Bock Water heaters HEC Series User manual

Energy Saver
HEC Series
High Efficiency Water Heaters
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualied service providers)
For Models
60HEC-125
60HEC-150
60HEC-199
100HEC-150
100HEC-199
100HEC-250
100HEC-300
100-HEC399
All are available in LP or Natural Gas
Standard or ASME Construction
Manual 45817B - Save this manual for future reference

HEC Series
High Efficiency Water Heaters
Table of Contents
Page HEC Service Procedure
Introduction 3 - - -
How to use this manual 4 - - -
Tool required for service 4 - - -
Specications 5 ---
Sequence of Operation 8 - - -
Troubleshooting 12 - - -
Thermostat Circuit, Testing & Replacement 14 I
Combustion System Testing & Replacement 20 II
Burner Tube Inspection & Replacement 24 III
Gas Valve Replacement 26 IV
Blower Testing & Replacement 27 V
Exhaust Pressure Switch Testing & Replacement 29 VI
HotSurfaceIgnitorTesting&Replacement 35 VII
Flame Sensor Testing & Replacement 37 VIII
Ignition Module Replacement 39 IX
Transformer Replacement 40 X
Intake Pressure Testing & Replacement 41 XI
Vent Safety Switch Testing & Replacement 43 XII
Anode&FlueBafeInspection&Replacement 45 XIII
InstallationCheckList 50 ---
HeaterServiceReport 51 ---
GlossaryofTerms 52 ---
2

3
HEC Series
Introduction
TheBockHECSeriesHighEfciencyWaterHeaterisdesignedtodelivera
remarkablethermalefciencyratinginaquietrunningunitwithventingoptions
thatallowforinstallationexibility.Severaltechnologicallyadvanceddesign
features are incorporated in the design that will require additional knowledge
onthepartofthequaliedserviceprovider.Theinformationinthismanualwill
instruct service and a maintenance professionals on the function, roper diagnosis
andrepairoftheBockHECSeriesHighEfciencyWaterHeater.
TheBockHECSeriesHighEfciencyWaterHeaterusesalowNox
premix power burner located at the top of the water heater to direct a turbulent
amedownintoasubmergedcombustionchamber.Thisturbulencecausesa
thoroughmixingofgasandairforoptimumcombustion.Thecombustiongases
thentravelthroughathreepassuesystemkeepingthegasesmovingatahigh
velocity.Thecombinationofhighturbulenceandvelocityresultsinanoptimum
transferofheatfromtheuegasesintothewater.
Burneroperationiscontrolledusinganelectronicignitionmodule.Themodule
monitors the status of the electronic thermostat, vent temperature limit switch,
ventsystempressureswitchesandaamesensortocontroloutputvoltage
toblowermotor,hotsurfaceigniterandgasvalve.Themodulecontains
programming which determines the sequence of operation and timings for purge
periods,trialforignition,amesensingandlockout.Themodulewillalsoprovide
diagnostic information on LEDs to help in determining the cause of system
lockouts.
The contents of this manual are detailed informational tools to assist in the
properdiagnosisoftheHECSeriesHighEfciencyWaterHeateroperational
faults.Pleasethisservicemanualcompletelyandprovideasmuchinformation
regardingtheHECSeriesHighEfciencyWaterHeateroperationandinstallation
specicconcerns.

4
HEC Series How to Use this Manual
Itisintendedforthismanualtobeusedbyqualiedservicepersonnelfortheprimarypurpose
oftroubleshootinganalysisandrepairoftheBockHECSeriesHighEfciencyWaterHeater.
Understanding the sequence of operation section of this manual will contribute greatly to
troubleshootingthisproduct.
An“InstallationCheckList’isshownonpage50.Comparetheinstallationagainsttheinstallation
checklisttoconrmallrequirementsaremet.
An“HECServiceReport”isshownonpage51.Completingthisformwillassistinthe
troubleshootingefforts.Showyouneedtocallfortechnicalsupport,pleaseprovidethe
informationshownonthisformtothesupporttechniciantoinsureaccuratetroubleshooting.
Troubleshooting begins with “System Observation” to determine failure mode as indicated by the
LEDstatusoftheignitionmodule.Troubleshootingcontinueswith“FailureModesandProbable
cause” listed on page 11, directing the service provider to a series of test procedures to determine
rootcauseoffailure.Componentreplacementproceduresdirectlyfollowthetestproceduresfora
givencomponent.
Insomedifculttodiagnoseconditions,itmaybenecessarytoisolatetheheaterfromthevent
systemtodeterminetherootcause.
Contact Technical Support immediately if diagnosis is not determined using the methods described
inthisservicemanual.
Tools Required for Service
Manometer: Twotypesavailable,aliquid“U”tubetypeoradigital(magna-helic)type.
Thisdeviceisusedtomeasuregasand/orairpressuresandvacuum.
Multi-Meter: Adigitaltypeisstronglyrecommended.Thisdeviceisusedtomeasure
electricalvalues.Themeteryouselectmusthavethecapabilityto
measurevoltsAC,voltsDC,Amps,micro-ampsandohms.
Thermometer: Usedtomeasurewatertemperature.Anaccuratethermometeris
recommended.
WaterPressureGage: Usedtomeasurewatersupplypressure.Alsousedtodeterminetank
pressurebyadaptingtothedrainvalveoftheheater.
JumperLeads: Alengthofwire(12”min.)withalligatorclipsatbothends.
Various Hand Tools: Pipe wrench, channel locks, open end wrench set, 12” crescent wrench,
allen wrench set, torx bit set, screw drivers (common & phillips), long
reach (12”) magnetic tip phillips head screw driver #2 tip, ¼” nut driver,
pliers (common & needle nose), socket set including 1-1/16” deep well
socket, wire cutters, wire strippers, wire crimpers, torpedo level, small
shopvac,stepladder,andashlight.

5
HEC Series Specications
NOTE: Diagrams are for both the 60 and 100 gallon models
¾” NPT Gas Inlet
1" NPT Space
Heating Outlet
1" NPT Space
Heating Return
1 ½"NPT Inlet
3" PVC Exhaust
3” PVC Air Inlet
G E
B
D
3" PVC
Exhaust
½” NPT
Condensate
Connection
F
ACH
T & P Valve
Cleanout
Drain
B - 28 ¼
Gas Inlet
Exhaust
Air Intake
2 ⁄”
8 ¼
8 ¼
T & P Valve
1 ½” NPT
Outlet
MODEL
NUMBER
DIMENSIONS IN INCHES
A
HT. B DIA.
C
HOT
OUT
D
COLD
IN
E
GAS
CONN.
F
FL. TO
VENT
OUTLET
G
FL. TO
AIR
INTAKE
H
FL. TO
T&P
VALVE
WATER
CONN.
DIA.
60 Gallon Models 57 28 1/4 42 13 531/2 5 521/2 40 1 1/2
100 Gallon Models 775/8 28 1/4 63 13 74 3/4 5 74.75 60 1.5
MODEL
NUMBER STORAGE (GAL)
RATED
INPUT
(BTUH) THERMAL EFF %
1ST HR
DEL GAL.
@ 100° F
RISE
RECOVERY GPH @
DEGREE RISE
MAX 3”
PVC,
ABS &
CPVC
MAX 4”
PVC,
ABS &
CPVC SHIPPING WT (LBS)
40° F 100° F 140° F
60HEC-125 60 125,000 96.0% 187 364 145 104 120 ft 170 ft 570
60HEC-150 60 150,000 93.0% 211 423 169 121 100 ft 150ft 570
60HEC-199 60 199,999 92.0% 265 558 223 159 80 ft 130 ft 900
100HEC-150 100 150,000 99.1% 250 450 180 129 120 ft 170 ft 900
100HEC-199 100 199,999 98.5% 309 597 239 171 100 ft 150ft 900
100HEC-250 100 250,000 97.0% 364 735 294 210 80 ft 130 ft 900
100HEC-300 100 300,000 92.0% 405 836 335 239 60 ft 110 ft 900
100-HEC-399 100 399,999 93.0% 521 1127 451 322 50ft 100 ft 950

6
HEC Series Specications
Power Supply Dedicated120VAC,60Hz,15A,GFI
Gas Supply Minimum1”NPTforHEC100-399,allothers3/4”NPT
(schedule 40 black iron pipe recommended)
Approved Gas Type NaturalorPropane.Unitmustmatchgastypesupplied
GasPressure(Nat.&
L.P.)
14.0”W.C.maximumstatic,4.5”W.C.minimumrunning(recommend7.0”W.C.min
running)
Venting System Powervent,balanceddirectventorunbalanceddirectvent.Seeventtablesonpage7
Approved Vent
Materials PVC, CPVC or ABS
Minimum Clearance for
Servicing 18” from top, 24” from front, 4” sides and rear
MaximumWater
Supply Pressure 150PSI
Thermostat Sensor 11,900 Ohms @ 70°F, ECO opens @ 201°F Maximum, ECO close @ 100°F Minimum
Temperature Dial Minimumsetpoint5400-6600Ohms,Maximumsetpoint0-50Ohms
Thermostat Board Maximum temperature 180°F, minimum temperature 91°F, 24VAC, 60Hz Maximum
Ignition Module See page 11
Transformer 120VAC primary, 24VAC secondary, 40VA
Hot Surface Igniter 120VAC, 30-120 Ohms @ room temperature
Flame Sensor Output Minimum 1 micro amp, typical range 4 to 7 micro amps
Gas Valve Negativeregulation,24VAC,½“PSImaximum,4.5”W.C.Minimumrunninginlet
Vent Safety Switch Normallyclosed,opens@350°F, manual reset
Intake Pressure Switch
“CF” serial number or
later NotRequired
Intake Pressure Switch
serial numbers prior to
“CF” 24VAC,normallyclosed,opensonvacuumincrease@-1.20W.C.
Blocked Vent Pressure
Switch “CF” serial
number or later 24VAC,normallyclosed,openswhenpressureincreasesto+2.70W.C.
Exhaust Pressure
Switch serial numbers
prior to “CF”
24VAC, normally open, closes on pressure increases as follows:
Note1: +2.58”W.C.-60HEC-150,100HEC-199
+1.50”W.C.-100HEC-150(seenote2)
+1.22”W.C.-60HEC-150,100HEC-250
+2.08”W.C.-60HEC-125
+0.55”W.C.-100HEC-300(seenote3)
Note2:+5.6”W.C.onserialspriortoAH5039107
Note3:+0.8”W.C.onserialspriortoAK5288269
Blower 120VAC,60Hz,.6-1amps,6400RPM
Combustion Levels CO2:10-11%;CO:lessthan0.04percent(400PPM)airfree

7
HEC Series Specications
Vent Tables
Balanced Direct Vent Systems
PVC, CPVC or ABS
Total length of intake piping and exhaust
piping added together must not exceed
“Maximum Combined Length”
shown below
Maximum Combined Length (feet)
Model Number 3” 4”
60HEC-125, 100HEC-150 120’ 170’
60HEC-150, 100HEC-199 100’ 150’
60HEC-199, 100HEC-250 80’ 130’
100HEC-300 60’ 110’
100HEC-399 50’ 100’
Unbalanced Direct Vent Systems
Air intake CANNOT exceed exhaust
by more than 30 feet
Power Vented Systems
PVC, CPVC OR ABS
Total length of exhaust piping must not
exceed “Maximum Vent Length”
shown below
Maximum Vent Length (feet)
Model Number 3” 4”
60HEC-125, 100HEC-150 120’ 170’
60HEC-150, 100HEC-199 100’ 150’
60HEC-199, 100HEC-250 80’ 130’
100HEC-300 60’ 110’
100HEC-399 50’ 100’
Notes:
1) Multiply the total number of 90°elbows(intakeandexhaust)by5feet.Donotincludethe
terminationttingsor3”condensateelbow.
2) Multiplythetotalnumberof45°elbows (intake and exhaust) by 2½feet.
3) Addthistothetotallengthofstraightpipe-intakeandexhaust.
4) The sum total of all elbows and straight pipe - intake and exhaust must not exceed maximum
lengthsfromtablesabove.
Example: 100HEC-199
A 3” Balanced Direct Vent System has 30 feet of straight exhaust pipe and 30 feet of straight
intakepipe.Ithasthree90°elbows in the exhaust and three 90°elbowsintheintake.Ithasone
45°elbowintheexhaustandone45°elbowintheintake.
Therefore:
6 - 90°elbowsx5feet=30feet
2-45°elbows x 2½feet=5feet
60feetofstraightpipe+30feet+5feet=95feet
System is within “Maximum Combined Length” from table above

8
HEC Series Sequence of Operation
For models prior to CF serial numbers
1. Thermostatcallsforheat.
- Prior to energizing blower, ignition module checks safety circuits for normal switch positions:
a) Vent temp switch normally closed
b) Intake pressure switch normally closed
c) Exhaust pressure switch normally open
If the vent temp switch is open, the control waits indenitelyfortempswitchtoclose(greenlightstayson).
 Iftheexhaustpressureswitchcontactsareclosed(notinnormalposition),theignitionmodulewillwait45
secondsforpressureswitchcontacttoopenbeforeenergizingblower.Ifafter45secondsandpressure
switchcontactsdonotopen,theignitionmodulelocksoutwiththePURGElightashingindicatingpressure
switchfault.
2. Blowerenergizes
3. Pressureswitchprovesblower/ventsystemoperation
 IftheN.O.Contactsoftheexhaustpressureswitchdonotclosewithin5minutesoftheblowerbeingon,the
controllocksoutwiththePURGElightashingindicatingpressureswitchfault.
4. Blowerpre-purgeperiod(5seconds)indicatedbythePURGELEDonthemodule.
5. Igniterwarmup(18seconds),indicatedbytheIGNITERLEDonthemodule.
6. Trialforignition(4seconds,threetrials).
a) Flameestablishingperiod(2.5seconds)gasvalveandigniteron,indicatedbytheIGNITERand
VALVE LED on the module
b) Burneron,ameprovidingperiod(1.5seconds,lookingforminimumof1microamps),indicatedby
theFLAME&VALVELEDonthemodule.
7. Steadystateoperation.Ignitionmodulemonitors.
 -Thermostatcircuit.
  -Whenthermostatopens,gasvalveisshutdownandpostpurgebegins.
 -Safetycircuit.
- If vent temp switch opens, gas valve is shut down, system will post purge and wait for switch to close
beforeattemptingre-ignition.
- Ifeitherpressureswitchopens,gasvalveisshutdown.Blowerisshutdownfor30secondsafter
which blower is re-energized and system attempts re-ignition starting at pressure switch proving
mode.
-Flamesensorcircuit.
- Ifameislost,gasvalveisshutdown,systemwillpostpurgeandsystemattemptsre-ignitionstarting
atpressureswitchprovingmode.
8. Thermostatsatised.
9. Burneroff.
10. Blowerpostpurge(15seconds).

9
HEC Series Sequence of Operation
For models prior to CF serial numbers
Lockout Conditions
 Ifnormallyclosedpressureswitchcontactsopenduringburneroperation,gasvalvecloses,burnershutsoff.
Blowerrestartsafter30secondsandruns5minutestowaitforpressureswitchtoclose.Ifnot,locksout.
The system will go into lock out mode for the following reasons:
- Pressure switches stuck open or closed
a) Checkforexhaustorintakeobstructions.
b) Checkforcompliancewithventtables.
c) Check for evidence of moisture or condensate present in pressure switch tubing or pressure
switch.
-Noignitionafter3attempts.
a) Checkgaspressures.
b) Igniterresistancetoohigh(lowerresistancepreferred<150Ohms).
c) Check venturi screw adjustment (6 ½turnsfrombottom).
d) Flamesensemicroampnotpresent(1to5microampsrequired).
Lock out reset is accomplished by shutting OFF the line voltage to the system or opening the 24V thermostat
circuitforatleast2seconds.
 Systemwillautomaticallyresetlockoutafter1hourofcontinuouscallforheatfromthethermostat.Three
ignitiontrialswillbeattemptedeachhouruntilthethermostatissatised.
IgnitionModuleSpecications
Control Function:
- Ignition & heating functions in response to thermostat
-Hotsurfaceignitionusingamicroprocessortocontroltiming,amesensingusingamerectication&
ignitionretries.
- Monitoring of system pressure switches and limit switches
- Control of gas valve, inducer motor, and hot surface igniter element based on thermostat demand and
statusofsafetyinputs.
- Diagnosticindicatorstoprovideinformationonpowertocontrolandcontrolstatus.
- Non-interchangeablepolarizedplug-inconnectorsforallinterconnections
Control Inputs: Control Outputs:
- Thermostat call for heat - Inducer motor
- Limit switch circuit (normally closed) - Hot surface igniter
- Pressure switch circuit (normally open) - Gas valve
- Flame sensing - Status indicator LEDs
- Low voltage supply Power - Green
- Line voltage supply Purge - Red
Igniter - Red
Valve - Red
Flame - Red
IGNITION MODULE
UT ELECTRONIC
CONTROLS
P2
P3
P5
P1
P7 P6
HUNTINGTON, INDIANA
1013 SERIES INTEGRATED WATER HEATER
POWER
PURGE
IGNITOR
VALVE
FLAME
INDICATOR
LIGHTS
FOR OPERATING SEQUENCE TROUBLESHOOTING SEE INSTALLATION
AND OPERATING INSTRUCTION MANUAL
ANSI Z21.20 AUTOMATICIGNITION SYSTEMS
CAN/CSA-22.2 NO. 199-M89
24 VAC 0.5AMP 50/60Hz
IF SYSTEM LOCK OUT, REMOVE POWER FOR 45 SECONDSTO RESET
SYSTEM WILL AUTOMATICALLY RE-TRYAFTER 1 HOUR
WARNING
EXPLOSION HAZARD, CAN CAUSE
SERIOUS INJURY OR DEATH
THIS DEVICE CAN MALFUCTION IF IT GETS
WET. NEVER TRY TO USE A DEVICE THAT
HAS BEEN WET - - REPLACE IT.
POWER
PURGE
IGNITOR
VALVE
FLAME
FS
BLOWER
PRIMARY HSI
120V AC IN
RED/SOCKET
WHITE/PIN
RED/PIN
CONTROL
RED/SOCKET
P6
P7
P1
P5
AN1
AN2
AN3
AN4
AN5
SECONDARY
WHITE/PIN
WHITE/PIN
P2
P3
Y
TRANSFORMER
115V AC INPUT
24V AC OUTPUT
BL BL
YBK
GN
W
1
P2 2 P2 1 P1 2 P1 3 P1
W
GN/Y
BK
TOGGLE SWITCH
Y
Y
BK
115 VOLTS AC
N
GND
LT
POTENTIOMETER
UPPER
SENSOR
POT.
R-C COM
N.O.
SEN-1 S-1
LOWER S-1
24V T-24
T-24H
R
R-N.O.
ELECTRONIC
THERMOSTAT
BL
BL
R
R
R R
R
BL
BR
GN
GY
GY
P.S. N.C. P.S. N.O.
N.C. TEMP SWITCH
G
TOGGLE SWITCH
LIGHT
MV
GAS VALVE
ELECTRONIC
CONTROL
MODULE
W
W
GN
BK
W
BK
IGNITOR
BLOWER
MOTOR
FLAME SENSOR
FS
3 P7
2 P7
1 P7
7 P3
9 P3
2 P3
3 P3
1 P3
4 P3
6 P3
5 P3
8 P3
P6 1
P6 2
P5 1
P5 2
P5 3
P5 4
WIRING DIAGRAM

10
HEC Series Sequence of Operation
For models starting with
CF serial numbers and later
1. Thermostatcallsforheat.
Prior to energizing blower, ignition module checks to make sure the vent temperature switch is in the nor-
mallyclosedposition.Iftheventtemperatureswitchisopen,thecontrolwaitsindenitelyforthetemperature
switchtoclose.
2. Blowerenergizes,pressureswitchcontactsarenormallyclosed.Ifthepressureswitchcontactsareopen,
bloweroperatesforupto5minuteswaitingforcontactstoclose,thenblowerstopsandashesredPURGE
LEDindicatinglockoutcondition.
3. Blowerpre-purgeperiod(5seconds)indicatedbythePURGELEDonthemodule.
4. Igniterwarmup(18seconds),indicatedbytheIGNITERLEDonthemodule.Note:theblockedventpres-
sureswitchmustbeinthenormallyclosedpositionfortheignitioncycletostart.
5. Trialforignition(4seconds,threetrials).
a) Flameestablishingperiod(2.5seconds)gasvalveandigniteron,indicatedbytheIGNITERand
VALVE LED on the module
b) Burneron,ameprovidingperiod(1.5seconds,lookingforminimumof1microamps),indicatedby
theFLAME&VALVELEDonthemodule.
6. Steadystateoperation.Ignitionmodulemonitors.
 -Thermostatcircuit.
  -Whenthermostatopens,gasvalveisshutdownandpostpurgebegins.
 -Safetycircuit.
- If vent temp switch opens, gas valve is shut down, system will post purge and wait for switch to close
beforeattemptingre-ignition.
- If the blocked vent pressure switch opens, indicating a blocked exhaust vent condition, the gas valve
is shut down, blower shuts down for 30 seconds and is re-energized and system attempts re-ignition
ifthepressureswitchisclosed.Bloweroperatesfor5minutestowaitforpressureswitchtoclose,
thenshutsoffwithpurgelightashing(lockout).Willrestartin1hourtoattempttoclosetheswitch
andrestartignitionsequence.
- Flamesensorcircuit.
- Ifameislost,gasvalveisshutdown,systemwillpostpurgeandsystemattemptsre-ignition.
7. Thermostatsatised.
8. Burneroff.
9. Blowerpostpurge(15seconds).

HEC Series
Lockout Conditions
The system will go into lock out mode for the following reasons:
Blocked vent pressure switch contacts open
- Check for obstruction in exhaust pipe and vent terminal
 - Checkforblockedcondensatetrapordrainline.Incoldclimates,makesuredrainisnotfrozen.
 Noignitionafter3attempts
 - Checkinletandoutletgaspressures(pressuretapslocatedontopofgasvalve).
 - Igniterresistancetoohigh(lowerresistancepreferred<150Ohms).
- Misadjusted venturi screw (should be 6 ½turnsoutfrombottom).
 - Flamesensemicroampsshouldnotpresent(1to5microampsrequired).Ifburnerlit,checkamerod
 fordeposits.
 - Checkburnertubeconditions.RefertosectionServiceProcedureIIIforburnertubeinspectionand
replacement.
IgnitionModuleSpecications
Control Function:
- Ignition & heating functions in response to thermostat
-Hotsurfaceignitionusingamicroprocessortocontroltiming,amesensingusingamerectication&
ignitionretries.
- Monitoring of system pressure switches and limit switches
- Control of gas valve, inducer motor, and hot surface igniter element based on thermostat demand and
statusofsafetyinputs.
- Diagnosticindicatorstoprovideinformationonpowertocontrolandcontrolstatus.
- Non-interchangeablepolarizedplug-inconnectorsforallinterconnections
Control Inputs: Control Outputs:
- Thermostat call for heat - Inducer motor
- Blocked vent pressure switch (normally closed) - Hot surface igniter
- Flame sensing - Gas valve
- Low voltage supply - Status indicator LEDs
- Line voltage supply Power - Green
Purge - Red
Igniter - Red
Valve - Red
Flame - Red
Sequence of Operation
For models starting with
CF serial numbers and later
11
IGNITION MODULE
UT ELECTRONIC
CONTROLS
P2
P3
P5
P1
P7 P6
HUNTINGTON, INDIANA
1013 SERIES INTEGRATED WATER HEATER
POWER
PURGE
IGNITOR
VALVE
FLAME
INDICATOR
LIGHTS
FOR OPERATING SEQUENCE TROUBLESHOOTING SEE INSTALLATION
AND OPERATING INSTRUCTION MANUAL
ANSI Z21.20 AUTOMATICIGNITION SYSTEMS
CAN/CSA-22.2 NO. 199-M89
24 VAC 0.5AMP 50/60Hz
IF SYSTEM LOCK OUT, REMOVE POWER FOR 45 SECONDSTO RESET
SYSTEM WILL AUTOMATICALLY RE-TRYAFTER 1 HOUR
WARNING
EXPLOSION HAZARD, CAN CAUSE
SERIOUS INJURY OR DEATH
THIS DEVICE CAN MALFUCTION IF IT GETS
WET. NEVER TRY TO USE A DEVICE THAT
HAS BEEN WET - - REPLACE IT.
POWER
PURGE
IGNITOR
VALVE
FLAME
FS
BLOWER
PRIMARY HSI
120V AC IN
RED/SOCKET
WHITE/PIN
RED/PIN
CONTROL
RED/SOCKET
P6
P7
P1
P5
AN1
AN2
AN3
AN4
AN5
SECONDARY
WHITE/PIN
WHITE/PIN
P2
P3
1
P2 2
P2 1
P1 2
P1 3 P1
ELECTRONIC
CONTROL
MODULE
FS
3 P7
2 P7
1 P7
7 P3
9 P3
2 P3
3 P3
1 P3
4 P3
6 P3
5 P3
8 P3
P6 1
P6 2
P5 1
P5 2
P5 3
P5 4
W
W
GN
BK
W
BK
IGNITOR
BLOWER
MOTOR
FLAME SENSOR
TRANSFORMER
115V AC INPUT
24V AC OUTPUT
BL
YBK GN W
W
GN/Y
BK
TOGGLE SWITCH
Y
Y
G
TOGGLE SWITCH
LIGHT
GY
GY
N.C. TEMP SWITCH
R
R
BL
BR
GN
P.S. N.C.
MV
GAS VALVE
POTENTIOMETER
UPPER
SENSOR
POT.
R-C COM
N.O.
SEN-1 S-1
LOWER S-1
24V T-24
T-24H
R
R-N.O.
ELECTRONIC
THERMOSTAT
BL
BL
R
R
BK
115 VOLTS AC
N
GND
LT
GN/Y
W
BK
POWERED ANODE ON
399,999 BTUH MODELS ONLY
L
N2 1
WIRING DIAGRAM

12
HEC Series Troubleshooting
System Observation
Refer to ignition module
illustration, is there 120VAC
between P1(1) and P1(3)?
Is front panel power
switch light on,
indicating power?
Y
NPosition front panel
power switch to
“ON” position.
Is there 120VAC
across switch?
(see photo at right)
Light burned out,
replace switch.
Y
Is there 120VAC
across terminal block?
(see photo at right)
N
Determine power
source problem and
correct.
Repair/replace wire
harness to switch.
Y
N
Is ignition module
power light on? N
Y
Refer to ignition module
illustration, is there 120VAC
going to module at locations
P7(1) and P7(3)?
N
Replace ignition module. Replace transformer.
NN
YY
Is ignition module
power and flame light
flashing?
Reset heater by
interrupting power.
Reestablish power and
Adjust thermostat to
call for heat,
tank must be cold.
Allow heater to run
through heating cycle.
Did heater complete
heating cycle and did
blower post purge? See next page
System is OK.
Supply voltage polarity
is incorrect.
Y
N
N
Y
Refer to ignition module
illustration, is there 24VAC
going to module at locations
P2(1) and P2(2)?
WARNING
120 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
Power Switch
Terminal Block
Replace ignition module.
(see pg 39) (see pg 39) (see pg 40)
IGNITION MODULE
UT ELECTRONIC
CONTROLS
P2
P3
P5
P1
P7 P6
HUNTINGTON, INDIANA
1013 SERIES INTEGRATED WATER HEATER
POWER
PURGE
IGNITOR
VALVE
FLAME
INDICATOR
LIGHTS
FOR OPERATING SEQUENCE TROUBLESHOOTING SEE INSTALLATION
AND OPERATING INSTRUCTION MANUAL
ANSI Z21.20 AUTOMATIC IGNITION SYSTEMS
CAN/CSA-22.2 NO. 199-M89
24 VAC 0.5 AMP50/60Hz
IF SYSTEM LOCK OUT, REMOVE POWER FOR 45 SECONDS TO RESET
SYSTEM WILL AUTOMATICALLY RE-TRY AFTER 1 HOUR
WARNING
EXPLOSION HAZARD, CAN CAUSE
SERIOUS INJURY OR DEATH
THIS DEVICE CAN MALFUCTION IF IT GETS
WET. NEVER TRY TO USE A DEVICE THAT
HAS BEEN WET - - REPLACE IT.
POWER
PURGE
IGNITOR
VALVE
FLAME
FS
BLOWER
PRIMARY HSI
120V AC IN
RED/SOCKET
WHITE/PIN
RED/PIN
CONTROL
RED/SOCKET
P6
P7
P1
P5
AN1
AN2
AN3
AN4
AN5
SECONDARY
WHITE/PIN
WHITE/PIN
P2
P3

HEC Series
13
Troubleshooting
System Observation
Determine failure mode by observing flashing LED status on ignition module.
LED status and probable cause shown below.
* Denotesconditions thatmay require the water heater to be isolated from the vent
system to determine root cause.
LED STATUS
Power & flame
light flashing.
Probable Cause
Supply voltage
polarity.
LED STATUS
Valve light flashing.
Probable Cause
Flame sensor.
(see “Flame Sensor
Testing and Replacement”)
Probable Cause
Hot surface igniter.
(see “Hot Surface
Igniter Testing and
Replacement”)
Probable Cause*
Combustion system.
(see “Combustion
System Testing and
Replacement”)
Probable Cause*
Intake pressure switch. Only for
models prior to CF serial number
(see “Intake Pressure Switch
Testing and Replacement”)
Probable Cause
Blower.
(see “Blower Testing
and Replacement”)
Probable Cause*
Exhaust pressure
switch. (see “Exhaust
Pressure Switch
Testing and
Replacement”)
LED STATUS
Purge light flashing.
LED STATUS
Only power light
is on and water heater
will not function.
Probable Cause
Thermostat circuit.
(see pg 14)
Probable Cause*
Exhaust pressure
switch. (see “Exhaust
Pressure Switch
Testing and
Replacement”)
Probable Cause
Vent safety switch.
(see pg 43)

14
HEC Series Service Procedure I
Thermostat Circuit Testing & Replacement
Refer to ignition module
illustration, Is there 24VAC
between P3(7) and P3(8)?
Y
OK, thermostat is
calling for heat.
Turn off power to heater.
Disconnect YELLOW and RED wires from the
thermostat board at location N.O. and COM shown in
photo at right. Use a jumper to connect these two
wires together as shown in photo at right.
Restore power to heater.
Did heater cycle on?
N
Check thermostat sensor
for proper resistance
(OHMS) across blue wires.
(See Appendix A, sensor
resistance)
Are readings correct?
(see photo at right)
Check temperature dial for
proper resistance (OHMS)
(See Appendix B,
temperature dial resistance)
Are readings correct?
(see photo at right)
Y
Y
Replace
thermostat sensor.
(see Thermostat Sensor
Replacement Procedure)
Replace temperature dial
(potentiometer).
(see Thermostat Potentiometer
Replacement Procedure)
N
N
N
Replace thermostat
circuit board.
(see Thermostat Board
Replacement Procedure)
Y
Check sensor harness
continuity.
Is there continuity?
Check temperature dial
harness continuity.
Is there continuity?
Replace harness.
Y
N
Replace harness.
N
Y
See page 16
IMPORTANT NOTE: This procedure assumes a cool tank
Rotate temperature
dial to highest setting.
Thermostat
not calling
WARNING
120 volt potential exposure. Use
caution making voltage checks
to avoid personal injury.
Thermostat
Sensor
Temperature Dial
Yellow & Red
wires shown
jumpered
Yellow Wire
(COM)
Red Wire
(N.O.)
IGNITION MODULE
UT ELECTRONIC
CONTROLS
P2
P3
P5
P1
P7 P6
HUNTINGTON, INDIANA
1013 SERIES INTEGRATED WATER HEATER
POWER
PURGE
IGNITOR
VALVE
FLAME
INDICATOR
LIGHTS
FOR OPERATING SEQUENCE TROUBLESHOOTING SEE INSTALLATION
AND OPERATING INSTRUCTION MANUAL
ANSI Z21.20 AUTOMATICIGNITION SYSTEMS
CAN/CSA-22.2 NO. 199-M89
24 VAC 0.5AMP 50/60Hz
IF SYSTEM LOCK OUT, REMOVE POWER FOR 45 SECONDSTO RESET
SYSTEM WILL AUTOMATICALLY RE-TRYAFTER 1 HOUR
WARNING
EXPLOSION HAZARD, CAN CAUSE
SERIOUS INJURY OR DEATH
THIS DEVICE CAN MALFUCTION IF IT GETS
WET. NEVER TRY TO USE A DEVICE THAT
HAS BEEN WET - - REPLACE IT.
POWER
PURGE
IGNITOR
VALVE
FLAME
FS
BLOWER
PRIMARY HSI
120V AC IN
RED/SOCKET
WHITE/PIN
RED/PIN
CONTROL
RED/SOCKET
P6
P7
P1
P5
AN1
AN2
AN3
AN4
AN5
SECONDARY
WHITE/PIN
WHITE/PIN
P2
P3

HEC Series
15
Service Procedure I
Thermostat Circuit Testing & Replacement
°F 012345678 9
40 2610925400 24712 2404523399 2277122163 2157321000 20445
50 1990619383 18876 1838317905 1744016990 1655316128 15715
60 1531414925 14548 1418013823 1347713140 1281212494 12185
70 1188411592 11308 1103210763 1050210248 10000 9760 9526
80 9299 9078 8862 8653 8449 8250 8057 7869 76857507
90 7333 7165 7000 6839 6683 6531 6383 6238 60985961
100 5827 5697 5570 5446 5326 5208 5094 4982 4873 4767
110 4663 4562 4464 4368 4274 4183 4094 4006 3922 3839
120 3758 3679 3602 3527 3453 3382 3312 3244 3177 3112
130 3048 2986 2925 2866 2808 2752 2697 2643 2590 2538
140 2488 2439 2391 2344 2298 2253 2209 2166 2124 2083
150 2043 2004 1966 1928 1891 1856 1820 1786 1753 1720
160 1688 1656 1625 1595 1566 1537 1509 1481 1454 1427
170 1402 1376 1351 1327 1303 1280 1257 1235 1213 1191
180 1170 1150 1129 1110 1090 1071 1053 1035 1017 999
190 982 965 949 933 917 901 886 871 857 842
200 828 814 801 788 775 762 749 737 725 713
In Degrees F
APPENDIX - A
Sensor Resistance at Various Temperatures
Example: If temperature of sensor is 84°F,then the resistance through the sensor would be 8449 (see shaded area).
NOTE: Sensor resistance increases as the temperature falls.
Be Careful When Making Voltage Measurements or Jumping Terminals
Not to Damage or Deform Connectors or Connector Pins.
APPENDIX - B
Temperature Dial Resistance
Proper Readings Should Be 5400-6600 Ohms at Minimum
Setting
And 0-50 Ohms at Maximum.
Be Careful When Making Voltage Measurements or Jumping Terminals
Not to Damage or Deform Connectors or Connector Pins.
Draw Water From The T&P Valve. Compare Temperature With
Temperature Ohms Chart Below.

16
HEC Series Service Procedure I
Thermostat Circuit Testing & Replacement
Refer to ignition module
illustration, Is there 120VAC
between P1(1) and P1(3)?
Refer to ignition module
illustration, Is there
22 - 27VAC between
P2(1) and P2(2)?
Refer to ignition module
illustration, Is there 120VAC
between P7(3) and P7(1)?
Replace transformer.
(see Transformer
Replacement)
Refer to ignition module
illustration, Is there 24VAC
between P3(9) and P2(1).
N
N
Y
Y
Check wire harness
continuity. Replace
thermostat sensor or wire
harness as necessary.
(see “Thermostat Sensor
Replacement Procedure”)
Check AC source to
determine why there is no
power.
Replace
ignition module.
(see “Ignition Module
Replacement”)
N
Check continuity through
ECO, red wires of
thermostat sensor.
Check at temperature
less than 160°F
Is there continuity?
(see photo at right)
N
Replace ignition module.
(see “Ignition Module
Replacement”)
Y
Replace thermostat
circuit board.
(see “Thermostat Board
Replacement Procedure”)
Y
N
Y
Thermostat circuit.
(continued from page 14)WARNING
120 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
Red Wires
(Temperature Sensor)
IGNITION MODULE
UT
ELECTRONIC
CONTROLS
P2
P3
P5
P1
P7 P6
HUNTINGTON, INDIANA
1013 SERIES INTEGRATED WATER HEATER
POWER
PURGE
IGNITOR
VALVE
FLAME
INDICATOR
LIGHTS
FOR OPERATING SEQUENCE TROUBLESHOOTING SEE INSTALLATION
AND OPERATING INSTRUCTION MANUAL
ANSI Z21.20 AUTOMATIC IGNITION SYSTEMS
CAN/CSA-22.2 NO. 199-M89
24 VAC 0.5AMP 50/60Hz
IF SYSTEM LOCK OUT, REMOVE POWER FOR 45 SECONDSTO RESET
SYSTEM WILL AUTOMATICALLY RE-TRYAFTER 1 HOUR
WARNING
EXPLOSION HAZARD, CAN CAUSE
SERIOUS INJURY OR DEATH
THIS DEVICE CAN MALFUCTION IF IT GETS
WET. NEVER TRY TO USE A DEVICE THAT
HAS BEEN WET - - REPLACE IT.
POWER
PURGE
IGNITOR
VALVE
FLAME
FS
BLOWER
PRIMARY HSI
120V AC IN
RED/SOCKET
WHITE/PIN
RED/PIN
CONTROL
RED/SOCKET
P6
P7
P1
P5
1NA
2NA
3NA
4NA
5N
A
YRADNOCES
WHITE/PIN
WHITE/PIN
P2
P3

HEC Series
17
Service Procedure I
Thermostat Circuit Testing & Replacement
WIRING DIAGRAM
For models prior to
CF serial number
Step 5. Carefully disconnect all wires from thermostat
board.
Note: it may be necessary to identify wires
for proper re-connection.
Step 6. Remove the two screws (Phillips head screw
driver) that secure thermostat board to
control panel.
Step 7. Install new thermostat board to control panel using
screws from step 6.
Step 8. Carefully reconnect wiring per the wire
diagram below. Reconfirm wire
connections are correct prior to putting
heater back in service
Step 9. Restore 120 volt power supply to water
heater and confirm proper operation following
the lighting instructions on the lighting
instruction label or the lighting instruction
located in the installation and operating
instruction manual.
Step 10. Replace surround cover on top of heater.
Thermostat Board Replacement Procedure
Step 1. Position main power switch to “OFF”
Step 2. Disconnect (unplug) water heater from 120
volt power source.
Step 3. Un-latch and remove top surround cover
from top of heater.
Step 4. Locate thermostat board on control panel.
(see photo at right)
WIRING DIAGRAM
For models starting with
CF serial numbers and
later.
WARNING
120 volt potential exposure. Isolate the
appliance and reconfirm poweris
disconnected using a multi-meter.
Thermostat
Board
Mounting
screw locations
Y
TRANSFORMER
115V AC INPUT
24V AC OUTPUT
BL BL
YBK
GN
W
1
P2 2 P2 1 P1 2 P1 3 P1
W
GN/Y
BK
TOGGLE SWITCH
Y
Y
BK
115 VOLTS AC
N
GND
LT
POTENTIOMETER
UPPER
SENSOR
POT.
R-C COM
N.O.
SEN-1 S-1
LOWER S-1
24V T-24
T-24H
R
R-N.O.
ELECTRONIC
THERMOSTAT
BL
BL
R
R
R R
R
BL
BR
GN
GY
GY
P.S. N.C. P.S. N.O.
N.C. TEMP SWITCH
G
TOGGLE SWITCH
LIGHT
MV
GAS VALVE
ELECTRONIC
CONTROL
MODULE
W
W
GN
BK
W
BK
IGNITOR
BLOWER
MOTOR
FLAME SENSOR
FS
3 P7
2 P7
1 P7
7 P3
9 P3
2 P3
3 P3
1 P3
4 P3
6 P3
5 P3
8 P3
P6 1
P6 2
P5 1
P5 2
P5 3
P5 4
1
P2 2
P2 1
P1 2
P1 3 P1
ELECTRONIC
CONTROL
MODULE
FS
3 P7
2 P7
1 P7
7 P3
9 P3
2 P3
3 P3
1 P3
4 P3
6 P3
5 P3
8 P3
P6 1
P6 2
P5 1
P5 2
P5 3
P5 4
W
W
GN
BK
W
BK
IGNITOR
BLOWER
MOTOR
FLAME SENSOR
TRANSFORMER
115V AC INPUT
24V AC OUTPUT
BL
YBK GN W
W
GN/Y
BK
TOGGLE SWITCH
Y
Y
G
TOGGLE SWITCH
LIGHT
GY
GY
N.C. TEMP SWITCH
R
R
BL
BR
GN
P.S. N.C.
MV
GAS VALVE
POTENTIOMETER
UPPER
SENSOR
POT.
R-C COM
N.O.
SEN-1 S-1
LOWER S-1
24V T-24
T-24H
R
R-N.O.
ELECTRONIC
THERMOSTAT
BL
BL
R
R
BK
115 VOLTS AC
N
GND
LT
GN/Y
W
BK
POWERED ANODE ON
399,999 BTUH MODELS ONLY
L
N2 1

18
HEC Series Service Procedure I
Thermostat Circuit Testing & Replacement
Thermostat Potentiometer Replacement Procedure
Step 4. Loosen set screw of adjusting
knob (small blade screw driver)
and remove adjusting knob
from potentiometer. (see photos at right)
Step 5. Remove retaining nut (½" wrench)
and washer from potentiometer.
(see photos at right)
Step 6. From inside of surround area, remove potentiometer
with gasket from side of surround. Notice how indexing
tab on potentiometer assembles into locating hole of
surround. (see photos below)
Step 7. Disconnect potentiometer wire leads.
(see photo at right)
Step 8. Install new potentiometer with gasket into side of surround. Be sure to assemble with
indexing tab inserted into locating hole on side of surround (see photos above).
Step 9. Reconnect wires to potentiometer. Note: Wire leads are interchangeable with either wire.
Step 10. Restore 120 volt power supply to water heater and confirm proper operation following
the lighting instructions on the lighting instruction label or the lighting instruction located
in the installation and operating instruction manual.
Step 11. Replace surround cover on top of heater.
Step 1. Position main power switch to “OFF”
Step 2. Disconnect (unplug) water heater from
120 volt power source.
Step 3. Un-latch and remove top surround cover
from top of heater.
WARNING
120 volt potential exposure. Isolate the
appliance and reconfirm poweris
disconnected using a multi-meter.
Temperature
Adjusting Knob
Indexing
Tab
Locating
Hole
Loosen set screw
with small blade
screw driver
Remove
retaining nut
Potentiometer
Wire Leads

HEC Series
19
Service Procedure I
Thermostat Circuit Testing & Replacement
Thermostat Sensor (Thermister) Replacement Procedure
Step 5. Fold back insulation just in front of burner to expose temperature sensor (see photo below).
Step 6. Disconnect temperature sensor from harness (see photos below).
Step 7. Remove temperature sensor (1-1/16" hex, deep well socket) from heater.
Note: Using a deep well socket will allow room inside socket
for sensor connector and wires.
Step 8. Apply Teflon tape or applicable thread lubricant to threads of new sensor.
Install new thermostat sensor and Connect to wire harness from step 6.
Step 9. Fold insulation back into place. Be sure there are no wires in contact with burner.
Step 10. Restore 120 volt power supply and water supply to water heater, check and repair any
leaks found. Confirm proper operation following the lighting instructions on the lighting
instruction label or the lighting instruction located in the installation and operating
instruction manual.
Step 11. Replace surround cover on top of heater.
Step 1. Position main power switch to “OFF”
Step 2. Disconnect (unplug) water heater from
120 volt power source.
Step 3. Drain water down to the point below
the top of the tank.
Step 4. Un-latch and remove top surround cover from top of heater.
WARNING
120 volt potential exposure. Isolate the
appliance and reconfirm power is
disconnected using a multi-meter.
Disconnect sensor
from harness
Insulation folded
back to expose
temperature sensor

20
HEC Series Service Procedure II
Combustion System Testing & Replacement
Does inlet gas pressure
drop more than 2" W.C.
during burner ignition?
Adjust gas
supply regulator
Inadequately
sized regulator.
Y
N
N
Y
N
Y
N
Verify Minimum Gas Supply Piping Requirements of:
Minimum 1" NPT for EF100T399, all others use ¾"
NPT. (Schedule 40 black Iron Pipe recommended).
Reconfigure gas
supply piping
Y
Observe burner operation through the sight glass located on the combustion insert mounting flange.
Normal burner operation should ignite smoothly, without evidence of coughing or huffing upon
ignition. The burner flame should be a blue flame near the burner surface in a uniform flame pattern.
Occasional yellow or white streaks are normal.
Inlet gas
pressure tap
Venturi
adjustment
Is igniter resistance
less than 150 Ohms
(cold)?
(see check igniter
illustration)
Refer to ignition module illustration below,
is there 120VAC across terminals
P6(1) and P6(2)?
(Note: Igniter LED must be lit during this check).
Y
NReplace
hot surface igniter.
(see “Hot Surface Igniter
Replacement Procedure)
Replace ignition module.
(see “Ignition Module
Replacement Procedure”)
N
Y
Do you see the igniter
glowing through burner
site glass during the
warm up period?
Proceed to next page
With manometer, check inlet
gas pressure. Is it stable
between 7" & 14" W.C. static?
(heater not running)
(see illustrations at right)
Is gas supply pressure
regulator adjustable to
maintain proper and
stable setting?
Y
N
Volt meter set to
OHM setting
Meter probe
Hot surface
igniter
CHECK IGNITER
RESISTANCE
WARNING
120 volt potential
exposure. Use caution
making voltage checks to
avoid personal injury.
WARNING
Removing screw from
inlet gas pressure tap will
immediately allow gas to
flow from pressure tap.
Note: On higher input models using metal fiber mesh burner (serial
number “CK” and later) a red glow from the burner surface is normal.
IGNITION MODULE
UT
ELECTRONIC
CONTROLS
P2
P3
P5
P1
P7 P6
HUNTINGTON, INDIANA
1013 SERIES INTEGRATEDWATER HEATER
POWER
PURGE
IGNITOR
VALVE
FLAME
INDICATOR
LIGHTS
FOR OPERATING SEQUENCETROUBLESHOOTING SEE INSTALLATION
AND OPERATINGINSTRUCTION MANUAL
ANSI Z21.20 AUTOMATICIGNITION SYSTEMS
CAN/CSA-22.2 NO. 199-M89
24 VAC 0.5AMP 50/60Hz
IF SYSTEM LOCK OUT,REMOVE POWER FOR 45 SECONDS TO RESET
SYSTEM WILLAUTOMATICALLY RE-TRYAFTER 1 HOUR
WARNING
EXPLOSION HAZARD, CAN CAUSE
SERIOUS INJURY OR DEATH
THIS DEVICE CAN MALFUCTION IF IT GETS
WET. NEVERTRY TO USE A DEVICE THAT
HAS BEEN WET - - REPLACE IT.
POWER
PURGE
IGNITOR
VALVE
FLAME
FS
BLOWER
PRIMARY HSI
120V AC IN
RED/SOCKET
WHITE/PIN
RED/PIN
CONTROL
RED/SOCKET
P6
P7
P1
P5
1
N
A
2NA
3
N
A
4NA
5N
A
YRADNOCES
WHITE/PIN
WHITE/PIN
P2
P3
SIGHT GLASS