A.O. Smith 110 User manual

110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
1
CONFIDENTIA
L
110 Direct Vent Indoor
and Outdoor Models
On-Demand Water Heater
Service Manual
110 Indoor
A.O. Smith Water Products Company
500 Tennessee Waltz Parkway
Ashland City,TN 37015
Toll Free: 1
-
877
-
73
7
-
2840
110 Outdoor

110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
2
CONFIDENTIA
L
Table of Contents
1.
Specifications………………………………………...…...………….……………………...…………………………
3
2.
Exterior view……………………...…….……………………………………………………………………………....
4
3.
Interior view…………………………….………………………………………………………………………………..
6
4.
Listof main components in the interior view…….……………………………………………………….
8
5.
Schematic diagram…………………………………………………………………………………………………….
10
6.
Wiring diagram………………………………………………………………………………………………………….
11
7.
Wiring diagram checkpoints for diagnosis………………………..………………….….…………………
12
8.
Resistance values of the temperature thermistors…………..…………………………………………
14
9.
Operational flow chart……………………………………………………………………………………………….
15
10.
Component specifications………………...……………………………………………………………………….
16
11.
FaultAnalysis &Specifications……………………………………………………………........................
35
12.
Controls and settings………………………………………………………………………………………………….
44
13.
Components diagrams………………………………………………………………..................................
58
14.
Parts list……………………………………………………………………………………………………………………..
61
15.
Revisions……………………………………………………...……………………………………………………………
65

110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
3
CONFIDENTIA
L
1. Specifications of the 110 Direct Vent Indoor* and 110 Outdoor
Model 110 Indoor 110 Outdoor
Dimensions H20.5"×W13.8"×D6.7"
Weight 33 lbs.
Combustion
INPUT
BTU/h Max 140,000
Min 19,500
Combustion System
Power vent
Installation Indoor & Direct-vent Outdoor
Fan motor PWM Multi blade fan
Manifold
Pressure**
Max
LP 2.6” WC
Natural 2.2” WC LP 3.0” WC Natural 2.7” WC
Min
LP 0.7” WC
Natural 0.6” WC LP 0.8” WC Natural 0.7” WC
Water control
Flow rate 0.75 to 6.6 GPM
Available set
temperatures 99°F to 167°F Default:122°F
Temperature
dipswitch settings
113°F, 122°F, 131°F, 140°F
Bypass valve N/A
Thermistors 2 thermistors (In, Out)
Operation
Remote controller
model 9007666005
PCB model 110
Indicators Red LED on PCB during operation
Powersupply
control Surge absorber and Power ON-OFF switch
Features
Freezeprotection
Ceramic heaters
Self-combustion
improvement Air-Fuel Ratio Detection System
Easy-Link system
N/A
Multiple-system
N/A
* The 310 DirectVent Indoor means the 110 Indoor in the text.
**The manifold pressure measurement is base on conditionswithout front cover.

110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
4
CONFIDENTIA
L
13-3/4" (350mm)
10" (254mm)
2-1/4" (56mm)
21-3/8" (544mm) 20-1/4" (520mm)
2-1/4" (56 mm) COLD
3-7/8" (98mm) GAS
4-7/8" (124mm) HOT
1" (26mm)
4" (102mm)
4-7/8" (123mm) 120 VAC
7-3/4" (196mm)
1-3/4" (45mm)1-3/4" (45mm)
1-7/8" (47mm)
COLD 3-1/8" (79mm)
HOT 5-1/4" (133mm)
120 VAC 1-3/8" (36mm)
GAS 4-7/8" (124mm)
2-1/4" (57mm)
13-1/8" (334mm)
6-1/4" (160mm)
1" (102mm)
COLD 2-1/4" (56mm)
HOT 4-7/8" (124mm)
HOT 5-1/4" (133mm) GAS 4-7/8" (124mm)
120 VAC 1-3/8" (36mm)
GAS 3-7/8" (98mm)
120VAC 4-7/8" (123mm)
COLD 3-1/8" (79mm)
2. Exterior view
110 Indoor
Side view
Front view
Top view
Bottom view

110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
5
CONFIDENTIA
L
13-3/4" (350mm)
10" (254mm)
21-3/8" (544mm) 20-1/4" (520mm)
2-1/4" (56 mm) COLD
3-7/8" (98mm) GAS
4-7/8" (124mm) HOT
1" (26mm)
4-7/8" (123mm) 120 VAC
7-3/4" (196mm)
1-3/4" (45mm)1-3/4" (45mm)
1-7/8" (47mm)
COLD 3-1/8" (79mm)
HOT 5-1/4" (133mm)
120 VAC 1-3/8" (36mm)
GAS 4-7/8" (124mm)
13-1/8" (334mm)
COLD 2-1/4" (56mm)
HOT 4-7/8" (124mm)
HOT 5-1/4" (133mm) GAS 4-7/8" (124mm)
120 VAC 1-3/8" (36mm)
GAS 3-7/8" (98mm)
120V 4-7/8" (123mm)
7-7/8" (203mm)
1-5/8" (43mm)
COLD 3-1/8" (79mm)
110 Outdoor
Side view
Front view
Top view
Bottom view

110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
6
CONFIDENTIA
L
3. Interior view
110 Indoor
1
10
11
24
2
4
28
27
29
17
13
148256
7
9
3
5
20
26
22
23
18
12
16
19
15
30

110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
7
CONFIDENTIA
L
110 Outdoor
1
10
11
24
2
4
28
27
29
17
13
14825
6
7
9
3
5
20
26
22
23
18
12
16
19
15
30

110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
8
CONFIDENTIA
L
4. List of main components in the interior view
No.
Description Item# in components
diagram
AOS
Part# Common parts for other models
1 Case assembly 001
319143-159
(110 Indoor)
319143-172
(110 Outdoor)
2Manifold assembly with
gas valve assembly 102 319143-169 (LP model)
319143-165 (NA model)
3 Computerboard 701 319143-164
4 Igniter 711 319143-052 520, 310,510, 910, 710
5 Transformer 702 319143-182 310, 510
6 Water inlet 404 319143-193 310,510
7 Wateroutlet 409 319143-194 310,510
8 Inlet thermistor 407 319143-214 310
9 Outletthermistor 408 319143-218 310
10
Overheat cut-off fuse 413 319143-149 310,510, 910
11
Burnerassembly (Burners)
101 319143-161
12
Hi-limitswitch 412 319143-228 310
13
Fan motor 103 319143-347
14
Freeze protection
thermostat
713 319143-185 310,510, 710
710 319143-210 310,510
15
Flow sensor 402 319143-167 310
16
Heatexchanger assembly
401
319143-162
(110 Indoor)
319143-166
(110 Outdoor)
17
Gas inlet 118 319143-050 520, 310, 510
18
Heater 414 319143-200 310,510
19
Flow adjustment valve 402 319143-167 310

110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
9
CONFIDENTIA
L
No.
Description Item# in components
diagram
AOS
Part# Common parts Forother models
20
Surge box 703 319143-168 310,510
21
Outletdrain plug 410 319143-199 310,510, 910
22
Air-fuel ratio rod (AFR rod)
108 319143-339
23
Flame rod 108 319143-339
24
Igniter rod 109 319143-373
25
Inlet drain plug
(water filter) 405 319143-197 310,510
26
120 VAC
PowerON-OFF switch 706 319143-141 520, 310, 510
27
Gas valve assembly 102 319143-169 (LP model)
319143-165 (NA model)
28
Manifold port N/A N/A
29
Gas inletport N/A N/A
30
Exhaustchamber Included in
401
319143-162
(110 Indoor)
319143-166
(110 Outdoor)

110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
10
CONFIDENTIA
L
5. Schematic diagram
The diagram below refers to both the 110 Indoorand 110 Outdoor.
1. When a hot water tap is opened,cold water enters the 110 Indoor or 110 Outdoor.
2. The water flow sensor detects this water flowand sends this information tocomputer.
3. The computer initiates fan motorand sends signal to igniterto create ignition spark.
4. The main, proportional, and solenoid gas valves open to allow gas input.
5. The gas ignitesand flames appear inside the burner chamber.
6. Water circulates through the heat exchanger and is heated up to the settemperature.
7. Using thermistors to measure temperatures, the computer modulates the gas and water valves to
ensureproperoutputwatertemperatures.
8. When the tap is closed, the 110 Indoor or 110 Outdoor shutsdown.
H
O
T
C
O
L
D
G
A
S
Hi-limit SW
Inlet drain
plug filter
Outlet
Thermistor
Drain plug
Main gas valve
Gas solenoid valve 2
Fan motor
Flame rod
Igniter rod
Igniter
O.H.C.F
Heater
Flow adjustment valve
with Flow sensor
Gas proportional valve
Gas solenoid valve 1
Air-fuel ratio rod
Gas solenoid valve 3
Inlet
Thermistor Transformer
PCB