
Inlet drain plug (water filter)
409 EX006 T-M50, T-M32
34
Flat heater 453 EX13P
35
3 array heater 454 EX13R
36
Case assembly 001 EKH5B (T-H2-DV)
015 EKH5C (T-H2-OS)
37
Manifold port N/A N/A
38
Gas inlet port N/A N/A