Dunkirk 95M-200 User manual

95M-200
GAS-FIRED DIRECT VENT
MODULATING HOT WATER BOILER
Control Manual And
Troubleshooting Guide
P/N# 240006104, Rev. F [09/2013]

2
1- Table Of Contents ...................................................................................................... 2
2 - Important Safety Information .................................................................................... 3
3 - Operating Information............................................................................................... 4
4 - Modulating Control Features....................................................................................... 6
5 - Boiler Startup .......................................................................................................... 7
6 - Checkout Procedures And Adjustments........................................................................ 9
7 - Detailed Sequence Of Operation ............................................................................... 12
8 - Service Hints ......................................................................................................... 13
9 - Troubleshooting...................................................................................................... 14
10 - User Interface Quick Reference............................................................................... 21
11 - Installation And Checkout Certicate ....................................................................... 28
1- TABLE OF CONTENTS

3
2 - IMPORTANT SAFETY INFORMATION
NOTICE
Used to address practices not related to personal
injury.
CAUTION
Indicates a hazardous situation which, if not avoided,
could result in minor or moderate injury.
!
WARNING
Indicates a hazardous situation which, if not avoided,
could result in death or serious injury.
!
DANGER
Indicates a hazardous situation which, if not avoided,
WILL result in death or serious injury
!
This is the safety alert symbol. Symbol alerts you to
potential personal injury hazards. Obey all safety messages
following this symbol to avoid possible injury or death.
Become familiar with symbols identifying
potential hazards.
General
Boiler installation shall be completed by qualied agency.
WARNING
Fire, explosion, asphyxiation and electrical shock
hazard. Improper installation could result in death or
serious injury. Read this manual and understand all
requirements before beginning installation.
!
Keep this manual near boiler
Retain for future reference
Installation shall conform to requirements of
authority having jurisdiction or in absence of such
requirements:
• United States
• National Fuel Gas Code, ANSI Z223.1/NFPA 54 .
• National Electrical Code, NFPA 70.
• Canada
• Natural Gas and Propane Installation Code, CAN/CSA
B149.1. and .2
• Canadian Electrical Code, Part I, Safety Standard for
Electrical Installations, CSA C22.1
Where required by authority having jurisdiction,
installation shall conform to Standard for Controls
and Safety Devices for Automatically Fired Boilers,
ANSI/ASME CSD-1.
Additional manual reset low water cutoff and/or manual
reset high limit may be required.
WARNING
Revision, modication, substitution or elimination of
factory equipped, supplied or specied components
could result in death or serious injury.
!
Use of this manual shall be by a qualied heating installer or
service technician only.
Before programming control read and understand all instructions
including :
• Installation, Operation and Maintenance Manual,
• Parameter Guide
• Control Manual and Troubleshooting Guide
Perform all steps in order specied.

4
3. DHW heating: Target temperature is determined by
adding Parameter 1 to Parameter 33 (default 150°F
and 30°F). Do not change Parameter 1 from factory
default setting of 150°F unless application is specially
engineered for other temperature. DHW heating default
setting is 180°F.
4. High limit operation: If outlet water temperature
exceeds target temperature (or 180°F, whichever is
lower), high limit action occurs. Control module shuts
burner off showing “b 9” followed by “26” on display.
5. DHW operation (if used): Boiler is factory set to
change target outlet water temperature to 180°F on
call for heat from DHW aquastat.
6. Additional Thermal Overrun Protection: High
limit operation shuts down burner when outlet
water temperature exceeds target temperature.
Adverse conditions could cause water temperature
to rise too quickly and overshoot this temperature.
Control’s advanced technology provides protection in
event of thermal overrun. Using its electronics, control
provides two additional levels of overrun protection:
•Level1: Indication occurs if supply water temperature
reached 183°F. Control displays soft lockout code (“b
9” followed by “18” if on supply or “19” if on return).
Control will not operate burner again until water
temperature dropped 9°F below target temperature.
•Level2: Lockout occurs if supply water temperature
reaches 200°F or if return water reaches 193°F. Control
will enter hard lockout and display error code (“E”
followed by “18” if on supply or “19” if on return).
NOTICE
Hard lockout requires manually pressing display panel
reset button to restart operation. Service technician
must troubleshoot cause of problem and correct it
before placing boiler back in operation.
Low Water/Low Flow Protection
1. Boiler is factory equipped with manual reset probe type
low water cutoff.
2. Boiler control uses temperatures sensed at both supply
and return areas of heat exchanger. If ow rate is
too low (temperature difference too high) or either
temperature is too high, control shuts boiler down.
Ensures boiler shutdown in event of low water or low
ow conditions.
Freeze Protection
Do not install boiler in room likely to freeze.
Following boiler control feature provides some protection for boiler
only, not for the system.
Boiler is controlled by microprocessor electronic control that
senses:
• Outlet water temperature,
• Return water temperature,
• Outdoor temperature (when factory supplied, eld
installed outdoor sensor is installed).
Information sensed plus input from external limit and
operating controls is used to regulate boiler on/off
operation and will modulate boiler ring rate to more
closely match output to demand.
Electrical Specications
Boilers require 120 VAC/60 HZ power supply and are not
polarity sensitive.
CONTROL SPECIFICATIONS
Supply voltage 120 Vac/60 hz
Electrical demand 10 VA
Pre-purge timing 10 Seconds
Post-purge timing 15 Seconds
Min. off time, space heating 10.2 Seconds
Pump on after space htg. 0 Minutes
Min. off time, DHW 10.2 Seconds
Pump on after DHW 30.6 Seconds
Line voltage fuse, F1 5 Amp fast-blow
Low voltage fuse, F3 4 Amp slow-blow
Boiler Circulator
• Circulator has sufcient head to handle boiler pressure
drop plus reasonable pressure drop in connecting
piping. See the Installation, Operation and Maintenance
Manual for piping information.
• Boiler control’s internal relay contact is suitable for
handling only the boiler circulator provided.
• Do not wire additional pumps in parallel with boiler
circulator.
• To operate system circulator when boiler circulator is
running, see “Electrical Wiring” section in Installation,
Operation and Maintenance Manual for wiring required.
Boiler Temperature Regulation
Operating temperature (target): Control senses outlet water
temperature and regulates boiler ring rate to achieve
target temperature set by installer using Parameter 4 .
Temperature can be set between 120°F and 194°F.
1. Space heating: Target temperature is xed (equal
to Parameter 4) when outdoor reset is not installed
or calculated as described under “Outdoor Reset
Operation” page 5, when outdoor sensor is connected.
2. Exception: See explanation of “Supply Temperature
Boost” page 5.
3 - OPERATING INFORMATION

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Control module provides freeze-up protection when boiler
water temperature drops below 45° F:
• Below 45° F, boiler circulator operates constantly.
• Below 37° F, boiler operates at low re.
• Boiler and circulator turn off if boiler water temperature
rises above 50° F.
This boiler control feature does not eliminate possibility
of freezing. Installation must use recognized design,
installation and maintenance practice to prevent freeze
potential for boiler and system.
Supply Temperature Boost
• Outdoor reset operation (factory supplied, eld installed
outdoor sensor connected), boiler control automatically
increases target outlet water temperature if call for
heat exceeds 10 minutes.
• At each 10 minutes of continuous call for heat, control
module increases target temperature by 18°F. Module
continues increasing target temperature until it reaches
value set in Parameter 4.
• When call for heat ends while target temperature is
“boosted,” target temperature drops about 2°F for each
minute thermostat is open.
Purpose of “Boosting” : If target temperature is too
low, control “boosts” target temperature until supply water
meets system needs.
Outdoor Reset Operation
Targettemperaturewithoutdoorreset: All boilers ship with
outdoor temperature sensor. When sensor is installed (low
voltage terminal strip terminals A1 and A2), boiler control
regulates target outlet water temperature based on outside
temperature.
Set temperature curve by setting Parameter 4 to:
• ODT (outdoor design temperature for the area).
• ODT of 0°F or lower, set Parameter 4 to desired supply
temperature at ODT.
• ODT above 0°F, set Parameter 4 to desired system
temperature when outdoor temperature is 0°F.
Resetcurve: See reset curve graph, shows how boiler
control calculates target temperature.
• Outdoor temperature at or below 0°F, target
temperature equals Parameter 4 and never higher.
• Outdoor temperature above 0°F, target temperature
is reduced on a curve that would result in 60°F supply
temperature at 70°F outdoor temperature.
Summer/winterswitchoption: Install summer/winter
switch, if desired, to disable boiler (space heating)
circulator during non-heating months. Connect switch
across outdoor sensor terminals. When switch closes, boiler
circulator is disabled and boiler operates only on call for
DHW heating.
DHW Operation (option)
Control allows connection of DHW aquastat to low voltage
terminal strip terminals DHW T1 and DHW T2. When
DHW aquastat calls for heat, module shuts down boiler
circulator activated DHW circulator and immediately sets
target outlet water temperature to 180°F. This provides
automatic priority heat allocation to indirect water heater
for maximum response and recovery. DHW circulator
continues for 30.6 seconds after heating cycle to deliver
heat.
3 - OPERATING INFORMATION
Target Outlet Temperature, °F
Outside Temperature, °F
Outdoor Reset Target Temperature
210
50
70 60 50 40 30 20 10 0 -10 -20
70
90
110
130
150
170
160
190
120
Parameter 4 = 190°F
Parameter 4 = 150°F
Parameter 4 = 170°F
Reset Curve Calculations
Reset Curve Calculations
Target Outlet Temperature, °F
Outside Temperature, °F
Default Reset Curve
Outdoor Reset Target Temperature
210
50
70 60 50 40 30 20 10 0 -10 -20
70
90
110
130
150
170
160
190
180
120
Parameter 7 = 60°F
Parameter 4 = 180°F
Parameter 6 = 0°F
Default Reset Curve

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Boiler Control Design
• Integrated modulating boiler control is designed for
central heating (CH) hot water boilers with modulating
fan and gas-air control.
• Modulation is based upon data relayed to control by
temperature sensors.
• Burner uses direct spark igniter (DSI).
• Modulating boiler control is intended for use in
combination with user interface display unit for both
information and operation.
• Control is designed for installation with conventional on/
off dry contact room thermostat.
• Control is able to provide hot water and outdoor reset
functions.
Main Controller Functions
Central Heat (CH): Control uses sensors on supply water,
return water and outside air to determine heat load of
heating system. Results in boiler supplying just enough
heat to satisfy demand which results in fewer overshoots
and less short cycling than conventional boiler.
Domestic Hot Water (DHW): When used in conjunction
with indirect hot water heater boiler has capability to
provide domestic hot water. An on/off dry contact aquastat
is used to activate call for domestic hot water.
Outdoor Reset: Control senses outside air temperature
using factory supplied, eld installed sensor. Controller
detects presence of sensor and reacts according to
parameters programmed into controller.
User Interface Display
User interface display allows installer and home owner to
scroll through control settings and customize boiler to heat
delivery system used in installation location. See “User
Interface Quick Reference” Section 10, page 21 for more
information on using and programming boiler control.
4 - MODULATING CONTROL FEATURES
IMPORTANT:
This boiler is equipped with a feature that saves energy
by reducing the boiler water temperature as the heating
load decreases. This feature is equipped with an override
which is provided primarily to permit the use of an external
energy management system that serves the same function.
This Override Must Not Be Used Unless At Least One Of The
Following Conditions Is True:
• An external energy management system is installed
that reduces the boiler water temperature as the
heating load decreases.
• This boiler is not used for any space heating.
• This boiler is part of a modular or multiple boiler
system having a total input of 300,000 BTU/hr or
greater.

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Startup
1. Start boiler after completing all instructions in
Installation, Operation and Maintenance Manual.
2. Start boiler by turning thermostat up to call for heat.
3. Once boiler has started and is operating, continue
startup procedure by performing all following steps to
set and verify operation of controls.
Set Space Heating Operation
1. Verify Space Heating Mode
A. Press “Mode” button until display shows [PARA].
This is parameter mode.
B. Press “Step” button until rst digit of display shows
“3.”
C. Last digit must show “1.” If any other number
displays, press “+” button until “1” shows in right-
hand digit, then press “Store” button to save this
setting.
2. Set space heating target temperature
A. Press “Step” button until rst digit of display
shows “4.” Last three digits show outlet water
temperature setting.
B. Press “+” or “-” buttons to change setting to
desired outlet water temperature. Factory default
setting is 180°F.
• Outdoor sensor installed: Setting is target
temperature for outdoor temperature at or
below factory setting (32°F). At higher outside
temperatures, control module calculates target
temperature.
• When summer/winter switch is used, closing
switch will disable boiler (space heating) circulator
during summer operation.
• Outdoor sensor not installed: Setting is target
temperature at all times.
C. Press “Store” button to save setting.
Check DHW Operation Setup
If control is already in parameter mode , skip step 1 (below)
and proceed to step 2.
1. Press “Mode” button until display shows [PARA]
(parameter mode).
2. Press “Step” button until rst digit of display shows “2.”
3. Last digit must show “1.” If another number displays,
press “+” button until “1” shows in right-hand digit,
press “Store” button to save this setting.
4. Control module turns on DHW circulator when indirect
water heater operating control closes. Control module
shuts off boiler circulator (stops space heating) during
calls for DHW heating.
Verify Operation – Space Heating
Information below presented in brackets “[ ]” represents
actual boiler control panel display with rst digit indicating
boiler status and last three digits showing measured boiler
water temperature. (Ex.- [A180] indicates status of “A” and
boiler water temperature of 180°F.)
1. Turn down DHW aquastat on DHW tank (if used). If
necessary, turn off power and remove one of DHW
aquastat wires to ensure boiler will not receive DHW
heat call.
2. Turn off power to boiler at service switch.
3. Wait few seconds, then turn on power to boiler.
• [180] Self-check on power-up for a few seconds.
• [0180] No call for heat.
4. Raise room thermostat to call for heat.
• [5180] Blower/boiler circulator on. Blower and boiler
circulator energize and control checks for air ow.
• [1180] Pre-purge. Blower speed will increase to ignition
speed. Blower will run in pre-purge for 10 seconds.
• [2180] Ignition. After pre-purge, control module opens
gas valve and starts ignition spark.
• If burner ame proves within 4.5 seconds, burner
continues to re. Burner will re at startup rate for
about 10 seconds to allow ame to stabilize.
• If burner ame does not prove within 4.5 seconds,
control module attempts ignition sequence again.
Flame must prove within 6 attempts or control will
lockout (display will show [E 02]).
• Verify ame failure operation by closing boiler manual
gas cock to prevent gas ow. Open manual gas valve
after testing.
• [3180] Burner on, space heating. Once ame is
proven and stable, burner turns down to low re for
approximately 2 minutes.
• After this low re period, burner is allowed to modulate.
Firing rate depends on actual outlet water temperature
versus target temperature.
5. Allow boiler to bring water temperature to target
temperature.
• [6180] Target temperature reached. Burner shuts
down. Blower runs in post-purge (see below), then
turns off. Boiler circulator continues to run as long as
there is call for heat.
6. Lower room thermostat to stop call for heat.
NOTICE
Instructions in this manual are based on factory
default parameter settings.
5 - BOILER STARTUP

8
• [1180] Post-purge. When room thermostat is satised
(call for heat ended), burner turns off. Blower continues
for 15-second post-purge, then turns off. If another
call for heat occurs, boiler remains off for ten seconds
before starting again, and display shows [6180].
• [0180] No call for heat. Boiler is in standby mode
(waiting for heat call).
7. Repeat steps 1-6 several times to verify operation.
8. Return room thermostat to normal setting.
Verify Operation – DHW
1. If necessary, reconnect DHW aquastat wiring to boiler.
2. Turn off power to boiler at service switch.
3. Wait few seconds, turn on power to boiler.
[A150] Self-check on power-up for a few seconds.
[0150] No call for heat.
4. Raise DHW aquastat above tank temperature to call for
heat.
• [5150] Blower/DHW circulator on. Blower and DHW
circulator energize and control checks for air ow.
• [1150] Pre-purge. Blower speed increases to ignition
speed. Blower runs in pre-purge for 10 seconds.
• [2150] Ignition. After pre-purge, control module opens
gas valve and starts ignition spark.
• If burner ame proves within 4.5 seconds, burner
continues to re. Burner res at startup rate for about
10 seconds to allow ame to stabilize.
• If burner ame does not prove within 4.5 seconds,
control module attempts ignition sequence again.
Flame must prove within 5 attempts or control will
lockout (display will show [E 02]).
• Verify ame failure operation by closing boiler manual
gas valve to prevent gas ow. Open gas valve after
testing.
• [4150] Burner on, DHW. Once ame is proven and
stable, burner is allowed to modulate. Firing rate
depends on actual outlet water temperature versus
target temperature.
5. Allow boiler to bring water temperature to target
temperature.
• [6150] Target temperature reached. Burner shuts
down. Blower runs in post-purge, then turns off. DHW
circulator continues to run as long as there is call for
DHW heating.
6. Lower DHW aquastat to stop call for heat.
• [1150] Post-purge. When room thermostat is satised
(call for heat ended), burner turns off. Blower continues
for 15 second post-purge, then turns off. If another
DHW heat call occurs, boiler begins heating cycle after
10 second delay. If CH call for heat occurs after DHW
demand, heating cycle begins after 30 second delay.
• [8150] DHW circulator run-on. DHW circulator
continues to run for 30 seconds.
• [0150] No call for heat. Boiler is now in standby mode
(waiting for heat call).
7. Repeat steps 1-6 several times to verify operation.
8. Return DHW aquastat to normal setting.
Operating Information
1. To check operating conditions (Ex - actual or target
temperature), see “User Interface Quick Reference”
Section 10 page 21, for explanation of boiler control’s
“Information” mode.
2. During normal operation (no shutdown or lockout),
right 3 display digits show actual boiler outlet water
temperature.
Perform Check-out Procedures
Complete “Checkout Procedures and Adjustments” as
indicated in Section 6 page 9.
Replace boiler front jacket panel after performing any service
to boiler.
5 - BOILER STARTUP

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Figure 1 - Gas Valve
Verify Sequence Of Operation
Detailed sequence of operation containing faults can be
found in Sections 7, “Detailed Sequence of Operation.”
Refer to this section and Section 8, “Service Hints,” for
more information.
Inspect Venting And Air Intake
Operate boiler and verify all vent/air intake connections are
gas tight and watertight. Repair any leaks immediately.
Inspect Condensate Drain And System Piping
Verify condensate ows freely and all connections are
watertight. Repair any leaks immediately.
Test Ignition System Safety Shutoff Device
1. Remove front panel from appliance.
2. Turn off manual gas ball valve.
3. Set thermostat for a call for heat.
4. Boiler begins normal sequence of operation.
5. After approximately 30 seconds of pre-purge appliance
will attempt to light.
6. After 4 seconds gas valve closes and control retries 5
times, before entering lockout mode.
7. To reset the control, follow the instructions in Section
IV of this manual, “Putting The Boiler In Operation.”
8. Return thermostat to previous setting.
Test And Adjust High Limit Control
• With burner operating, adjust setting on high limit
control below actual boiler water temperature.
• Burner will go off while circulator continues to operate.
• Raise limit setting above boiler water temperature and
burner will reignite after pre purge and igniter warm-up
period.
• Set high limit control to 10°F above parameter 4
setting as described in “Parameter Guide”.
• Maximum high limit setting is 200°F. Minimum high
limit setting is 100°F.
Test Low Water Cut Off
1. Disconnect wire from LWCO sensor probe.
2. Set thermostat for call for heat.
3. Boiler will not begin normal sequence of operation.
4. Attach wire to sensor probe.
5. Return thermostat to previous setting.
Test Other Field Installed Safety Controls (if
used)
If boiler is equipped with any additional safety controls, test
for operation as outlined by control manufacturer. Burner
should be operating and go off when controls are tested.
When safety controls are restored, burner should reignite.
Set Field Installed Thermostat
Heat Anticipator (if used)
• For single thermostat connected to T-T screw terminals
on low voltage terminal strip on control board of boiler,
set heat anticipator at 0.1 amps.
• For other wiring congurations, refer to instructions
provided by thermostat manufacturer regarding heat
anticipator adjustment.
• Cycle boiler with thermostat. Raise thermostat to
highest setting. Verify boiler goes through normal start
up cycle. Lower thermostat to lowest setting. Verify
boiler goes off.
Boiler Adjustment
1. Check incoming gas pressure to appliance using
pressure gauge with resolution of 0.1” w.c. or better
and range from 0” to at least 14” w.c.
2. Close gas shutoff inside boiler jacket.
3. Locate inlet pressure tap on gas valve. See Figure 1.
4. Open inlet pressure tap screw ½ turn.
5. Connect positive side of gauge to inlet pressure tap.
6. Open gas shutoff.
7. Gas pressure at high re should read between 4” and
10” w.c. for natural gas and between 10” and 14” w.c.
for LP gas.
6 - CHECKOUT PROCEDURES AND ADJUSTMENTS

10
6 - CHECKOUT PROCEDURES AND ADJUSTMENTS
Figure 2 Multimeter
8. Drill ½” hole in plastic CPVC vent pipe or exhaust
tee, just large enough to allow access for combustion
analyzer sample probe.
9. Turn thermostat to closed position so appliance is
activated.
10. Set appliance to high re mode as described in “User
Interface Quick Reference” section 10 page 21 and
allow it to run for approximately 5 minutes.
11. Insert sample probe of your combustion analyzer into
drilled hole from Step 8. Insert about halfway into
exhaust gas stream. Take ue gas reading and observe
% CO2and CO values. Adjust throttle screw until
correct readings are reached.
12. Turning throttle screw clockwise decreases rate and
CO2value. Turning throttle screw counter clockwise
increases rate and CO2 value.
13. Allow appliance to stabilize for one minute after
adjusting throttle screw before you take reading with
combustion analyzer.
NOTICE
CO levels should not exceed 80 ppm.
14. Set appliance to low re mode as described in “User
Interface Quick Reference” section. Check CO2level as
stated in Step 5. Low re and high re values should be
approximately same.
15. After adjustments are made stop appliance. Disconnect
pressure gauge, tighten inlet pressure tap on gas valve,
remove CO2meter from CPVC pipe, and seal hole with
¼” NPT black iron plug. Use thread sealing compound
or teon tape to ensure proper seal.
16. Return thermostat switch to its original position.
Measure Natural Gas Input Rate
1. Correct input rate is essential for proper and efcient
operation of burner and boiler.
2. Determine elevation at installation site.
3. See “Installation, Operation and Maintenance Manual”
to determine correct approximate input rate for local
elevation.
4. Obtain yearly average heating value of local gas utility.
At sea level elevation, it should be about 1000 BTU per
standard cubic foot.
5. Operate boiler for 5 minutes.
6. Turn off all other gas appliances, extinguishing standing
pilots where applicable.
7. At gas meter, measure time in seconds required to use
one cubic foot of gas.
8. Boiler must be in high re mode for this operation. See
“User Interface Quick Reference” section 10, for more
information on placing boiler in high re mode.
Calculate BTUH Input Rate as follows:
Btuh input rate = 3600 x heating value from Step 4
time in seconds
9. Measured input rate varies with vent length, gas
caloric content, altitude and ambient temperature.
Set boiler with combustion specications in “Boiler
Adjustment” section 6 page 9.
Determine Lp Gas Input Rate
Determine LP gas input rate by measuring C02produced
during combustion. Set this value according to guidelines
table on page 11.
Measure Flame Sense
Flame sense can be indicator of issues with air intake
venting, exhaust venting, burner and ignitor condition and
supply gas piping pressure.
Use multi meter capable of reading 0-20 VDC.
Attach one lead to “F” terminal on low voltage terminal
block on boiler control.
Attach other lead to any ground surface on boiler. See
Figure 2.
Flame sense voltage shall be in accordance with values
listed in Flame Signal Guidelines chart page 11.

11
Pressure Guidelines
Fan Speed Minimum RPM Maximum RPM
Fuel Natural Gas LP Natural Gas LP
Gas Line Inlet
Pressure N/A N/A At least 4” WC At least 10” WC
Differential Pres-
sure 0.3” WC 2.0” WC
Note: Differential pressure values listed for comparison only. These values will change with vent length
and altitude of installation.
Combustion Guidelines
Outside Natural Gas LP Gas
Temperature *%CO2*%O2CO *%CO2 *%O2CO
70°F and up 9.6% to
10%
3.9% to
3.2%
Less than
80 PPM
11.1% to
11.5%
4.1% to
3.4%
Less than
80 PPM
21°C and up
30°F to 70°F 9.3% to
9.6%
4.4% to
3.9%
Less than
80 PPM
10.8% to
11.1%
4.5% to
4.1%
Less than
80 PPM
-1°C to 21°C
30°F and below 9.0% to
9.3%
5.0% to
4.4%
Less than
80 PPM
10.5% to
10.8%
4.9% to
4.5%
Less than
80 PPM
-1°C and below
* PercentCO2valuesmayexceedthoselistedandpercentO2valuesmaybelessthanthoselistedinorder
toachievenominalinputrateofboiler.
Flame Signal Guidelines
Fan Speed Minimum RPM Maximum RPM
Flame Signal Greater than 3.0 VDC
Greater than 3.0 VDC
6 - CHECKOUT PROCEDURES AND ADJUSTMENTS

12
7 - DETAILED SEQUENCE OF OPERATION
POWER ON. UNIT IN STANDBY
THERMOSTAT CALLS FOR HEAT
INTERNAL MICRO CONTROLLER TEST
CIRCULATOR ENERGIZES
CONTROL CHECKS N O
AIR PRESSURE SWITCH
CONTACTS
COMBUSTION AIR
BLOWER ENERGIZES
CONTROL ENTERS
LOCKOUT ERROR CODE
DISPLAYED
CONTROL NEEDS
TO BE RESET FROM
LOCKOUT
CONTROL WAITS FOR
AIR PROVING SWITCHES
TO CLOSE INDICATING
SUFFICIENT FAN SUCTION
PRESENT
CONTROL ENTERS
LOCKOUT ERROR CODE
DISPLAYED
CONTROL NEEDS
TO BE RESET FROM
LOCKOUT
CONTROL ENTERS
PRE-PURGE
COMBUSTION AIR
BLOWER RUNS FOR 20
SECOND PRE-PURGE
SPARK IGNITER
ACTIVATES
GAS VALVE OPENS
UNIT LIGHTS AND
FLAME RECTIFICATION
UNIT TRIES FOR
IGNITION 5 TIMES
UNIT OPERATES
NORMALLY
FALSE POSITIVE PROOF
OF AIRFLOW
CONTROL ENTERS
LOCKOUT ERROR CODE
DISPLAYED
CONTROL NEEDS
TO BE RESET FROM
LOCKOUT
END CALL FOR HEAT
CONTROL ENTERS 30
SECOND POST PURGE
UNIT ENTERS
STANDBY, WAITING
FOR CALL FOR HEAT
CLOSED OPEN
CLOSED
OPEN
YES NO
ATTEMPT TO LIGHT
DOES NOT LIGHT AFTER 6 TRIES

13
Troubleshooting Tools
Tools needed for troubleshooting your boiler:
• Voltmeter that can check 120 VAC, 24 VAC, and 12
VDC
• Continuity Tester
• Contact Thermometer
• Inclined Manometer or Pressure Gauge with 0-6.0”
range (0.01” scale) for measuring suction pressures at
pressure switch
• U-Tube Manometer or Differential Pressure Gauge
with 0-14” range (0.1” scale) for measuring inlet and
manifold gas pressures
Initial Service Checks
Prior to troubleshooting:
1. Verify circuit breaker is ON or fuse is okay at electrical
panel.
2. Verify service switch is ON.
3. Verify 120 VAC (minimum 102 VAC to maximum 132
VAC) to boiler.
4. Verify thermostat is calling for heat and contacts
(including appropriate zone controls) are closed. Check
for 24 VAC between thermostat wire nuts and ground.
5. Verify all external limit controls are either installed (and
closed) or temporarily jumpered for testing.
6. Verify gas is ON at gas meter, at all appropriate manual
shutoff valves, and at gas control valve. Gas pressures
should be maximum of 10” w.c. (natural gas) or 14”
w.c. (for LP gas) with no ow (lockup) or with boiler on
and minimum of 5” w.c. with gas owing (verify during
boiler startup with boiler at high re).
7. Verify wire connectors at boiler control and at
originating control are securely plugged in or
connected.
8. Verify all hoses are securely connected and are not
plugged in or damaged.
8 - SERVICE HINTS
WARNING
Fire, Explosion, Shock Hazard. Revision,
modication, substitution or elimination of factory
equipped, supplied or specied components could
result in death or serious injury.
!
Important Service Information
• If any component does not function properly, make
sure it is correctly installed and wired before replacing
it.
• Static electricity discharge can damage the integrated
modulating boiler control (IMBC). Touch metal surface
to discharge static electricity before touching control.
• Boiler control cannot be repaired. If it malfunctions it
must be replaced.
• Only trained, experienced service technicians should
service boiler control systems.
• After troubleshooting, follow “Detailed Sequence of
Operation” Section 7 page 12, for normal light off
procedure.
• All controls are factory tested,a defective control is
generally least likely cause. If you suspect you have a
defective boiler control, read “Troubleshooting” Section
9 before you replace it.
• It is unlikely that two consecutive controls are
defective. Chances are that either there is nothing
wrong with the control or it is damaged by some other
problem (for example, an electrical short burning out a
transformer).

14
Differential Air Pressure
Differential air pressure switch is a safety device which
prevents boiler from ring if there is an air intake, boiler
heat exchanger or vent blockage.
To check differential air pressure:
1. Turn off service switch or lower thermostat setting.
2. Remove vinyl caps from tee.
3. Install testing lines as shown to inclined manometer
or differential pressure gauge with ability to read
0.01” increments to at least 6.0” w.c.
4. Turn on service switch and set thermostat to call for
heat.
Boiler Status Diff. Pressure Switch Contacts
Not Running 0” 3.5” Closed
0.14” Open
Running with
Blockage
Greater Than or
Equal To Setpoints
3.5” Open
0.14” Closed
Running w/out
Blockage (approx.)
Min. Fire: 0.3” 3.5” Closed
Max. Fire: 2” 0.14” Closed
If manometer readings do not correspond with chart
above, check for possible causes:
• Blockage or moisture in suction lines to switch.
• Blockage in air intake or vent pipes.
• Undersized air intake or vent pipes.
• Loose blower wheel on motor shaft.
• Incorrect pressure switch or pressure switch setpoint
When pressure reading is correct and pressure switch
is operating properly, remove testing lines and reinstall
vinyl caps to Tee and 3-way connector.
Checking the Differential Air Pressure
9 - TROUBLESHOOTING
DANGER
Electric shock hazard! Following procedures may
expose you to dangerous line voltage. Use caution
to avoid touching live electrical contacts. All service
must be performed by a trained, experienced service
technician. Failure to follow these instructions WILL
result in death or serious injury
!
CAUTION
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 gas supplier’s
instructions.
• If you cannot reach your gas supplier, call the re
department.
!
WARNING
Fire, Explosion. Shut off gas at a location external
to appliance should overheating occur or gas
supply fail to shut off. Do not turn off or disconnect
electrical supply to pump. Do not use the boiler
if any part of the gas control system has been
underwater.
Only a qualied service technician should inspect
the boiler and replace any part of control system
and any gas control which has been underwater.
Use only your hand to turn gas control knob. Never
use tools. If knob will not turn by hand, don’t try to
repair it.
Failure to follow these instructions could result in
death or serious injury.
!

15
Control Module Fuses
Check control module fuses before replacing control module
or any major components (blower, etc.) If one of these
fuses is blown, it can prevent control module or other
components from operating.
1. Turn OFF power to boiler at external line switch.
2. Remove jacket front panel.
3. Remove control module cover.
4. Inspect fuses F1 and F3 (shown below).
5. Boiler is shipped with four spare fuses attached to
control module cover.
6. If necessary, replace open fuse (F1 is 115V, 5-amp
fast-blow; F3 is 24V, 4-amp slow-blow).
7. Install control module cover and jacket top front cover
after fuse inspection.
8. Restore power to boiler at external line switch and
verify boiler operation after completing boiler service.
Checking Temperature Sensors
1. Boiler temperature sensors (outdoor, return water, and
supply water) are all resistance-type devices.
2. Table 1 shows correct resistance value for sensor at
various temperatures.
3. Use resistance values at 32°F, 60°F, 70°F and 212°F to
measure sensor resistance at known temperatures (ice
point, room temperature and sea level boiling point).
For ice point and boiling point, insert sensor in water
at that temperature. Use ohm meter to read resistance
value.
4. To verify control module is correctly sensing
temperature, use a resistance decade box. Connect
decade box temporarily in place of sensor. Use control
module “Information” mode to read temperature.
9 - TROUBLESHOOTING
DANGER
Electric shock hazard! Disconnect power before
servicing. All service must be performed by a
trained, experienced service technician. Never
jumper (bypass) any device except for momentary
testing as outlined on the following pages of this
manual. Failure to follow these instructions WILL
result in death or serious injury
!
F1 and F3 Fuses
Temp
°F
Sensor Ohms Temp
°F
Sensor Ohms
Min Max Min Max
32 34,265 37,871 130 3,698 4,088
40 27,834 30,764 140 3,043 3,364
50 21,630 23,907 150 2,517 2,782
60 16,944 18,727 160 2,091 2,311
70 13,372 14,780 170 1,744 1,928
80 10,629 11,747 180 1,461 1,615
90 8,504 9,399 190 1,229 1,359
100 6,847 7,568 200 1,038 1,147
110 5,545 6,129 210 880 972
120 4,517 4,992 212 851 941
Table 1 - Sensor Resistance Values at Various
Temperatures

16
Boiler Not Firing And: Check For: Step Corrective Actions:
Control display blank
120 vac at terminals L1 and L2 of line
voltage strip?
1 NO - Check external line switch and fuse or breaker.
2
Determine if red light on line voltage monitor is ashing
indication fault. If there is fault verify input voltage dial
is properly set in accordance with steps in installation
manual. If fault does not clear after ten minutes replace
line monitor.
120 vac on both sides of fuse F1? 1
NO - Turn off power to boiler and replace fuse if
necessary. Inspect boiler interior wiring to determine
cause of fuse opening.
Wiring correct, in good condition, and
securely attached? 1Correct if needed. Replace any damaged wiring or components. Replace control module if problem persists.
Display rst digit shows
0; last digits show 2 or
3-digit number (boiler
outlet water temp.)
Room thermostat and DHW aquastat
satised? 1YES - Boiler off, no call for heat. Turn up thermostat or aquastat. Boiler should start.
Thermostat or aquastat calling for heat
but boiler not ring.
1
Check voltage on both sides of low voltage fuse F3. (Turn
OFF external power before removing cover.) If necessary,
replace fuse. Determine reason for fuse failure if possible.
2Check/set boiler parameters 2 and 3. Make sure space
heat or DHW is turned on. Turn on if necessary.
3
Turn off power to boiler. Temporarily jumper low voltage
terminal strip terminals T1 and T2 or DHW T1 and
DHW T2. Retry. If boiler operates, check CH and DHW
thermostat and wiring. Replace if necessary. Remove
temporary jumper(s).
4Turn off power to boiler. Check wiring against wiring
diagram; verify all wiring in good condition and secure.
5 Replace wire harnesses and retry.
6 Replace control module.
Display rst digit shows number from 1 to 8; last digits show 2 or
3-digit number (boiler outlet water temp.) 1 Boiler in normal operating mode.
Display ashes “9,” then “b.” Last two digits show code number. 1
See UserInterfaceQuickReference and SoftLockout
Troubleshooting for more information on soft lockout code.
Display shows U 1.25
continuously
Transformer unplugged or not
functional
1 Plug transformer in.
2 Replace transformer.
F3 24V 4 Amp fuse is not functional 1 Replace fuse.
9 - TROUBLESHOOTING

17
SOFT LOCKOUT (Display ashes “9” and then “b” in rst position; last two digits on steady (code))
Code Reason For Soft Lockout Corrective Actions (pressing RESET should restart boiler immediately):
08 0.14” Pressure switch contacts
open 1Check pressure switch for proper operation. Replace pressure switch if moisture has entered switch. Check venting for blockage. Clear if present.
18
High Limit Operation: Burner
off until outlet water temperature
drops below 180 °F
1
Happen when heat demand is lower than lowest ring rate of boiler, such as
operation of single, small zone. Check system for:
• Verify boiler and system are full of water.
• Verify system does not have trapped air.
• Inspect and verify system piping and components.
• Verify piping agrees with boiler manual recommendations.
2
Use contact thermometer to check outlet water temp. Compare to temperature
shown with display in “INFO” mode (“1” in rst digit). Replace return temperature
sensor if results are not close. Replace control module if sensor replacement doesn’t
solve problem.
19
High Limit Operation: Burner
off until return water temp. drops
below 190 °F
1
Check system for:
• Verify boiler and system are full of water.
• Verify system does not have trapped air.
• Inspect and verify system piping and components.
• Verify water ow is not reversed or pipes crossed.
2
Use contact thermometer to check return water temp. Compare to temperature
shown with display in “INFO” mode (“2” in rst digit). Replace return temperature
sensor if results are not close. Replace control module if sensor replacement doesn’t
solve problem.
24 High Limit Operation: Return
temp. is higher than supply temp.
1
• Verify boiler and system are full of water.
• Verify system does not have trapped air.
• Inspect and verify system piping and components.
• Verify water ow is not reversed or pipes crossed.
2
Use contact thermometer to check return water temp. Compare to temperature
shown with display in “INFO” mode (“2” in rst digit). Replace return temp. sensor
if results are not close. Replace control module if sensor replacement doesn’t solve
problem.
25
High limit operation: Outlet
water temp. increased too quickly.
Non-adjustable default setting
9.8°F/sec
1
Indicates ow rate too low. Check system for:
• Verify boiler and system are full of water.
• Make sure system does not have trapped air.
• Inspect and verify system piping and components.
• Verify piping agrees with boiler manual recommendations.
2
Verify operation of boiler circulator:
• Check voltage at circulator junction box to ensure 120 vac when boiler
operates. If no voltage, check wiring and wiring connections.
• High voltage terminal strip terminals 5 and 6 should show 120 vac for space
heating; terminals 3 and 4 should show 120 vac for DHW. Replace circulator if
powered but not operating.
• Replace line voltage wire harness if necessary. Replace control module if wire
replacement doesn’t resolve.
26
Aquastat contacts open
or
LWCO contacts open
or
3.5” Switch open
1Verify proper setting of control.
Water temp too high, wait for temperature to drop below 180 degrees.
2
Check water level in boiler, ll if low.
Press LWCO reset switch on display panel
If problem still exists, check LWCO probe and board according to manufacturer’s
instructions. Replace if necessary.
3Check pressure switch for proper operation. Replace if moisture has entered switch.
Check venting for blockage. Clear if present.
9 - TROUBLESHOOTING

18
29 Blower turning when it should be
off. 1
Check boiler wiring against wiring diagram.
Replace line voltage and low voltage wiring harnesses if necessary.
Replace control module if wire replacement doesn’t resolve.
30
High limit operation:
Temperature rise across boiler too
high.
1
Flow rate too low.
Check system for:
Verify boiler and system are full of water.
Inspect and verify system piping and components.
Verify piping agrees with boiler manual recommendations.
Make sure system pressure drop is not too high.
2
Verify operation of boiler circulator.
Check voltage at circulator junction box to ensure 120 vac when boiler operates. If
no voltage, check wiring and wiring connections.
High voltage terminal strip terminals 5 and 6 should show 120 vac for space
heating; terminals 3 and 4 should show 120 vac for DHW.
Replace circulator if powered but not operating.
Replace line voltage wire harness if necessary.
Replace control module if wire replacement doesn’t resolve.
61 Pressure switch contacts closed. 1 Check pressure switches for proper operation.
Replace pressure switch if moisture has entered switch.
65 Blower not operating when turned
on.
1
Turn off power to boiler. Remove line voltage connector at blower. Restart boiler
and check voltage across blower plug terminals. If 120 vac is NOT present, inspect
wiring and tightness of connections.
Replace line voltage wire harness if necessary.
Replace control module if wire harness replacement doesn’t resolve.
2If 120 vac is present on blower wire harness, replace harness and retry. If problem
persists, replace blower motor.
9 - TROUBLESHOOTING

19
HARD LOCKOUT (Display ashes rst digit “E” and last two digits (code))
Code Reason For Hard Lockout Corrective Actions (pressing RESET should restart boiler immediately):
00 Flame detected on startup.
1
Burner may be operating too hot due to incorrect combustion. Inspect ame during
operation following procedure in this manual. If ame is acceptable at both high and
low re, go to step 2. If ame is not acceptable:
For propane boilers, verify propane orice is correct and properly installed. Obtain
and install propane orice if necessary.
For correct orice propane or natural gas boilers, replace gas valve if burner glows
excessively.
2
Look into the burner inspection window after the boiler shuts down. If ame is still
present, gas valve may be leaking. Replace gas valve. BEFORE replacing valve,
check gas line pressure coming to boiler. Pressure must not exceed 13” w.c. or valve
damage could occur.
02 Ignition failed through 5 attempts.
1
If no ignition spark occurs:
Check ignition electrode cable, electrode connector, and connections.
Inspect ignition electrode cable and electrode for insulation damage.
Check ground lead from ground terminal strip to heat exchanger access cover.
2
If spark occurs, but no ame:
Verify manual gas valve in boiler is open.
Verify plastic line from gas valve to air inlet elbow is connected to gas valve and
elbow, and line is unobstructed with no kinks.
Check incoming gas pressure.
Verify gas lines are free of obstruction and purge gas lines of air if necessary.
Verify ue gas vent and air supply piping are correctly installed, in good condition,
and free of obstructions.
Check voltage to gas valve (approx. 19-21 VDC (24 vrac) during ignition attempt).
Check gas meter to verify gas ows when gas valve is activated.
Remove and inspect/clean ignition electrode. Clean white oxides if necessary and
replace ignition electrode if in poor condition or unable to be cleaned.
Disconnect gas valve from Venturi. Inspect Venturi gas line to verify there are no
obstructions. Replace gas valve.
Check for possible ue gas recirculation at vent/air terminations or inside boiler
housing.
If gas valve is powered, gas ows when activated, and above steps have been
veried, replace gas valve and retry.
3
Flame occurs but ame signal too low (less than 3 vdc between X1-5 and ground):
Inspect ame at both low and high re rates. Inspect and clean burner if necessary.
Replace burner if not in good condition.
Check gas ow rate at gas meter with boiler at high re. If input is not within about
10% of boiler rating, replace gas valve. (Length of the vent/air piping will affect
boiler ring rate, with longer piping causing lower inputs.)
Check ground wire and connections from ground terminal screw to X1-6 terminal on
wiring harness. Use ground continuity meter to verify good ground path.
Follow procedure to inspect and clean ignition electrode. Replace ignition electrode if
necessary.
If above does not correct problem, replace control module.
03 Gas Valve Disconnected. 1 Verify gas valve connection.
04 Voltage lost after lockout occurred. 1 Control module will only restart with manual reset, even after power loss (but the
error code information is lost).
05
Internal control failure. 1 Reset control and retry. If problem persists, replace control module.
06
07
08
9 - TROUBLESHOOTING

20
HARD LOCKOUT (Display ashes rst digit “E” and last two digits (code))
Code Reason For Hard Lockout Corrective Actions (pressing RESET should restart boiler immediately):
WARNING: Electrical shock hazard. Turn off power to boiler when working with wiring or replacing any boiler component.
09 Internal control failure. 1 Reset control and retry. If problem persists, replace control module.
11
12 Casting temperature switch opened.
1Determine reason for limit action and correct. Check for air trapped at top of
casting.
2
If limits are closed, check wiring and connections. Apply a temporary jumper
across terminals 6 and 8 and check operation. If problem persists, check boiler
internal wiring. Replace low voltage harness if necessary. Replace control
module if harness replacement doesn’t resolve.
13 -
17 Internal control failure. 1 Reset control and retry. If problem persists, replace control module.
18 Thermal Overrun Condition:
Outlet water temp. above 200 °F
1
Check system for:
Verify boiler and system are full of water.
Make sure system does not have trapped air.
Inspect and verify system piping and components.
Make sure water ow is not reversed or pipes crossed.
2
Use contact thermometer to check outlet water temp. Compare to temp.
shown with display in “INFO” mode (“1” in rst digit). Replace return temp.
sensor if results are not close. Replace control module if sensor replacement
doesn’t solve problem.
19 Thermal Overrun Condition:
Return water temp. above 190 °F
1 See Code 18, Corrective Action#1 (above).
2
Use contact thermometer to check return water temp. Compare to temp.
shown with display in “INFO” mode (“2” in rst digit). Replace return temp.
sensor if results are not close. Replace control module if sensor replacement
doesn’t solve problem.
28 Blower not running.
1
Turn off power to boiler. Remove line voltage connector at blower. Restart
boiler and check voltage across blower plug terminals. If 120 vac is NOT
present, inspect wiring and tightness of connections. Replace line voltage
wire harness if necessary. Replace control module if wire harness replacement
doesn’t resolve.
2If 120 vac is present on blower wire harness, replace harness and retry. If
problem persists, replace blower motor.
29 Blower signal not 0 when it should
be. 1Inspect wiring and connections. If wiring is correct, replace blower assembly. If blower assembly replacement is unsuccessful, replace control module.
30
Temp difference between supply
& return, indicated by blocking
code b30, was too large for 20
successive times. Non adjustable
default Max Delta set to 100°F
1 Inspect supply & return water sensors for proper resistance.
2Inspect piping for proper conguration. For example, when used in a radiant
heating application.
31 Outlet water temp. short circuit. 1
Inspect outlet water temp. sensor and wiring. Replace sensor if wiring correct
and in good condition. Replace low voltage wiring harness if problem persists.
Replace control module if harness replacement doesn’t resolve.
32 Return water temp. short circuit. 1
Inspect return water temp. sensor and wiring. Replace sensor if wiring correct
and in good condition. Replace low voltage wiring harness if problem persists.
Replace control module if harness replacement doesn’t resolve.
36 Supply water temp. sensor open
circuit. 1 See Corrective Action# 1 under Code 31 (above)
37 Return water temp. sensor open
circuit. 1 See Corrective Action# 1 under Code 32 (above)
44
Internal control failure. 1 Rest control and retry. If problem persists, replace control module.
60
61
65 Blower signal too low (not enough
driving force). 1Inspect wiring and connections. If wiring is correct, replace blower assembly. If blower assembly replacement is unsuccessful, replace control module.
9 - TROUBLESHOOTING