Paloma PH-28RIFSN User manual

R
Tankless Gas Water Heaters
PH-28RIFSN; PH-28CIFSN (Indoor) (NAT. Gas)
PH-28RIFSP; PH-28CIFSP (Indoor) (L.P. Gas)
PH-28ROFN; PH-28COFN (Outdoor) (NAT. Gas)
PH-28ROFP; PH-28COFP (Outdoor) (L.P. Gas)
PH-28RDVSN; PH-28CDVSN (Direct Vent) (NAT. Gas)
PH-28RDVSP; PH-28CDVSP (Direct Vent) (L.P. Gas)
(R: Residentail Model; C: Commercial Model)
Engineering Handbook
D
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®
CERTIFIED
R
Indoor Water Heater Outdoor Water Heater Direct Vent Water Heater

- Do not store or use gasoline or other flammable vapors and liquids in the
vicinity of this or any other appliance. To do so may result in an explosion or fire.
- WHAT TO DO IF YOU SMELL GAS
* Do not try to light any appliance.
* Do not touch any electrical switch; do not use any phone in your building.
* Immediately call your gas supplier from a neighbor's phone. Follow the gas
supplier's instructions.
* If you cannot reach your gas supplier, call the fire department.
* Do not return to your home until authorized by the gas supplier or fire department.
- Installation and service must be performed by a qualified installer, service
agency or the gas supplier.
WARNING: If the information in these instructions is not followed
exactly, a fire or explosion may result causing property damage,
personal injury or death.
WARNING: Improper installation, adjustment, alternation, service or maintenance
can cause property damage, personal injury, or death. For assistance or additional
information, consult with a qualified distributor.
WARNING: The content on this manual is intended for use by qualified service
personnel ONLY.
Table of Contents
- 2 -
Page
Specifications ................................................................. 3
External Dimensions ...................................................... 4 ~ 5
Schematic Construction ................................................. 6 ~ 8
Operational Principle ..................................................... 9 ~ 12
Capacity ......................................................................... 13 ~ 14
Wiring Diagram ............................................................. 15
Operational Flow Chart & Maintenance Information.... 16
Diagnostic Points ........................................................... 17 ~ 22
Hints for Diagnosis ........................................................ 23 ~ 34
Adjustment ..................................................................... 35 ~ 47
How to Disassemble Each Parts ..................................... 48 ~ 52
Schematic Disassembly and Parts List .......................... 53 ~ 67

SPECIFICATIONS (Approx.)
Model PH-28RIFSN (NAT)
PH-28RIFSP (L.P.)
PH-28CIFSN (NAT)
PH-28CIFSP (L.P.)
PH-28ROFN (NAT)
PH-28ROFP (L.P.)
PH-28COFN (NAT)
PH-28COFP (L.P.)
PH-28RDVSN (NAT)
PH-28RDVSP (L.P.)
PH-28CDVSN (NAT)
PH-28CDVSP (L.P.)
Purpose Domestic Hot Water Supply & Circulating
Rated Gas Input
(Btu/Hr.) 19,000 (Min.) 199,900 (Max.)(Modulating) 19,000 (Min.) 199,900 (Max.)(Modulating) 19,000 (Min.) 199,900 (Max.)(Modulating)
Dimensions (in.) 14 7/8 (W) x 25 3/8 (H) x 11 1/8 (D)
Net Weight (lbs.) 65
Installation Indoor Wall Mounting Type
Can be vented either hori-
zontally or vertically
Outdoor Wall Mounting
Type Direct Vent Indoor Wall Mounting Type
Can be vented either hori-
zontally or vertically
Working Water Pressure 14 psi ~ 150 psi
Minimum Water Flow 0.66 GPM
Maximum Flow Rate 7.4 GPM at 45ºF Temperature Rise
Gas Connection 3/4” NPT Female (w/supplied Gas Shutoff Valve)
Water Connection 3/4” NPT Male
Vent Size 4” Special Venting
(Category III) N/A (Outdoor Installation) 4” Special Venting (Category III)
Max. Vent Length 37.5 Feet Three 90º Elbow N/A(Outdoor Installation) 37.5 Feet Three 90º Elbow
Efficiency Rating 84%
Energy Factor 0.82
Inlet Gas Pressure
before water heater Natural Gas: Min. 4.0” w.c. Max. 10.5” w.c. L.P. Gas: Min. 8.0” w.c. Max. 14.0” w.c. (Do not exceed maximum pressure.)
Hot Water Supply Factory Setting 100ºF
Adjusting Range R:100ºF ~ 120ºF (140ºF); C: 100°F ~ 180°F
Max. Setting Up to 140ºF(R) or 180°F(C)(w/ Main Remote Control &
Dip Switch Adj.)
Electrical Portion Electrical Rating 120VAC/60Hz, Less than 2 Amps
Power Supply Cord 3 Pin Power Supply Cord 10 Feet (Indoor & Direct Vent)
Safety Devices Oxygen Depletion Safety Sensing Burner (Indoor & Direct Vent)
Over Heat Limiter Film Type for Entire Heat Exchanger
Flame Failure Safety Flame Rod Type
Freeze Protection Minus 30ºF (Without Wind-Chill Factor)
Optional Accessory First Bath Remote Control (USC1-117); Second Bath Remote Control (USC2-117)
DUOnex ™ for 2-Unit Manifolding
MIC-180 for Multi-Unit System Controller (2 to 6 units); MICS-180 for Expansion Board
(Up to 20 units); MIC Communication Cables (16, 32 & 65 feet)
High Altitude Adjustment Chips for use at altitudes above 3,280 feet, and up to 9.840 feet
Hot Water Flow Rate and Temperature Rise
Temp. Rise (ºF) 45 50 60 70 80 90 100
Water Flow (GPM) 7.4 6.7 5.6 4.8 4.2 3.7 3.4
- 3 -
Note: Special Venting: The adapter, vent pipe, elbow, vent terminal, etc. Should be UL 1738 Certified Category III Stainless
Steel Venting Material (e.g. AL29-4C). “B” vent is not permitted.
Since we are constantly improving our products, all specifications are subject to change without notice.

EXTERNAL DIMENSIONS
(PH-28RIFS & PH-28CIFS Indoor Model)
- 4 -
(PH-28ROF & PH-28COF Outdoor Model)
POWER SUPPLY CORD HOLE
COLD WATER INLET
6.34”(161mm)
6.34”(161mm)
8.39”(213mm)
4.69”(119mm)
14.96”(380mm)
5.12”(130mm)
3.45”(87mm)
HOT WATER OUTLET
1.93”(49mm)
5.51”
(140mm)
2.52”
(64mm)
4.17”(106mm)
GAS INLET
1.57”6.81”(173mm)
5.79”(147mm)
WIRING HOLE
25.39”(645mm)
27.36”(695mm)
1.89”(48mm)
1.97”(50mm)
Ø4”(101.6mm)
11.10”(282mm)
0.39”(10mm)
3/4"NPT(M)
3/4"NPT(M)
(W/Supplied Gas Shutoff Valve)
3/4"NPT(M)
(40mm)
0.59”(15mm)
0.59”(15mm)
8.17”(207mm)
8.82”(224mm)
2.13”(54mm)
0.73” (18.5mm)
25.39”645mm) 27.36”(695mm)
26.46”(672mm)
0.33” (8mm)
1.89” (48mm)
1.97” (50mm)
6.30”(160mm) 6.10”(155mm)
8.39”(213mm)
4.69”(119mm)
5.51”
(140mm)
2.52”
(64mm)
4.17”
(106mm)
5.79”(147mm)
6.81”173mm)
14.29”(363mm)
1.97” (50mm)
1.57” (40mm)
1.93”(49mm)
1.73”(44mm)
3.19” (81mm)
14.96”(380mm)
3.54”(90mm)
5.12”(130mm)
WIRING HOLE
POWER SUPPLY CORD HOLE
COLD WATER INLFT
HOT WATER OUTLET
GAS INLET
0.43”
(11mm)
9.02’ (229mm)
9.02”(229mm)
11.10”(282mm)
0.39”
(10mm)
3/4"NPT(M)
3/4"NPT(M)
(W/Supplied Gas Shutoff Valve)
3/4"NPT(M)

EXTERNAL DIMENSIONS
(PH-28RDVS & PH-28CDVS Direct Vent Model)
- 5 -
(Remote Control)
COMBUSTION
INDICATOR
POWER ON/OFF
INDICATOR
POWER ON/OFF
BUTTON
PRIORITY INDICATOR
TEMPERATURE
ADJUSTMENT
BUTTON
LED DISPLAY
POWER
ON/OFF
PRIORITY
°
F
7/8” (21mm)
4 3/4” (120mm)
4 3/4” (120mm)
1 7/8” 46mm)
3 1/4” (83.5mm)
6.34”(161mm)
POWER SUPPLY CORD HOLE
COLD WATER INLFT
6.34”(161mm)
8.39”(213mm)
4.69”(119mm)
5.51”
(140mm)
HOT WATER OUTLET
3.45
1.89”(48mm)
27.36”(695mm)
25.39”(645mm)
14.96”(380mm)
5.12”
(130mm)
5.12”(130mm)
2.52”
(64mm)
4.17”
(106mm)
GAS INLWR
1.576.81”(173mm)
5.79”(147mm)
1.93”(49mm)
WIRING HOLE
1.97”(50mm)
0.39”(10mm)
11.10”(282mm)
Ø4”(101.6mm)
3/4"NPT(M)
3/4"NPT(M)
(W/Supplied Gas Shutoff Valve)
3/4"NPT(M)

SCHEMATIC CONSTRUCTION
- 6 -
No. Name of Parts No. Name of Parts No. Name of Parts
1 Front Cover 11 Sensing Burner Assembly 21 Water Inlet Connection
2 Back Cover 12 Orifice Stand LAssembly 22 Hot Water Outlet Connection
3 Air Filter Assembly 13 Orifice Stand RAssembly 23 Drain Valve
4 Exhaust Flue Top 14 Electrode 24 Water Control Body Assy.
5 Heat Exchanger 15 Fan Assembly 25 PC Board
6 Heat Transfer Coil 16 Gas Control Valve Assembly 26 Film Type OHL
7 Water Supply Coil 17 Water Supply Pipe
8 Turbulence Plate 18 Hot Water Supply Pipe
9 Inner Case 19 Bypass Pipe
10 Main Burner 20 Gas Connection
(PH-28RIFS & PH-28CIFS Indoor Model)
1
4
2
19
12
17
18
26
6
8
5
7
10
14
11
13
9
15
3
16
20
21
23
22
24
25
Hot Water Outlet
Connection 3/4” NPT (M)
Water Inlet Connection
3/4” NPT (M)
Gas Connection 3/4” NPT (F)
(W/Supplied Gas Shutoff Valve)

- 7 -
SCHEMATIC CONSTRUCTION
(PH-28ROF & PH-28COF Outdoor Model)
No. Name of Parts No. Name of Parts No. Name of Parts
1 Front Cover 11 Orifice Stand LAssembly 21 Hot Water Outlet Connection
2 Back Cover 12 Orifice Stand R Assembly 22 Drain Valve
3 Rain Cover 13 Electrode 23 Water Control Body Assy.
4 Flue Outlet 14 Fan Assembly 24 PC Board
5 Heat Exchanger 15 Gas Control Valve Assembly 25 Film Type OHL
6 Heat Transfer Coil 16 Water Supply Pipe
7 Water Supply Coil 17 Hot Water Supply Pipe
8 Turbulence Plate 18 Bypass Pipe
9 Inner Case 19 Gas Connection
10 Main Burner 20 Water Inlet Connection
14
22
5
19
12
7
20
2
24
15
3
11
6
8
25
18
13
1
23
9
4
17
21
16
10
Hot Water Outlet
Connection 3/4” NPT (M)
Water Inlet Connection
3/4” NPT (M)
Gas Connection 3/4” NPT (F)
(W/Supplied Gas Shutoff Valve)

- 8 -
SCHEMATIC CONSTRUCTION
No. Name of Parts No. Name of Parts No. Name of Parts
1 Front Cover 11 Orifice Stand LAssembly 21 Hot Water Outlet Connection
2 Back Cover 12 Orifice Stand R Assembly 22 Drain Valve
3 Air Intake 13 Flame Rod 23 Water Control Body Assy.
4 Exhaust Flue Top 14 Fan Assembly 24 Film Type OHL
5 Heat Exchanger 15 Gas Control Valve Assembly 25 Sensing Burner Assembly
6 Heat Transfer Coil 16 Water Supply Pipe 26 Burner Rod
7 Water Supply Coil 17 Hot Water Supply Pipe
8 Turbulence Plate 18 Bypass Pipe
9 Inner Case 19 Gas Connection
10 Main Burner 20 Water Inlet Connection
(PH-28RDVS & PH-28CDVS Direct Vent Model)
6
2
5
1
8
7
4
3
9
10
11
12
14
15
16
17
18
19
20
21
22
23
24
25
26
13

- 9 -
OPERATIONAL PRINCIPLE
No. Name of Parts No. Name of Parts No. Name of Parts
1 Hot Water Tap 11 Solenoid Valve 2 21 Exhaust Outlet
2 Bypass Solenoid Valve 12 Solenoid Valve 3 22 Combustion Chamber
3 Water Flow Sensor 13 Proportional Gas Control Valve 23 Freeze Protection Heater
4 Water Inlet Thermistor 14 Orifice 24 Fan
5Heat Exchanger Thermistor 15 Main Burner 25 Fan Motor
6Hot Water Outlet Thermistor 16 Igniter 26 Drain Valve
7 Water Flow Servo 17 Electrode 27 PC Board
8 Water Filter 18 Flame Rod
9 Gas Inlet Solenoid Valve 19 Heat Exchanger
10 Solenoid Valve 1 20 Film Type OHL
M
M
Hot Water
Outlet
Gas
Inlet
21
19
14
15
16
18
22
20
23
27
25
24
5
17
7
2
4
3
8
1
26
6
13
9
12
10
11
Water
Inlet

- 10 -
OPERATIONAL PRINCIPLE
WHEN SUPPLYING HOT WATER
1) By opening the Hot Water Top (1), the water flows through the Water Flow Sensor (3) to the Heat
Heat Exchanger (19).
2) The frequency signal is given from the Water Flow Sensor (3) and when the PC Board (27) senses the signal
that reached a certain frequency, the Fan (24) starts to turn round.
3) After the Fan (24) turned round and pre-purged, the Gas Inlet Solenoid Valve (9), Solenoid Valve 1 (10) and
Solenoid Valve 2 (11) open at the same time. Then, the Proportional Gas Control Valve (13) becomes an
ignition motion and allows the gas to flow to the Main Burner (15) (and Sensing Burner for PH-28RIFS,
PH-28CIFS, PH-28RDVS and PH-28CDVS only).
4) At the same time, the Igniter (16) continuously makes sparks and ignites the Main Burner (15).
After ignited, when the Flame Rod (18) senses the flame and make sure the combustion, the Proportional
Gas Control Valve (13) finishes the ignition motion.
5) After finished the ignition motion, the proportional gas control is started. When there is a temperature
difference between the hot water temperature that is sensed by the Hot Water Outlet Thermistor (6) and the
set temperaturer on the Remote Control, the PC Board (27) judges it and open or close the Solenoid
Valve 1 (10), Solenoid Valve 2 (11) and Solenoid Valve 3 (12), and also the Proportional Gas Control Valve
(13) continuously adjusts the gas volume in order to maintain the outlet temperature from the Heat
Exchanger (19).
The Water Flow Servo (7) also adjusts the proper amount of water flow to supply a stable hot water
temperature at all times.
6) According to the adjustment of the gas volume by the Proportional Gas Control Valve (13), a signal from the
PC Board (27) is also sent to the Fan Motor (25) in order to maintain the relation between the gas volume
and air volume at all times.
7) (For PH-28RIFS, PH-28CIFS, PH-28RDVS and PH-28CDVS only) When the air intake or venting is
blocked, or the oxygen of the air intake is not sufficient, the output of the Thermocouple that is located at the
Sensing Burner would be changed. The PC Board (27) senses this change and controls the Fan (24),
Proportional Gas Control Valve (13), etc. in order to prevent the imperfect combustion. Further, if such
condition is proceeded, it shuts off the Gas Inlet Solenoid Valve (9), Solenoid Valve 1 (10),
Solenoid Valve 2 (11), Solenoid Valve 3 (12) and Proportional Gas Control Valve (13) in order to stop the
operation.
8) When the Hot Water Tap (1) is closed, the frequency signal from the Water Flow Sensor (3) is stopped and
the Gas Inlet Solenoid Valve (9), Solenoid Valve 1 (10), Solenois Valve 2 (11), Solenoid Valve 3 (12) and
Proportional Gas Control Valve (13) turn off and becomes a post-purge motion.
9) When the time of the post-purge is up, the Fan (24) stops.

- 11 -
[Sensing Burner]
The sensing burner is a all primary air type ceramic burner that consists of an outer jacket surrounding the flame
opening and a thermocouple to detect flame temperature. In case oxygen level decreases due to blocked or
clogged air intake or flue venting, or by contaminated air, location of the flame will change as well as its
temperature by the thermocouple. The sensing burner is located in the part of the main burner and designed to
monitor the flame condition at all times. Therefore, it shut off gas before the imperfect combustion occurs in the
main burner.
Oxygen Depletion Safety Device (O.D.S.D.)
NORMAL
========
BLOCKING LACK OF OXYGEN
The flame lifts away
from the thermocouple.
The flame lifts away
from the thermocouple.
(Blocked or clogged vent, fan etc.) (Contaminated air in room, etc.)
========================
ThermocoupleThermocouple Thermocouple
Primary Air
Primary Air Primary Air
(Lack of Oxygen)
Secondary Air
Gas Gas Gas
(Decrease)
(Indoor Model & Direct Model Only)

- 12 -
If Imperfect Combustion Happens.....
Ignition Normal Air
Flow Rate
Extinction
Post- Purging
Sensor Stand-By
Lead Time
Cold: 2 Min.
Hot: 30 Sec. - 1 Min.
Water Flow
Servo OFF
Decrease of Thermo
Electric Current
Input Down
(Increase Air
Flow Rate)
Automatic Control To Resolve
Imperfect Combustion
Decrease of Thermo
Electric Current
Primary Warning
(Light)
Decrease of Thermo
Electric Current
Decrease of Thermo
Electric Current
Secondary Warning
(Alarm + Light)
Shut Down
(After- Purging)
Monitor Code
No Error
Code
Both Red and Green
flashing at the same time
05
Both Red and Green
flashing at the same time
Every 60 seconds, you hear
noticing alarm (Beep sound).
Monitor Code
Monitor Code
6 times
13
Only Red lamp flashing
(Indoor Model &
Direct Model Only)
(Display on Remote Control)
NOTE: Shutdown by impeefect combustion can be reset by pressing power switch (ON/OFF Button).
However, if it occurs 5 times within 4 hours, the water heater will not recover for the next 4 hours.

- 13 -
Capacity
Hot Water Capacity Curve: Residential Models
0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0
100
110
120
130
140
Inlet Water Temperature : 40°F
Water Flow Rate (GPM)
Outlet Temperature (°F)
0.66
GPM
7.4
GPM
When maximum temperature is set at 140°F
When maximum temperature is set at 120°F
0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11 . 0
100
110
120
130
140
Inlet Water Temperature : 50°F
Water Flow Rate (GPM)
Outlet Temperature (°F)
When maximum temperature is set at 140°F
When maximum temperature is set at 120°F
0.66
GPM
7.4
GPM
0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0
100
110
120
130
140
Inlet Water Temperature : 60°F
Water Flow Rate (GPM)
Outlet Temperature (°F)
When maximum temperature is set at 140°F
When maximum temperature is set at 120°F
0.66
GPM
7.4
GPM
0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11 . 0
100
110
120
130
140
Inlet Water Temperature : 70°F
Water Flow Rate (GPM)
Outlet Temperature (°F)
When maximum temperature is set at 140°F
When maximum temperature is set at 120°F
0.66
GPM
7.4
GPM
Water Flow Rate (GPM)
Water Pressure (psi)
4.3
4.8
5.3
5.8
6.4
6.9
7.4
Inlet Water Temperature: 70
°F
Inlet Water Temperature: 40°F
(7.4)
(4.8)
14 30 45 60 105 120 135
(At The Outlet Hot Water Temperature : 110 )
°F
Water Pressure & Water Flow Rate:

- 14 -
Capacity
Hot Water Capacity Curve: Commercial Models
Water Flow Rate (GPM)
Water Pressure (psi)
4.3
4.8
5.3
5.8
6.4
6.9
7.4
Inlet Water Temperature: 70
°F
Inlet Water Temperature: 40°F
(7.4)
(4.8)
14 30 45 60 105 120 135
(At The Outlet Hot Water Temperature : 110 )
°F
Water Pressure & Water Flow Rate:
0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11 . 0
100
110
120
130
140
Inlet Water Temperature : 40°F
Water Flow Rate (GPM)
Outlet Temperature (°F)
0.66
GPM
7.4
GPM
150
160
170
180
When maximum temperature is set at 180°F
When maximum temperature is set at 120°F
0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11 . 0
100
110
120
130
140
Inlet Water Temperature : 50°F
Water Flow Rate (GPM)
Outlet Temperature (°F)
0.66
GPM
7.4
GPM
When maximum temperature is set at 180°F
When maximum temperature is set at 120°F
150
160
170
180
0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0
100
110
120
130
140
Inlet Water Temperature : 60°F
Water Flow Rate (GPM)
Outlet Temperature (°F)
150
160
170
180
0.66
GPM
7.4
GPM
When maximum temperature is set at 180°F
When maximum temperature is set at 120°F
0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11 .0
100
110
120
130
140
Inlet Water Temperature : 70°F
Water Flow Rate (GPM)
Outlet Temperature (°F)
150
160
170
180
0.66
GPM
7.4
GPM
When maximum temperature is set at 180°F
When maximum temperature is set at 120°F

- 15 -
Wiring Diagram
B
8
R GR Y B O
W
BR
AIR INTAKE FILTER SWITCH
TRANSFORMER
GND
BK
GND
WATER FLOW SENSOR
OVER HEAT LIMITER
BK:BLACK
COLOUR CODE
BR:BROWN
R:RED
W:WHITE
B:BLUE
GY:GRAY GR:GREEN
O:ORANGE
Y:YELLOW
G/Y:GREEN/YELLOW
REMOTE REMOTE REMOTE
(UMC-117)
(USC1-117)
(USC2-117)
FAN MOTOR
FM
5
WIRING DIAGRAM
FUSE(3A)
CIRCUIT
BOARD
SV3 SV2
SV1
SV0
W B R O Y
W
W
CONNECTOR FOR CHECKING THERMOELECTROMOTIVE FORCE
FUSE (5A)
2 1
U
2 1
O
S
1 3 2
B
R
GR
Y B O
W
R1
BR
R2
R3R4
GR GR GY GY
W Y R R
R
BR B Y
W
R
W
W
R
W
BK
BK BK
BK
BK
BK BK BK BK BK BK
BK BK
W
BK
IGNITER
ELECTRODE
W
1 2 3 4 5 6 7
1 2
1 2
8
1
2
3
4
Q
P
R
1 2 3 4 5 6
1 2 3 4 5 6 7
OFF
ON
1
2 3 4
I J
H
F
D E
B
A
PSV
M
L
- +
K
G
T
CONTROL MOTOR
WATER VOLUME
LIMITER
MOTOR
SW2
SW1
SW3
R
R
G/Y BK
W
AC 100V
G/Y
W
AC 120V
FOR INDOOR MODEL ONLY
1
4
5 6 3
2
3 6
5
2
1
4
IG
WV
B
DIP SWITCH
ADJUSTER
BUTTON
MIN
BUTTON MAX
BUTTON
MAIN
WATER BY-PASS SOLENOID VALVE
V A
L
V E
3
S
O
L
E
N
O
I
D
V A
L
V E
2
S
O
L
E
N
O
I
D
V A
L
V E
1
S
O
L
E
N
O
I
D
V A
L
V E
0
S
O
L
E
N
O
I
D
G
A S
I
N
L
E
T
T
H
E
R
M
I
S
T
O
R
A
I
R
A
M
B
I
E
N
T
T
H
E
R
M
I
S
T
O
R
I
N
L
E
T
W
A
T
E
R
T
H
E
R
M
I
S
T
O
R
E
X
C H
A
N
G
E
R
H
E A
T
T
H
E
R
M
I
S
T
O
R
H
O
T
W
A
T
E
R
O
U
T
L
E
T
V A
L
V E
FROST PROTECTION THERMOSTAT
WW
W
W W
BK BK
BK
BK
BK
WW
W
W
W
BK
FOR INDOOR MODEL ONLY
ANTI-FROST HEATER
T
H
E
R
M
O
C
O
U
P
L
E
(BLUE)
(RED)
(RED)
R
W
CONTROL
BATH BATH
CONTROL1
CONTROL2
LED
FLAME ROD1 FLAME ROD2 FLAME ROD3
THE CONNECTORS OF DUAL AND MULTIPLE
ARE INTERAPPLICABLE TO THE BODY CONNECTORS EACH OTHER.(RED)
A wiring diagram is also located on the inside of the front cover panel.
Slightly different by model and serial number.

Operational Flow Chart & Maintenance Information
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Diagnostic Points
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The voltage showed is the value of operating condition when the water heater operates according to the flow chart.
The resistance showed is the value of load side when turned off the electric power and disconnected the connector.
k5

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MAINTENANCE INFORMATION SHOWN IN LED DISPLAY OF REMOTE CONTROL
ABOVE
- 19 -

- 20 -
Error Codes
Code Fault Remedy
05 Imperfect Combustion Alarm Clean air inlet filter.
Clean combustion air fan.
Clean heat exchanger fins.
Check for adequate combustion air ventilation openings and clean if neces-
sary.
Check vent system for partial blockage and correct as necessary.
10 Decrease of Fan Motor Ventilation
Amount
Air Supply or Exhaust Blockage
(Warning)
Check all vent components for proper connections.
Check that nothing is blocking the flue inlet or exhaust.
Ensure condensation trap/drain was installed correctly.
Ensure heat exchanger fins, fan, and air intake are not blocked.
11 Ignition Failure
No Ignition Ensure you have gas to the appliance and valves are turned ON. Ensure gas type and pressure is correct.
Bleed all air from gas lines.
Ensure gas line, meter, and regulator are sized properly.
Ensure appliance is properly grounded.
Check gas solenoid valves for open or short circuits.
Ensure igniter is operational.
Check igniter wiring harness for damage.
Ensure maximum vertical vent length does not exceed allowable limits.
Ensure total maximum vent length does not exceed allowable limits.
12 Flame Failure Ensure you have gas to the appliance.
Ensure gas type and pressure is correct.
Bleed all air from gas lines.
Ensure flame rod wire is connected.
Check flame rod for carbon build-up.
Ensure gas line, meter, and regulator are sized properly.
Ensure appliance is properly grounded.
Check gas solenoid valves for open or short circuits.
Check power supply for proper voltage and voltage drops.
Disconnect remote control; if it runs.
Disconnect and re-connect all wiring harnesses on unit and PC board.
Ensure proper venting material was installed.
Ensure maximum vertical vent length does not exceed allowable limits.
Ensure total maximum vent length does not exceed allowable limits.
13 Oxygen Depletion Sensor (O.D.S.)
Working (Poor or Improper Com-
bustion)
Ensure there is plenty of fresh air to the unit.
Unit needs 1 square inch (6.5 cm2) for each 1,000 BTU of input.
Check for a foreign materials in combustion chamber and/or O.D.S. De-
vice.
14 Over Heating Ensure high fire and low fire manifold pressure is correct.
Check gas type of unit and ensure it matches gas type being used.
Check heat exchanger for cracks and/or separations.
Check for restrictions in airflow around unit and vent terminal.
Check for a foreign materials in combustion chamber and/or exhaust pip-
ing.
Check for clogged heat exchanger (scale buildup).