Lochinvar 51-211 User Manual

WBII-SER Rev C

Service Manual

Models: 51 - 211

 WARNING

This manual must only be used
by a qualified heating installer
/ service technician. Read
all instructions, including
this manual and the Knight
Wall Mount Installation and
Operation Manual, before
installing. Perform steps in
the order given. Failure to
comply could result in severe
personal injury, death, or
substantial property damage.

Save this manual for future reference.

Contents

CONTENTS ........................................................................ 2

Hazard Definitions .............................................................. 2

PLEASE READ BEFORE PROCEEDING ......................... 3

Handling Ceramic Fiber Materials ...................................... 3

When servicing boiler ................................................... 4

Boiler operation ............................................................ 4

Boiler water ................................................................... 4

Freeze protection fluids ................................................ 4

WHAT IS IN THIS MANUAL .............................................. 5

1. SERVICE

Near Boiler Piping .............................................................. 6

The Knight Wall Mount Display .......................................... 7

Control Inputs ............................................................... 8

Control Outputs ............................................................. 9

General Operation ...................................................... 10

Sequence of Operation ............................................... 11-12

Display Panel Menu Access ............................................ 13

Display Panel Parameter Access ..................................... 14

Parameter Table.......................................................... 15-18

Viewable and Changeable Control Parameters .......... 19-27

Hazard definitions

2. MAINTENANCE

Maintenance and Annual Startup ................................ 28-32

3. TROUBLESHOOTING

Before Troubleshooting .................................................... 33

Check Control Module Fuses .......................................... 33

Table 3-1 - Troubleshooting Chart - No Display .............. 34

Checking Temperature Sensors ...................................... 35

Table 3-3 - Troubleshooting Chart - Noisy System ......... 36

Table 3-4 - Troubleshooting Chart - Fault Messages . 37-45

Combustion Analysis Procedure ...................................... 46

Table 3-5 - Troubleshooting Chart - Combustion Levels 46

Table 3-6 - Flue Products ................................................ 46

Gas Valve Adjustment Procedure .................................... 47

Revision Notes .................................................. Back Cover

The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk levels
or to important information concerning the life of the product.

 DANGER

 WARNING

 CAUTION

CAUTION

NOTICE

DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or serious
injury.

WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or serious
injury.

CAUTION indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate
injury.

CAUTION used without the safety alert symbol indicates a potentially hazardous situation which, if not
avoided, may result in property damage.

NOTICE indicates special instructions on installation, operation, or maintenance that are important but not
related to personal injury or property damage.

2

Please read before proceeding

Service Manual

 WARNING

Installer – Read all instructions,
including this manual and the Knight
Wall Mount Installation and Operation
Manual, before installing. Perform steps
in the order given.

User – This manual is for use only by
a qualified heating installer/service
technician. Refer to the Knight Wall
Mount User’s Information Manual for
your reference.

Have this boiler serviced/inspected by
a qualified service technician at least
annually.

Failure to comply with the above could
result in severe personal injury, death or
substantial property damage.

NOTICE

Handling ceramic fiber materials

REMOVAL OF COMBUSTION CHAMBER LINING

 WARNING

The combustion chamber insulation in this appliance contains ceramic fiber material. Ceramic fibers can
be converted to cristobalite in very high temperature applications. The International Agency for Research
on Cancer (IARC) has concluded, “Crystalline silica in the form of quartz or cristobalite from occupational
sources is carcinogenic to humans (Group 1).” Normal operating temperatures in this appliance are below
the level to convert ceramic fibers to cristobalite. Abnormal operating conditions would have to be created
to convert the ceramic fibers in this appliance to cristobalite.

When calling or writing about the boiler
– Please have the boiler model and serial
number from the boiler rating plate.

Consider piping and installation when
determining boiler location (see the Knight
Wall Mount Installation and Operation
Manual).

Any claims for damage or shortage
in shipment must be filed immediately
against the transportation company by the
consignee.

The ceramic fiber material used in this appliance is an irritant; when handling or replacing the ceramic
materials it is advisable that the installer follow these safety guidelines.

Avoid breathing dust and contact with skin and eyes.

• Use NIOSH certified dust respirator (N95). This type of respirator is based on the OSHA
requirements for cristobalite at the time this document was written. Other types of respirators may
be needed depending on the job site conditions. Current NIOSH recommendations can be found on
the NIOSH website at http://www.cdc.gov/niosh/homepage.html. NIOSH approved respirators,
manufacturers, and phone numbers are also listed on this website.

• Wear long-sleeved, loose fitting clothing, gloves, and eye protection.

Apply enough water to the combustion chamber lining to prevent airborne dust.

 Remove the combustion chamber lining from the appliance and place it in a plastic bag for disposal.

 Wash potentially contaminated clothes separately from other clothing. Rinse clothes washer

thoroughly.

NIOSH stated First Aid.

 Eye: Irrigate immediately.
 Breathing: Fresh air.

3

Please read before proceeding

When servicing boiler –

• To avoid electric shock, disconnect electrical supply
before performing maintenance.

• To avoid severe burns, allow boiler to cool before
performing maintenance.

Boiler operation –

• Do not block flow of combustion or ventilation air to
the boiler.

• Should overheating occur or gas supply fail to shut off,
do not turn off or disconnect electrical supply to
circulator. Instead, shut off the gas supply at a location
external to the appliance.

• Do not use this boiler if any part has been under water.
The possible damage to a flooded appliance can be
extensive and present numerous safety hazards. Any
appliance that has been under water must be replaced.

Service Manual

Boiler water –

• Thoroughly flush the system (without boiler
connected) to remove sediment. The high-efficiency
heat exchanger can be damaged by build-up or
corrosion due to sediment.

• Do not use petroleum-based cleaning or sealing
compounds in the boiler system. Gaskets and seals in
the system may be damaged. This can result in
substantial property damage.

• Do not use “homemade cures” or “boiler patent
medicines”. Serious damage to the boiler, personnel,
and/or property may result.

• Continual fresh make-up water will reduce boiler life.
Mineral buildup in the heat exchanger reduces heat
transfer, overheats the stainless steel heat exchanger, and
causes failure. Addition of oxygen carried in by makeup
water can cause internal corrosion. Leaks in boiler
piping must be repaired at once to prevent the
introduction of makeup water.

Freeze protection fluids –

• NEVER use automotive antifreeze. Use only inhibited
propylene glycol solutions which are specifically
formulated for hydronic systems. Ethylene glycol is
toxic and can attack gaskets and seals used in hydronic
systems.

4

What is in this manual?

Service Manual

Service

Near boiler piping

• Typical system components

The Knight wall mount boiler display

• Display panel readout, buttons and their functions

Control module inputs

• Control module inputs and options

Control module outputs

• Control module outputs and options

General

• How the boiler operates

• How the control module operates

• Access modes -- user and installer

• Sequence of operation -- Domestic Hot Water
(DHW)/space heating

Control panel menu access

• Accessing programming mode and locating menus
(See separate guide covering the PC interface.)

Control panel parameter access

• Accessing and changing parameters from the display panel

Quick start information -- parameter
table

• An index of available adjustments and readouts, where to
access them and where to find detailed information.

Knight wall mount boiler operation

• A: General

• B: Temperature Setting

• C: Data Logging

• D: Functions

• E: DHW Settings

• F: Outdoor Reset

• G: Anti-cycling

• H: Control Modes

• I: Circulation Pumps

• J: Building Management System (BMS)

• K: Service Notification

Maintenance

• Service and maintenance schedules

• Address reported problems

• Inspect boiler area and boiler interior

• Clean condensate trap

• Check all piping for leaks

• Check air openings

• Flue vent system and air piping

• Check water system

• Check expansion tank

• Check boiler relief valve

• Inspect ignition electrode

• Check ignition ground wiring

• Check all boiler wiring

• Check control settings

• Perform start-up and checks

• Check burner flame

• Check flame signal

• Check flue gas temperature

• General maintenance

• Review with owner

• Cleaning boiler heat exchanger

• Oiled bearing circulators

Troubleshooting

• Troubleshooting table - No display

• Checking temperature sensors

• Sensor tables

• Troubleshooting table - Fault messages displayed on
boiler interface

• Combustion analysis procedure

• Gas valve adjustment procedure

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1 Service

Near boiler piping

This piping reference is included to specify the Near Boiler Piping specific to the Knight wall mount boiler. This piping scheme
is important for proper operation of the SMART SYSTEM control. See the Knight Wall Mount Installation and Operation
Manual for more detailed piping diagrams.

CONDENSATE

DRAIN

BOILER
PUMP

VENT

AIR

FROM

TO

DOMESTIC
HOT WATER
PUMP

INDIRECT
DOMESTIC
HOT WATER
TANK

M

E

T

S

Y

S

O

T

TO FLOOR

Y-S TRAINER

(RECOMMENDED)

MSY

O

R

F

6

DRAIN

M

E

ST

SYSTEM

PUMP

SYSTEM
SENSOR

AIR

SEPARATOR

EXPANSION TANK

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1 Service (continued)

The Knight wall mount display

Service Manual

NAVIGATION DIAL

The information on the bottom of the display shows the functions of the two SELECT keys (on either corner), and the
NAVIGATION dial (in the center):

MENU = Left SELECT Key
SETPOINTS = NAVIGATION Dial - Pressing Down
SHDN = Right SELECT Key

7

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1 Service

Control inputs

SYSTEM PUMP SPEED CONTROL

GAS PRESSURE SWITCH

DHW THERMOSTAT

ROOM THERMOSTAT /

ZONE CONTROL

SYSTEM SENSOR

FLOW SW ITCH

Service Manual

LOW VOLTAGE

CONNECTION

BOARD

OUTDOOR SENSOR

BUILDING MANAGEMENT

SYSTEM

LOW WATER CUTOFF

INLET TEMPERATURE

SENSOR

OUTLET TEMPERATURE /

HIGH LIMIT SENSOR

FLUE GAS SENSOR

PRESSURE SWITCH

FLAME SENSOR

BLOCKED DRAIN SWITCH

PC INTERFACE

8

SMART CONTROL

MODULE

DISPLAY PANEL

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1 Service (continued)

Control outputs

Service Manual

ALARM BELL

LOW VOLTAGE

CONNECTION

BOARD

AUX. DEVICE RELAY

RUN TIME CONTACTS

BUILDING MANAGEMENT

SYSTEM

BOILER PUMP

SYSTEM PUMP

DHW PUMP

SMART CONTROL

MODULE

IGNITOR

BLOWER

GAS VALVE

DISPL AY PANE L

PC INTERFACE

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General Operation

Service Manual

How the boiler operates

The Knight wall mount boiler uses an advanced stainless steel
heat exchanger and an electronic control module that allows
fully condensing operation. The blower pulls in gas and air
and pushes flue products out of the boiler through the heat
exchanger and flue piping. The control module regulates
blower speed to control boiler firing rate. The gas valve
senses the amount of air flowing into the boiler and allows
only the right amount of gas to flow.

How the control module operates

The Knight wall mount control module receives input from
boiler sensors. The control module activates and controls
the blower and gas valve to regulate heat input and switches
boiler, DHW and system pumps on and off as needed. The
user/installer programs the module to meet system needs by
adjusting control parameters. These parameters set operating
temperatures and boiler operating modes. Boiler operation
can be based on boiler outlet water temperature, boiler return
water temperature or system supply temperature, depending
on the parameter setting.

Access modes

User

The user can adjust space heating and tank target temperatures
by pressing the NAVIGATION dial when “SETPOINTS” is
flashing at the bottom of the display. The date and time, and
the temperature units can also be changed.

Installer

Most parameters are available only to the installer, accessible
only by entering the installer password, see the Knight Wall
Mount Service Manual.

Saving parameters (reference the Parameter Table -

Table 1-4 on pages 15 - 18 of this manual)

NOTICE

To save parameters and exit programming:

Press the RIGHT SELECT [SAVE] key and then press the
RIGHT SELECT [HOME] key.

Please note that the brackets ([]) denote
screen status.

Sequence of operation

Table 1-1 shows control module normal sequences of
operation for space heating and DHW operation. The
combined operation sequence is for a typical application,
programmed to provide DHW priority.

To enter a parameter and continue programming:

Press the RIGHT SELECT [SAVE] key 1 time to return to the
parameter listings; press again to return to the menu listings.
Remember to press the RIGHT SELECT [HOME] key when
finished programming in order to save the changes made.

10

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Sequence of operation

OPERATION DISPLAY

1. Upon a call for heat, the gas pressure switch(es) must be closed.

2. Once the gas pressure switch(es) are closed, the control turns
on the appropriate pumps (system and boiler pumps for space
heating, DHW pump for DHW). The flow switch and/or LWCO
must close.

Service Manual

3. The control turns on power to the louver relay. The louver
proving switch, air pressure switch, and blocked drain switch
must close.

4. The control starts a 15 second prepurge cycle by initiating the

blower.

5. The control starts a 4 second trial for ignition by firing the spark

electrode and opening the gas valve.

6. If flame is not detected within 1 second after the sparking ends,

the control will perform a 10 second post-purge, then start
another prepurge cycle and try to light the burner again. The
control will perform a total of 4 attempts before locking out.

7. If flame is detected, it holds the firing rate steady for 5 seconds
to let the flame stabilize, then it begins to modulate the firing rate
based on a set point or some other command (such as a 0-10V
BMS signal).

11

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1 Service

Sequence of operation (continued)

OPERATION DISPLAY

8. If the space heating call for heat is active, and the tank thermostat
or sensor starts a DHW call for heat, the boiler will switch to the
DHW mode. If programmed for normal DHW operation (not as a
zone), the DHW pump will turn on first, then the boiler pump will
turn off 2 seconds later. This will divert the boiler’s outlet water
from the heating system and send it to the tank coil instead. The
control will then modulate to maintain the outlet temperature to
the DHW boiler set point.

9. If the boiler is not part of a Cascade, and both the space heating
and DHW calls for heat remain active long enough, the boiler will
switch back and forth between the two heating modes until one
of them is satisfied.

Service Manual

10. Once both calls for heat are satisfied, the control will turn off the
burner. The blower will continue to run during a 10 second
postpurge.

11. Any pumps that are running will continue to run for their
respective pump delay times before turning off, unless
programmed to remain on continuously. A 60 second anti-cycle
period will start, which will delay any new call for heat until it
times out.

12. In Standby, ready to start a new cycle.

12

Service Manual

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1 Service (continued)

Display panel menu access

Table 1-2 Use this procedure to access menus from the display panel

BUTTON

SCREEN
STATUS

[SHDN] Press the RIGHT SELECT soft key [SHDN].

[YES] Press the LEFT SELECT soft key [YES].

[MENU]

Press and hold the LEFT SELECT soft key [MENU]
for five (5) seconds.

Rotate the NAVIGATION dial clockwise until 5 is
displayed (first digit on the left).

OPERATION DISPLAY

Press the NAVIGATION dial to select the next digit.
Rotate the NAVIGATION dial clockwise until 3 is
shown in the display.

Press the NAVIGATION dial 2 times to move to the last
digit. Rotate the NAVIGATION dial counterclockwise
until 9 is displayed.

[SAVE] Press the RIGHT SELECT soft key [SAVE].

Rotate the NAVIGATION dial counterclockwise to
select a category.

13

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1 Service

Display panel parameter access

Table 1-3 This is a typical example of accessing a parameter, shown for parameter Temperature Settings, MIN
SH Setpt

BUTTON

This example shows how to access parameter Temperature Settings. The first display shown is at the beginning
of the menu listings, after entering the installer access code.

SCREEN
STATUS

OPERATION DISPLAY

Rotate the NAVIGATION dial counterclockwise until
the arrow (>) is next to TEMPERATURE SETTINGS.

Press the NAVIGATION dial one time.

Rotate the NAVIGATION dial counterclockwise until
the arrow (>) is next to MIN SETPT.

Press the NAVIGATION dial one time.

14

Rotate the NAVIGATION dial to the desired
temperature.

[SAVE] Press the RIGHT SELECT soft key [SAVE] one time.

[EXIT]

[HOME] Press the LEFT SELECT soft key [HOME].

Press the LEFT SELECT soft key [EXIT] if all desired
changes have been made.

Service Manual

1 Service

1 Service (continued)

Parameter table

Table 1-4 This table lists SMART SYSTEM control module parameters and where to access them

Menu Description

Time and Date 19 Yes Yes Yes Yes
Software Version (read only) 19 No No Yes No
Temperature Units (ºC/ºF) 19 Yes Yes Yes Yes
SH Night Setback Offset 19 No No Yes Yes
SH Night Setback On Times 19 No No Yes Yes
SH Night Setback Off Times 19 No No Yes Yes

GENERAL

DHW Night Setback Offset 19 No No Yes Yes
DHW Night Setback On Times 19 No No Yes Yes
DHW Night Setback Off Times 19 No No Yes Yes
Night Setback Override 19 Yes Yes Yes Yes
Display Timeout 20 No No Yes Yes
SH1 Set Point 20 Yes Yes No No
Minimum SH Set Point 20 No No Yes Yes

See

Page

User Access Installer Access

Display Modify Display Modify

Maximum SH Set Point 20 No No Yes Yes
SH1 Offset 20 No No Yes Yes
SH1 Differential 20 No No Yes Yes
SH2 Set Point 20 Yes Yes No No
SH2 Offset 20 No No Yes Yes
SH2 Differential 20 No No Yes Yes

TEMPERATURE SETTINGS

SH3 Set Point 20 Yes Yes No No
SH3 Offset 20 No No Yes Yes
SH3 Differential 20 No No Yes Yes

DATA

LOGGING

Reset Log Errors 20 No No Yes Yes

Service Mode Delay 20 No No Yes Yes
Freeze Protection Pump On 20 No No Yes Yes
Freeze Protection Burner On 20 No No Yes Yes

FUNCTIONS

Freeze Protection Burner Differential 20 No No Yes Yes

15

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1 Service

Parameter table

Table 1-4 (continued from previous page) This table lists SMART SYSTEM control module parameters and where
to access them

Menu Description

DHW Boiler Set Point 21 No No Yes Yes
Tank Set Point 21 Yes Yes Yes Yes
Tank Set Point Differential 21 No No Yes Yes
DHW Boiler Offset 21 No No Yes Yes
DHW Boiler Differential 21 No No Yes Yes
SH/DHW Switching Time 21 No No Yes Yes
DHW/SH Switching Time 21 No No Yes Yes

DHW SETTINGS

Tank Minimum Set Point 21 No No Yes Yes
Tank Maximum Set Point 21 No No Yes Yes
DHW Type 21 No No Yes Yes

Fan Speed Limiting for DHW 21 No No Yes Yes
Outdoor 1 Low 22 No No Yes Yes
Outdoor 1 High 22 No No Yes Yes
Set Point 1 at Low Outdoor Temp 1 22 No No Yes Yes
Set Point 1 at High Outdoor Temp 1 22 No No Yes Yes

See

Page

User Access Installer Access

Display Modify Display Modify

Outdoor Air Shutdown SH1 22 No No Yes Yes
Outdoor Air Shutdown Differential SH1 23 No No Yes Yes
Shift Reset Curve SH1 23 No No Yes Yes

Outdoor 2 Low 22 No No Yes Yes
Outdoor 2 High 22 No No Yes Yes
Set Point 2 at Low Outdoor Temp 2 22 No No Yes Yes

Set Point 2 at High Outdoor Temp 2 22 No No Yes Yes
Outdoor Air Shutdown SH2 22 No No Yes Yes
Outdoor Air Shutdown Differential SH2 23 No No Yes Yes

OUTDOOR RESET

Shift Reset Curve SH2 23 No No Yes Yes
Outdoor 3 Low 22 No No Yes Yes
Outdoor 3 High 22 No No Yes Yes
Set Point 3 at Low Outdoor Temp 3 22 No No Yes Yes
Set Point 3 at High Outdoor Temp 3 22 No No Yes Yes
Outdoor Air Shutdown SH3 22 No No Yes Yes
Outdoor Air Shutdown Differential SH3 23 No No Yes Yes

16

Shift Reset Curve SH3 23 No No Yes Yes

Service Manual

1 Service (continued)

Parameter table

Table 1-4 (continued from previous page) This table lists SMART SYSTEM control module parameters and where
to access them

Menu Description

Boost Temperature 23 No No Yes Yes

RESET

Boost Time 23 No No Yes Yes

OUTDOOR

Anti-Cycling Time 23 No No Yes Yes
Anti-Cycling Override Differential 23 No No Yes Yes
Ramp Delay 23 No No Yes Yes
Ramp Settings 24 No No Yes Yes

ANTI-CYCLING

Controlling Sensor 24 No No Yes Yes
BMS Tstat Input 24 No No Yes Yes
BMS 24 No No Yes Yes
ModBus 25 No No Yes Yes
ModBus T/O 25 No No Yes Yes
Cascade Address 25 No No Yes Yes

See

Page

User Access Installer Access

Display Modify Display Modify

Cascade Type 25 No No Yes Yes
Max Cascade Set Point 25 No No Yes Yes

CONTROL MODES

Cascade Offset 25 No No Yes Yes
Cascade Differential 25 No No Yes Yes
Min On/Off Time 25 No No Yes Yes
Min Next On Time 25 No No Yes Yes
System Pump Delay 26 No No Yes Yes
Boiler Pump Delay 26 No No Yes Yes
DHW Pump Delay 26 No No Yes Yes
Boiler Pump Anti-Seize Delay 26 No No Yes Yes
Boiler Pump Min Voltage 26 No No Yes Yes
System Pump Type 26 No No Yes Yes
DHW Pump Anti-Seize Delay 26 No No Yes Yes

CIRCULATION PUMPS

System Pump Anti-Seize Delay 26 No No Yes Yes

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Parameter table

Table 1-4 (continued from previous page) This table lists SMART SYSTEM control module parameters and where
to access them

Menu Description

BMS Type 26 No No Yes Yes
Volts at Min 26 No No Yes Yes
Volts at Max 26 No No Yes Yes
Rate at Min Volts 26 No No Yes Yes
Rate at Max Volts 26 No No Yes Yes

BMS

Set Point at Min Volts 27 No No Yes Yes
Set Point at Max Volts 27 No No Yes Yes
On Volts 27 No No Yes Yes
Off Differential Volts 27 No No Yes Yes
Service Notification Months 27 No No Yes Yes
Service Notification Running Time 27 No No Yes Yes
Service Notification Cycles 27 No No Yes Yes

SERVICE

Reset Maintenance Reminder 27 No No Yes Yes

NOTIFICATION

Service Name and Phone Number 27 No No Yes Yes

See

Page

User Access Installer Access

Display Modify Display Modify

18

Service Manual

1 Service (continued)

Viewable and changeable control parameters

CAUTION

Before changing parameters, note the
settings so that the unit can be returned to
its original operating parameters.

General

Time and Date

The control uses an internal clock for the night setback
feature and for logging of events. For these features to
work correctly, the clock must be set when the boiler is first
installed or anytime the boiler has been powered off for more
than four (4) hours. This parameter must be accessed to set
the clock.

NOTICE

Software Version

The software version allows the user to view the software
version in use by the control. This software controls the
operation of the boiler. When a new software version
becomes available, the existing control can be replaced with a
new control to update the software.

Software version is read only.

Temperature units (°C / °F)

The control can be configured to display temperature in
either °C or °F. This parameter can be changed by the user
or the installer by accessing the Temperature Units parameter.
The default is °F.

Space Heating (SH) and Domestic Hot Water (DHW)
Night Setback Offset

Once the unit’s internal clock has been set correctly, the
Night Setback feature can be used to program a lower set
point during unoccupied times. Both the space heating and
DHW can be programmed for night setback. When in night
setback, the control reduces the set point by a fixed amount.
For space heating, it subtracts the space heating night setback
offset from each of the SH user set points (SH1, 2, and 3 Set
point parameters), or the calculated outdoor reset set point (if
lower). For DHW, it subtracts the DHW night setback offset
from the tank set point (Tank Set point parameter).

NOTE: The DHW night setback will not work without a tank
sensor installed.

The installer may adjust the space heating night setback
offset by accessing the SH Night Setback Offset parameter and
the DHW night setback offset by accessing the DHW Night
Setback Offset parameter. The minimum setting is 0°F (0°C)
and the maximum setting is 90°F (50°C).

The internal clock does not adjust for
Daylight Savings Time and therefore,
will require a manual adjustment.

Space Heating (SH) and Domestic Hot Water (DHW)
Night Setback On Times

This is the time in which the SH Night Setback Offset becomes
active. There are 7 start times and 7 stop times each for the
space heating and DHW night setback features. Both may be
set to any time within a 7-day week. These settings are referred
to as triggers. Multiple start or stop triggers may be set within a
single day, if desired. When a start trigger and a stop trigger are
set to the same time, the stop trigger has priority. The installer
may adjust the space heating night setback start triggers by
accessing the SH Night Setback On Times parameter. The DHW
start triggers in the DHW Night Setback On Times parameter.
This screen shows the start trigger number, the day of the week,
and the time of day.

NOTICE

1. When the screen is first accessed, start trigger number 1
is shown. If a different trigger number is desired, the
installer can rotate the NAVIGATION dial until the
desired trigger number is displayed. Once the desired trigger
number is selected, the installer can press the NAVIGATION
dial and the day of the week will start to flash.

2. The installer can adjust the day of the week to the one he
wishes to set. Once the day is set, the installer can press the
NAVIGATION dial and the hour will begin to flash.

3. After setting the hour, the installer can press the
NAVIGATION dial and the minutes will flash. Once all
settings have been made, the installer can press the RIGHT
SELECT [SAVE] key. The installer can now select a
different trigger and adjust the settings for that trigger.

4. Once all adjustments are made, the installer can press the
RIGHT SELECT [SAVE] key to save all of the new settings
and return to the General menu, or press the LEFT SELECT
[EXIT] key to return to the General menu without saving the
changes.

Space Heating (SH) and Domestic Hot Water (DHW)
Night Setback Off Times

The corresponding space heating night setback stop triggers are
set by accessing the SH Night Setback Off Times parameter. The
stop triggers for the DHW night setback feature can be adjusted
by accessing the DHW Night Setback Off Times parameter. The
adjustment procedure for these parameters is identical to the
space heating start triggers described above.

Night Setback Override

Any Night Setback On trigger currently active or scheduled
within the next seven (7) days can be skipped. To skip a trigger,
press the MENU key for 5 seconds, enter the user password,
and press the SAVE key. Rotate the NAVIGATION dial to NSB
OVERRIDE, and press the NAVIGATION dial. A list of the
current (if active) and upcoming NSB On triggers will appear.

Please note that the brackets ([]) denote
screen status.

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Service Manual

Rotate the NAVIGATION dial to select the trigger you wish
to skip and press the NAVIGATION dial. “SK” will appear
next to that trigger. You can rotate the NAVIGATION dial
again to select another trigger if you wish. If you wish to
reinstate a skipped trigger, re-select that trigger and press
the NAVIGATION dial again. The “SK” next to that trigger
will disappear. Press the HOME key to save these skipped
triggers. If you selected any currently active trigger(s), the
current Night Setback will be cancelled.

Display Timeout

This is the time in which the display remains illuminated.
The range is 10 seconds to 10 minutes. The default is 3
minutes.

Temperature Settings

Space Heating (SH1, SH2, SH3) Set Point

CAUTION

There are three (3) individual user set points for better zone
control. These are listed as SH1 Set Point through SH3 Set
Point. If multiple set points are calling for heat the highest set
point has priority. The range is SH Minimum Set point to SH
Maximum Set point. The default is 125°F (52°C).

Space Heating (SH) Minimum Set Point

The SH minimum set point sets the minimum water
temperature set point that can be used for space heating
operation. The user or installer will not be able to program
the control with a lower SH set point. This parameter can
only be changed by the installer by accessing Minimum SH
Set point parameter. The temperature range of this parameter
is 32°F (0°C) to the space heating maximum set point. The
default value is 32°F (21°C).

Space Heating (SH) Maximum Set Point

The SH maximum set point sets the maximum water
temperature set point that can be used for space heating. The
user or installer will not be able to program the control with a
higher SH set point. This parameter can only be changed by
the installer by accessing Maximum SH Set point parameter.
The temperature range of this parameter is the space heating
minimum set point to 180°F (82°C). The default value is
180°F (82°C).

SH1 - SH3 Offset Set Point

The SH offset sets how many degrees above set point the
temperature has to go before the boiler will shut off. This
parameter can only be changed by the installer by accessing
parameters SH1, 2 and 3 Offset Set point parameters. The
temperature range of these parameters is 0°F to 20°F. The
default value is 10°F.

Mixing valves are required for the
protection of any low temperature loops.

20

SH1 - SH3 Differential Set Point

The SH differential sets how many degrees below the offset
the temperature has to drop before the boiler turns back
on. This parameter can only be changed by the installer by
accessing the SH1, 2 and 3 Differential Set point parameters.

The range is 0°F to 60°F. The default is 20°F.

Data Logging

Reset log errors

The reset log errors function clears the last 10 errors log.

Functions

Service Mode Delay

By pressing the pin button on the front of the display for
five (5) seconds, the control will be placed in Service Mode.
This will override all other heat demands. The Service Mode
allows the installer to set the unit to any firing rate for the
purpose of combustion analysis. The delay sets the length of
time the boiler will stay in the Service Mode if no keys have
been pressed before going back to its original state. This
parameter can only be changed by the installer by accessing
the Service Mode Delay parameter. The time range of this
parameter is 1 to 10 minutes. The default value is 10 minutes.

Freeze Protection Pump On

The SMART SYSTEM control will turn on the boiler and
system pump outputs whenever the inlet temperature drops
below this setting. This is done to prevent the water in the
heat exchanger from freezing. Certain low-temperature
applications (such as snow melt) can operate at temperatures
around freezing, so this setting needs to be lowered in these
cases. The installer can adjust the temperature at which the
pump outputs are turned on by accessing Freeze Protection
Pump On parameter. The minimum setting is -3°F (-19°C),
and the maximum setting is 45°F (7.2°C). The default setting
is 45°F (7.2°C).

NOTICE

Freeze Protection Burner On

If running the pumps does not prevent the inlet temperature
from falling closer to freezing, the SMART SYSTEM control
will fire the burner at low fire. The installer can adjust the
temperature at which the burner fires by adjusting the Freeze
Protection Burner On parameter. The minimum setting is

-3°F (-19°C), and the maximum setting is 45°F (7.2°C). The
default setting is 37°F (2.8°C).

NOTICE

Freeze Protection Burner Differential

Once the burner has started firing due to a low inlet
temperature, the inlet temperature must increase by this
amount before the burner turns back off. The installer can
adjust this differential by accessing the Freeze Protection
Burner Differential parameter. The minimum setting is 0°F,
and the maximum is 20°F. The default setting is 5°F (2.8°C).

Never put the Freeze Protection Pump
on a setting lower than the Freeze
Protection Burner On setting.

Never put the Freeze Protection Pump
on a setting lower than the Freeze
Protection Burner On setting.

1 Service (continued)

Service Manual

DHW Settings

DHW Boiler Set Point

When a DHW call for heat becomes active, the control will
use the DHW boiler set point to determine the firing rate of
the boiler based on the boiler outlet water temperature, or
system temperature when DHW is programmed as a zone.

This parameter can be changed by the installer by accessing
the DHW Boiler Set point parameter. The temperature range
of this parameter is 68°F (20°C) to 180°F (82°C). The default
value is 180°F (82°C).

DHW Tank Set Point

By installing a tank sensor, the SMART SYSTEM control can
perform the tank thermostat function. The SMART SYSTEM
control automatically detects the presence of this sensor, and
generates a DHW call for heat when the tank temperature
drops below the tank set point differential (Tank Set point
Differential parameter), and finishes the call for heat when
the tank temperature reaches tank set point + offset. This
parameter can be changed by the installer by accessing the
DHW Tank Set point parameter. The temperature range of
this parameter tank minimum set point to tank maximum set
point. The default value is 125°F (52°C).

Tank Set Point Differential

When a tank sensor is installed, the tank temperature must
drop this amount below the tank set point (DHW Tank
Set point parameter) before the boiler turns back on. The
installer can adjust this setting by accessing the Tank Set point
Differential parameter. The minimum setting is 0° (0°C), and
the maximum is 40°F (22°C). The default setting is 6°F (3°C).

DHW Boiler Offset

This parameter reflects the degrees above DHW boiler set
point the temperature has to go before the boiler will shut off.
The range is 0°F (0°C) to 40°F (22°C). The default setting is
10°F (6°C).

DHW Boiler Differential

This parameter reflects the degrees below DHW boiler set
point the temperature has to go before the boiler turns back
on. The range is 0°F (0°C) to 60°F (33°C). The default setting
is 20°F (13°C).

SH/DHW Switching Time

When a boiler has a space heating demand and it receives
a DHW demand, it will immediately switch to the DHW
demand and start a timer. Once the timer has expired, the
boiler will switch back to the space heating demand and start
another timer. Once this timer expires, it will switch back to
the DHW demand. The installer can adjust the length of time
the boiler will service the space heating demand by accessing
SH/DHW Switching Time parameter. The minimum setting
is 0 minutes and the maximum setting is 50 minutes. The
default time is 30 minutes.

DHW/SH Switching Time

When a boiler has a DHW demand and it receives a space
heating demand, the SMART SYSTEM control will start a
timer. Once the timer expires, it will stop the DHW demand
and service the space heating demand. The installer can adjust
the length of time the boiler will service the DHW demand
by accessing the DHW/SW Switching Time parameter. The
minimum setting is 0 minutes and the maximum setting is 50
minutes. The default setting is 30 minutes.

Tank Minimum Set Point

This setting controls the minimum tank set point for the tank
temperature. The installer can adjust this by accessing the Tank
Minimum Set point parameter. The minimum setting is 60°F
(16°C) and the maximum setting is the maximum tank set point
(Tank Maximum Set point parameter). The default value is 60°
(16°C).

Tank Maximum Set Point

This setting controls the maximum tank set point for the tank
temperature. The installer can adjust this by accessing the Tank
Maximum Set point parameter. The minimum setting is the
minimum tank set point (Tank Minimum Set point parameter)
and the maximum setting is 190°F (88°C). The default value is
140°F (60°C).

DHW Type

This parameter determines whether the Knight wall mount
boiler treats the indirect DHW tank as a separate load, or as a
zone on the primary loop. When programmed as a separate
load, the boiler will turn on the DHW pump and then turn off
the boiler pump when an indirect DHW demand begins. When
programmed as a zone, the boiler will turn on the DHW pump,
leave the boiler pump on and change the system set point to the
DHW boiler set point (DHW Boiler Set point parameter).

This setting may be changed by the installer by accessing the
DHW Type parameter. The choices are NORMAL and ZONE.
The default setting is NORMAL.

Fan Speed Limiting for Indirect DHW Tank

This parameter determines the maximum fan speed (and
therefore the maximum rate) to be used when heating an
indirect DHW tank. This setting may be used when the tank is
unable to accept all of the BTU’s available from the boiler. This
parameter may be adjusted by the installer by accessing the Fan
Speed Limiting for Indirect DHW Tank parameter. The default
value is the maximum fan speed for that model.

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Outdoor Reset

The option of controlling up to three (3) different outdoor
resets for low outdoor temperatures is available.

Outdoor (1 - 3) Low

When the outdoor air temperature drops to this point, the
water temperature will be at the Set point 1 at Low Outdoor

Temp 1, Set point 2 at Low Outdoor Temp 2 and Set point
3 at Low Outdoor Temp 3 parameters (FIG. 1-1). If the

outdoor air temperature drops further, the set point will
continue to increase above this setting. This parameter can
be changed by the installer by accessing the Outdoor (1-3)
Low parameter. The temperature range of this parameter is

-39°F (-39°C) to high outdoor temperature set point. The
default value is 25°F (-4°C).

Outdoor (1 - 3) High

When the outdoor air temperature rises to or above this
point, the water temperature will be at the Set point 1 at High

Outdoor Temp 1, Set point 2 at High Outdoor Temp 2 and
Set point 3 at High Outdoor Temp 3 parameters (FIG. 1-1).

This parameter can be changed by the installer by accessing
the Outdoor (1-3) High parameter. The temperature range
of this parameter is low outdoor temperature set point to
104°F (40°C). The default value is 70°F (21°C).

Set Point (1 - 3) at Low Outdoor Temperature

When the outdoor air temperature drops to the Outdoor
(1 - 3) Low parameters, the calculated set point will be at

this setting (FIG. 1-1). If the outdoor air temperature drops
further, the set point will continue to increase above this
setting. However, if SH1, SH2, and SH3 are set lower, the
water temperature will be limited by these set points instead.
These parameters can be changed by the installer by accessing
the Set point 1 at Low Outdoor Temp 1, Set point 2 at Low

Outdoor Temp 2 and Set point 3 at Low Outdoor Temp 3
parameters. The temperature range of this parameter is 68°F

(20°C) to 180°F (82°C). The default value is 180°C (82°C).

Set Point (1 - 3) at High Outdoor Temperature

When the outdoor air temperature rises to or above Outdoor
(1 - 3) High parameters, the calculated set point will be at this

setting (FIG. 1-1). These parameters can be changed by the
installer by accessing the Set point 1 at High Outdoor Temp 1,

Set point 2 at High Outdoor Temp 2 and Set point 3 at High
Outdoor Temp 3 parameters. The temperature range of this

parameter is 68°F (20°C) to 190°F (88°C). The default value
is 70°F (21°C).

Outdoor Air Shutdown (SH1 - SH3)

When the outdoor temperature rises above this point, the
control will block all SH demands (DHW demands will still
be active). These parameters can be changed by the installer
by accessing the Outdoor Air Shutdown SH1, SH2, and SH3
parameters. The temperature range of this parameter is 32°F
(0°C) to 104°F (40°C). The default value is 70°F (21°C).

Figure 1-1 Outdoor Air Reset Curve

SET POINT AT

LOW OUTDOOR

TEMPERATURE

(SH)

SET POINT

SET POINT AT

HIGH OUTDOOR

TEMPERATURE

HIGH OUTDOOR

TEMPERATURE

22

LOW OUTDOOR

TEMPERATURE

1 Service (continued)

Service Manual

Outdoor Air Shutdown Differential (SH1 - SH3)

The outdoor air shutdown differential parameter is the
number of degrees below Outdoor Air Shutdown SH1, SH2,
and SH3 parameters the outdoor air temperature must go
before the boiler will respond to a SH demand. These
parameters can be changed by the installer by accessing
the Outdoor Air Shutdown Differential SH1, SH2, and SH3
parameters The temperature range of this parameter is 0°F
(0°C) to 54°F (30°C). The default value is 10°F (6°C).

Shift Reset Curve (SH1 - SH3)

There is a shift reset curve for each outdoor reset. The shift
reset curve parameter shifts the actual set point above or
below the calculated set point by the number of degrees in
this parameter. These parameters can be changed by the
installer by accessing the Shift Reset Curve SH1, SH2, and
SH3 parameters. The temperature range of this parameter
is -17°F (-10°C) to 18°F (10°C). The default value is 0°F
(0°C). This feature will be active if this parameter is set to
anything other than 0°F (0°C).

Boost Temperature

If a SH demand lasts longer than the programmed time
delay setting and there have been no DHW demands, the
control will increase the water temperature set point by the
amount in this parameter. If the SH demand continues
through another time period, the set point will be increased
again. This will continue until either the SH demand ends,
a maximum of 20 increases has occurred, or SH1, SH2,
SH3 maximum set point has been reached. Once the SH
demand has been satisfied the set point will revert back
to its calculated setting. The boost temperature can be
changed by the installer by accessing the Boost Temperature
parameter. The temperature range of this parameter is 0°F
(0°C) to 25°F (14°C). The default value is 0°F (0°C). This
feature will be active if this parameter is set to anything
other than 0°F (0°C).

Anti-Cycling

Anti-Cycling Time

Once a SH demand has been satisfied, a set amount of time must
elapse before the control will respond to a new SH demand. The
control will block the new heat demand and anti-cycling will
be shown in the display until the time has elapsed or the water
temperature drops below the Anti-Cycling Override Differential
parameter. This parameter can be changed by the installer by
accessing the Anti-Cycling Time parameter. The time range for
this parameter is 1 minute to 10 minutes. The default value is
1 minute.

Anti-Cycling Override Differential

The control will bypass the anti-cycling time if the inlet
water temperature drops too much. The control will use the
inlet water temperature the boiler was at when it shut off as
the starting point. If the inlet temperature drops below the
temperature parameter the control will abort anti-cycling and
allow the boiler to fire. This parameter can be changed by
the installer by accessing the Anti-Cycling Override Differential
parameter. The temperature range of this parameter is 0°F (0°C)
to 54°F (30°C). The default value is 10°F (6°C).

Ramp Delay (Enable / Disable)

This parameter allows the installer to enable or disable the SH
ramp delay. The default setting is disabled.

Boost Time

The boost time parameter sets the amount of time that must
elapse with a SH demand before the water temperature
calculated set point will be increased. This parameter can
be changed by the installer by accessing the Boost Time
parameter. The time range for this parameter is 0 minute
to 50 minutes. The default value is 0 minutes.

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Ramp Settings

NOTICE

The SMART SYSTEM control can be programmed to limit
the firing rate for a fixed period of time at the start of a
space heating demand. There are six (6) possible limits,
each with their own time delay. The first limit applies as
soon as the burner starts. Once its time delay expires, the
second limit is applied and its timer begins. The control
steps through these limits until the 6th (sixth) limit expires.
Note, however, that the 6th limit will also limit the rate for
the rest of that heat demand. The installer can adjust the
firing limits and time delays by accessing the Ramp Settings
parameter. Once this parameter is selected, the screen will
show the step number, the time delay for that step and the
limit value corresponding with that step. If the installer
wishes to adjust one of the values in that step, he can press
the NAVIGATION dial until the value he wishes to change
is flashing. The installer can then rotate the NAVIGATION
dial to adjust that value. If the installer presses the RIGHT
SELECT [SAVE] key while the limit value is flashing,
the step value will flash again. The installer can then
select the next step and adjust the delay and limit values
corresponding with that step.

When finished, the installer can press the RIGHT SELECT
[SAVE] key to store the new settings, or the LEFT SELECT
[EXIT] key to return to the Anti-Cycling parameter list
without saving the changes. The delay value can be set
between 0 minutes and 20 minutes. The limit value can be
set between 0% and 100%.

Please note that the brackets ([]) denote
screen status.

Control modes

Controlling Sensor

The SH controlling sensor parameter selects the sensor the
control will use to regulate the boiler firing rate. This parameter
is adjustable by the installer by accessing the Controlling Sensor
parameter. The sensor selections are as follows: The outlet
sensor regulates the firing rate based on the outlet water
temperature of the boiler and the inlet sensor regulates the
firing rate based on the inlet water temperature of the boiler.
If the outlet sensor is selected, and the optional system supply
sensor is connected, the control will regulate the firing rate
based on the system supply sensor temperature. The default
sensor is the Outlet Sensor.

BMS Thermostat Input

When controlling the boiler through the 0 - 10V BMS input or
through ModBus, the boiler can be enabled one of two ways.
With the BMS Thermostat Input parameter set to ACTIVE,
the boiler will be enabled by closing the Heat/Loop Demand 1
input. When set to INACTIVE, the boiler will be enabled by the
voltage level on the 0 - 10V input (in the case of 0 - 10V BMS
control), or the 0 - 10V input value received through ModBus.
The default value is INACTIVE.

BMS

The set point or modulation of the boiler may be controlled
through the 0 - 10V BMS input or through ModBus. When the
BMS parameter is set to INACTIVE, the 0 - 10V input will be
ignored. When set to ACTIVE, the set point or modulation will
be controlled by the voltage on the 0 - 10V input (in the case
of 0 - 10V BMS control), or the 0 - 10V input value received
through ModBus. The default value is INACTIVE.

Figure 1-2 Ramp Delay Interval

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Service Manual

ModBus

When BMS is set to ACTIVE (see BMS Active / Inactive)
and the boiler is being controlled through ModBus, set
ModBus parameter to ACTIVE. Otherwise, set the ModBus
parameter to INACTIVE. Note that the boiler can still
be monitored by ModBus with this parameter set to
INACTIVE. The default value is INACTIVE.

ModBus T/O

The amount of time the unit controls will wait to receive
a communication string from the BMS controller before
reverting back to its own internal parameters. This
parameter is adjustable by the installer by accessing the
ModBus T/O parameter. The adjustment range of this
parameter is 5 seconds to 2 minutes. The default value is
10 seconds.

Cascade Address

The boiler designated as the Leader needs to be programmed
with address 0. All the Member boilers require addresses
from 1 to 7, and the addresses must be different for each
Member. The addresses can be in any order, regardless
of the order in which the units are wired together. This
parameter is adjustable by the installer by accessing the
Cascade Address parameter. The outdoor air (if used) and
system supply sensor must be connected to the Leader
boiler. The default address is 1.

If installing the boilers in an existing system, the new
boilers should be programmed as the Leader and/or the
higher number addresses.

Cascade Type (L/L / EFF)

There are two (2) options for the way a Cascade divides the
load between its heaters. The first is Lead/Lag, designated
as L/L in the menu. This method is used when it is desired
to have the least amount of total flow through the boilers.
This method will modulate the last two (2) boilers. This
provides for smooth transitions when a boiler turns on or
off. When the last boiler reaches 100% and the calculated
load is still increasing, it will start the next boiler at 20%
and reduce the previous boiler to 80%, thus eliminating
the sudden jump in total output of the Cascade. When the
calculated load is decreasing and the last boiler gets down
to 20% fire, it will hold it there and start lowering the firing
rate on the next-to-last boiler. When the next-to-last boiler
reaches 20%, it will turn the last boiler off and raise the
rate of the next-to-last boiler to 40%, thus eliminating the
sudden drop in total output of the Cascade.

As the calculated load increases further and both boilers ramp
up to 90%, it lowers the rate of the first two (2) boilers to 60%

and brings the next boiler on at 60%. The three (3) boilers

then modulate together. As the calculated load decreases, the
boilers will reach a lower threshold (default = 30%), at which
time the last boiler (the third in our example) will turn off and
the Cascade will increase the rates of the remaining boilers to
provide the equivalent total output as before ((3 x 30%) / 2 =
45% in our example).

Maximum Cascade Set Point

This parameter determines the set point used by the individual
boilers in a Cascade. When a boiler is commanded to fire by
the Leader boiler, it will attempt to achieve this temperature at
its outlet. The Leader boiler will limit the modulation of the
last boiler to fire in order to hold the temperature at the system
supply sensor to the user set point. If any of the boiler outlet
temperatures reach the maximum cascade set point, the boiler
will then modulate down on its own in order to keep its outlet
temperature within the maximum cascade set point. Therefore,
this parameter can be used to limit the outlet temperatures of
all the boilers in a Cascade. Note that this parameter does
not apply when the boiler is heating an indirect DHW tank.
This parameter is adjustable by the installer by accessing the
Maximum Cascade Set Point parameter. The temperature
range of this parameter is 32° (0°C) to 190°F (88°C). The
default maximum cascade set point is 185°F (85°C).

Cascade Offset

This parameter determines how much the temperature must
go above set point before the lead boiler will turn off. This
parameter can be adjusted by the installer by accessing the
Cascade Offset parameter. The temperature range of this
parameter is 0° to 20°F (11°C) The default value is 10°F (6°C).

Cascade Differential

This parameter determines how much the temperature must
go below the turn off temperature (Set point + Offset) before
the lead boiler turns on. This parameter can be adjusted by the
installer by accessing the Cascade Differential parameter. The
temperature range of this parameter is 0°F to 60°F (33°C) The

default value is 20°F (11°C).

Minimum On/Off Time

In order to prevent units in a Cascade from short cycling,
this parameter defines the minimum ON and OFF time for
each unit. The installer can adjust this time by accessing the
Minimum On/Off Time parameter. The minimum setting is 0
seconds and the maximum setting is 10 minutes. The default
is 30 seconds.

The other Cascade divider method is Efficiency
Optimization, designated as EFF in the menu. This
method is used, as the name implies, when it is desired
to have the most efficient system. When the first boiler
reaches a certain rate (default = 90%), it lowers its rate
to 45% and turns on the next boiler at 45%. The two (2)
boilers then modulate at the same rate.

Minimum Next On Time

In order to reduce the risk of temperature overshoot with
a Cascade, this parameter defines the minimum time delay
from starting one unit until the next unit may be started. The
installer can adjust this time delay by accessing the Minimum
Next On Time parameter. The minimum setting is 0 minutes
and the maximum setting is 10 minutes. The default is 60
seconds.

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Circulation pumps

System Pump Delay

The system pump delay parameter sets the length of time the
system pump (if connected) will run after a SH demand has
been satisfied. This parameter is adjustable by the installer by
accessing the System Pump Delay parameter. The time range
for this parameter is 1 second to 40 minutes. The default time
is 30 seconds.

Boiler Pump Delay

The SH pump delay parameter sets the length of time the
boiler pump will run after a SH demand has been satisfied.
Setting the delay time to 0 will disable the pump. This
parameter is adjustable by the installer by accessing the Boiler
Pump Delay parameter. The time range for this parameter is
1 second to 40 minutes. The default time is 30 seconds.

DHW Pump Delay

The DHW pump delay parameter sets the length of time the
DHW pump (if connected) will run after a DHW demand has
been satisfied. This parameter is adjustable by the installer by
accessing the DHW Pump Delay parameter. The time range
for this parameter is 10 seconds to 40 minutes. The default
time is 1 minute.

Boiler Pump Anti-Seize Delay

If the boiler pump does not run for 24 hours, it will be
turned on briefly to prevent it from seizing. The length of
time it runs is determined by the Boiler Pump Anti-Seize
Delay parameter. The range of this setting is 0 seconds to 50
minutes. The default setting is 20 seconds.

DHW Pump Anti-Seize Delay

If the boiler pump does not run for 24 hours, it will be turned
on briefly to prevent it from seizing. The length of time it runs
is determined by the DHW Pump Anti-Seize Delay parameter.
The range of this setting is 0 seconds to 50 minutes. The default
setting is 20 seconds.

System Pump Anti-Seize Delay

If the boiler pump does not run for 24 hours, it will be turned
on briefly to prevent it from seizing. The length of time it runs
is determined by the System Pump Anti-Seize Delay parameter.
The range of this setting is 0 seconds to 50 minutes. The default
setting is 20 seconds.

BMS

BMS Type

When programmed for BMS control through the 0 - 10V BMS
input or through ModBus, the 0 - 10V signal can be interpreted
as either a modulation command or a set point. When the BMS
Type parameter is set to POWER, the 0 - 10V signal will control
the modulation. When set to SETPOINT, the 0 - 10V signal
will control the SH set point. The default setting is SETPOINT.

Volts at Minimum

When programmed for BMS control through the 0 - 10V BMS
input or through ModBus, the Volts at Minimum parameter
should be set to the minimum voltage signal sent to the
SMART SYSTEM control. The range of this parameter is 0.0V
to the Volts at Maximum value. The default setting is 2.0V.

Boiler Pump Minimum Voltage

The speed of the boiler pump can be controlled by the
SMART SYSTEM control in order to maintain a minimum
T through the heat exchanger. Thus, as the firing rate
decreases, the speed of the boiler pump can decrease as well.
The SMART SYSTEM control outputs a 0 - 10V signal to the
boiler pump to control its speed. The Boiler Pump Minimum
Voltage parameter determines the minimum voltage given to
the boiler pump, thereby setting its minimum speed. The
range of this setting is 2.5V to 10V. The default setting is

3.5V.

System Pump Type

The system pump can be programmed to operate in response
to any of the Room Thermostat inputs, or to run continuously
until the boiler goes into Outdoor Shutdown. To program
the system pump to operate only with a space heating call
for heat, set the System Pump Type parameter to CFH. To
program the system pump to run continuously until outdoor
shutdown starts, set the System Pump Type parameter to
WWSD. The default setting is CFH.

26

Volts at Maximum

When programmed for BMS control through the 0 - 10V BMS
input or through ModBus, the Volts at Maximum parameter
should be set to the maximum voltage signal sent to the
SMART SYSTEM control. The range of this parameter is the
Volts at Minimum value to 10.0V. The default value is 10.0V.

Rate at Minimum Volts

When programmed for BMS control through the 0 - 10V BMS
input or through ModBus and the BMS Type is programmed as
POWER, the modulation percentage represented by the Volts
at Minimum parameter is set by the Rate at Minimum Volts
parameter. The minimum value is 0% and the maximum is
the Rate at Maximum Volts setting. The default value is 20%.

Rate at Maximum Volts

When programmed for BMS control through the 0 - 10V BMS
input or through ModBus and the BMS Type is programmed as
POWER, the modulation percentage represented by the Volts
at Maximum parameter is set by the Rate at Maximum Volts
parameter. The minimum value is the Rate at Minimum Volts
setting and the maximum is 100%. The default value is 100%.

1 Service (continued)

Service Manual

Set Point at Minimum Volts

When programmed for BMS control through the 0 - 10V BMS
input or through ModBus and the BMS Type is programmed as
SETPOINT, the set point represented by the Volts at Minimum
parameter is set by the Set Point at Maximum Volts parameter.
The minimum value is 32°F (0°C) and the maximum is the
Set Point at Maximum Volts setting. The default value is 70°F
(21°C).

Set Point at Maximum Volts

When programmed for BMS control through the 0 - 10V BMS
input or through ModBus and the BMS Type is programmed as
SETPOINT, the set point represented by the Volts at Maximum
parameter is set by the Set Point at Maximum Volts parameter.
The minimum value is the Set Point at Minimum Volts setting
and the maximum is 190°F (88°C). The default value is 180°F
(82°C).

On Volts

When programmed for BMS control through the 0 - 10V BMS
input or through ModBus and the BMS Thermostat Input is set
to INACTIVE, the On Volts parameter determines the 0 - 10V
BMS input voltage at which the boiler is enabled. The minimum
value is 0.5V and the maximum is 10.0V. The default value is

2.0V.

Off Differential Volts

When programmed for BMS control through the 0 - 10V BMS
input or through ModBus and the BMS Thermostat Input is set
to INACTIVE, the Off Differential Volts parameter determines
how far below the On Volts setting the 0 - 10V BMS input
voltage must be in order to disable the boiler. The minimum
value is 0.2V and the maximum is the On Volts setting. The
default value is 1.0V.

Service Notification Cycles

When the boiler control determines that a scheduled
service is due based on the number of boiler cycles, the
boiler display will alternate the standard boiler display
text with the message SERVICE DUE every 5 seconds.
This parameter is adjustable by the installer by accessing
the Service Notification Cycles parameter. The range for
this parameter is 0 cycles to 100,000 cycles. The default is
50,000 cycles.

Reset Maintenance Reminder

Once servicing has been completed, the service notification
counter should be reset. This parameter can be reset by
the installer by accessing the Reset Maintenance Reminder
parameter. Once accessed, press the RESET key to reset the
service notification counter.

Service Name and Phone Number

NOTICE

When a Maintenance Reminder timer or counter has
expired, a Maintenance Reminder screen will appear on the
display. By programming the installer’s name and phone
number, this information will appear on the Maintenance
Reminder Screen at that time. This can be programmed by
accessing the Service Name and Phone Number parameter.
When selected, another menu will appear with PHONE
and NAME.

1. Rotate the NAVIGATION dial to point to the
name/phone number to program and press the
NAVIGATION dial. The screen will now display the
selected item (either PHONE or NAME).

2. Press the NAVIGATION dial again. A cursor will
appear at the bottom of the screen. By rotating the
NAVIGATION dial, various numbers and characters
will appear. When the desired number/character is
found, press the NAVIGATION dial. The cursor will
move to the next position.

3. Repeat this procedure until the entire message is
entered. If you make a mistake and wish to back up
one character, rotate the NAVIGATION dial until
the back arrow () character is displayed and press the
NAVIGATION dial.

4. When finished, press the RIGHT SELECT [SAVE] key
to return to the previous menu.

Please note that the brackets ([]) denote
screen status.

27

2 Maintenance

Maintenance and annual startup

Table 2-1 Service and Maintenance Schedules

Service Manual

Service technician

(see the following pages for instructions)

General:

• Address reported problems

• Inspect interior; clean and vacuum if
necessary;

• Clean condensate trap and fill with fresh
water

• Check for leaks (water, gas, flue,
condensate)

• Verify flue and air lines in good condition
and sealed tight

• Check system water pressure/system
piping/expansion tank

• Check control settings

• Check ignition and flame sense
electrodes (sand off any deposits; clean
and reposition)

ANNUAL START-UP

• Check wiring and connections

• Perform start-up checkout and
performance verification per Section 10
in the Knight Wall Mount Installation and
Operation Manual.

• Flame inspection (stable, uniform)

Owner maintenance

(see the Knight Wall Mount User’s Information

Manual for instructions)

• Check boiler area

Daily

Monthly

Periodically

• Check pressure/temperature
gauge

• Check vent piping

• Check air piping

• Check air and vent termination
screens

• Check relief valve

• Check condensate drain system

• Check air vents

• Test low water cutoff (if used)

• Reset button (low water cutoff)

• Flame signal (at least 10 microamps at
high fire)

• Clean the heat exchanger if flue
temperature is more than 54°F above
return water temperature.

If combustion or performance
indicate need:

• Clean heat exchanger

• Remove and clean burner using
compressed air only

• Clean the blower wheel

28

Every

6 months

End

of season

months

• Check boiler piping (gas and
water) for leaks

• Operate relief valve

• Shut boiler down (unless boiler
used for domestic hot water)

2 Maintenance (continued)

Service Manual

 WARNING

 WARNING

 WARNING

Follow the Service and maintenance procedures given throughout this manual and in component literature
shipped with the boiler. Failure to perform the service and maintenance could result in damage to the boiler or
system. Failure to follow the directions in this manual and component literature could result in severe personal
injury, death, or substantial property damage.

The boiler should be inspected annually only by a qualified service technician. In addition, the maintenance
and care of the boiler designated in Table 2-1 and explained on the following pages must be performed to assure
maximum boiler efficiency and reliability. Failure to service and maintain the boiler and system could result in
equipment failure.

Electrical shock hazard – Turn off power to the boiler before any service operation on the boiler except as noted
otherwise in this instruction manual. Failure to turn off electrical power could result in electrical shock, causing
severe personal injury or death.

Address reported problems

1. Inspect any problems reported by the owner and correct
before proceeding.

Inspect boiler area

1. Verify that boiler area is free of any combustible materials,
gasoline and other flammable vapors and liquids.

2. Verify that air intake area is free of any of the contaminants
listed in Section 1 of the Knight Wall Mount Installation
and Operation Manual. If any of these are present in the
boiler intake air vicinity, they must be removed. If they
cannot be removed, reinstall the air and vent lines per
this manual and the Knight Wall Mount Installation and
Operation Manual.

Figure 2-1 Condensate Trap

Inspect boiler interior

1. Remove the front access cover and inspect the interior of
the boiler.

2. Vacuum any sediment from inside the boiler and
components. Remove any obstructions.

Clean condensate trap

1. Remove the clean out cap on the bottom of the trap. Let the
condensate and any debris drain out.

2. Fill with fresh water until the water begins to pour out of the
drain.

3. Replace the clean out cap and resume operation.

 WARNING

The condensate trap must be filled with
water during all times of boiler operation to
avoid flue gas emission from the condensate
drain line. Failure to fill the trap could result
in severe personal injury or death.

Check all piping for leaks

 WARNING

1. Inspect all water and gas piping and verify to be leak free.

2. Look for signs of leaking lines and correct any problems
found.

3. Check gas line using the procedure found in Section 7 - Gas
Connections of the Knight Wall Mount Installation and
Operation Manual.

Eliminate all system or boiler leaks.
Continual fresh makeup water will reduce
boiler life. Minerals can build up in sections,
reducing heat transfer, overheating heat
exchanger, and causing heat exchanger
failure. Leaking water may also cause severe
property damage.

29

2 Maintenance

Service Manual

Flue vent system and air piping

1. Visually inspect the entire flue gas venting system and air
piping for blockage, deterioration or leakage. Repair any
joints that show signs of leakage. Verify that air inlet pipe
is connected and properly sealed.

2. Verify that boiler vent discharge and air intake are clean
and free of obstructions.

 WARNING

Failure to inspect for the above conditions
and have them repaired can result in
severe personal injury or death.

Check water system

1. Verify all system components are correctly installed and

operational.

2. Check the cold fill pressure for the system. Verify it is

correct (must be a minimum of 12 psi).

3. Watch the system pressure as the boiler heats up (during

testing) to ensure pressure does not rise too high.
Excessive pressure rise indicates expansion tank sizing or
performance problem.

4. Inspect automatic air vents and air separators. Remove

air vent caps and briefly press push valve to flush vent.
Replace caps. Make sure vents do not leak. Replace any
leaking vents.

Check expansion tank

1. Expansion tanks provide space for water to move in

and out as the heating system water expands due to
temperature increase or contracts as the water cools.
Tanks may be open, closed or diaphragm or bladder
type. See Section 6 - Hydronic Piping of the Knight Wall
Mount Installation and Operation Manual for suggested
best location of expansion tanks and air eliminators.

Check boiler relief valve

1. Inspect the relief valve and lift the lever to verify flow.

Before operating any relief valve, ensure that it is piped
with its discharge in a safe area to avoid severe scald
potential. Read Section 6 - Hydronic Piping of the
Knight Wall Mount Installation and Operation Manual
before proceeding further.

 WARNING

 WARNING

2. After following the above warning directions, if the relief
valve weeps or will not seat properly, replace the relief
valve. Ensure that the reason for relief valve weeping is
the valve and not over-pressurization of the system due
to expansion tank waterlogging or undersizing.

Safety relief valves should be re-inspected
AT LEAST ONCE EVERY THREE YEARS,
by a licensed plumbing contractor or
authorized inspection agency, to ensure
that the product has not been affected by
corrosive water conditions and to ensure
that the valve and discharge line have not
been altered or tampered with illegally.
Certain naturally occurring conditions
may corrode the valve or its components
over time, rendering the valve inoperative.
Such conditions are not detectable unless
the valve and its components are physically
removed and inspected. This inspection
must only be conducted by a plumbing
contractor or authorized inspection
agency – not by the owner. Failure to
re-inspect the boiler relief valve as directed
could result in unsafe pressure buildup,
which can result in severe personal injury,
death, or substantial property damage.

Following installation, the valve lever
must be operated AT LEAST ONCE
A YEAR to ensure that waterways are
clear. Certain naturally occurring
mineral deposits may adhere to the valve,
rendering it inoperative. When manually
operating the lever, water will discharge
and precautions must be taken to avoid
contact with hot water and to avoid water
damage. Before operating lever, check
to see that a discharge line is connected
to this valve directing the flow of hot
water from the valve to a proper place of
disposal. Otherwise severe personal injury
may result. If no water flows, valve is
inoperative. Shut down the boiler until a
new relief valve has been installed.

30

2 Maintenance (continued)

Service Manual

Inspect ignition and flame sense
electrodes

1. Remove the ignition and flame sense electrodes from the
boiler heat exchanger access cover.

2. Remove any deposits accumulated on the ignition/flame
sense electrode using sandpaper. If the electrodes cannot
be cleaned satisfactorily, replace with new ones.

3. Replace ignition/flame sense electrode, making sure
gasket is in good condition and correctly positioned.

Check ignition ground wiring

1. Inspect boiler ground wire from the heat exchanger
access cover to ground terminal strip.

2. Verify all wiring is in good condition and securely
attached.

3. Check ground continuity of wiring using continuity
meter.

Check burner flame

1. Inspect flame through observation window.

2. If the flame is unsatisfactory at either high fire or low fire,
turn off boiler and allow boiler to cool down. Remove
the burner and clean it thoroughly using a vacuum
cleaner or compressed air. Do not use compressed air to
clean burner if performed inside a building.

3. Remove the burner, reference FIG. 2-2 below.

4. When replacing the burner, ensure gasket is in good
condition and positioned correctly (FIG. 2-2).

Figure 2-2 Burner Assembly

4. Replace ground wires if ground continuity is not
satisfactory.

Check all boiler wiring

1. Inspect all boiler wiring, making sure wires are in good
condition and securely attached.

Check control settings

1. Set the SMART SYSTEM control module display to
Parameter Mode and check all settings. See Section 1 of
this manual. Adjust settings if necessary. See Section 1 of
this manual for adjustment procedures.

2. Check settings of external limit controls (if any) and
adjust if necessary.

Perform start-up and checks

1. Start boiler and perform checks and tests specified

in Section 10 - Start-up of the Knight Wall Mount
Installation and Operation Manual.

Check flame signal

1. At high fire the flame signal shown on the display should
be at least 10 microamps.

2. A lower flame signal may indicate a fouled or damaged
flame sense electrode. If cleaning the flame sense
electrode does not improve, ground wiring is in good
condition, and ground continuity is satisfactory, replace
the flame sense electrode.

3. See Section 3 - Troubleshooting in this manual for other
procedures to deal with low flame signal.

2. Verify cold fill pressure is correct and that operating
pressure does not go too high.

31

2 Maintenance

Service Manual

Review with owner

1. Review the Knight Wall Mount User’s Information Manual

with the owner.

2. Emphasize the need to perform the maintenance schedule

specified in the Knight Wall Mount User’s Information
Manual (and in this manual as well).

3. Remind the owner of the need to call a licensed contractor

should the boiler or system exhibit any unusual behavior.

4. Remind the owner to follow the proper shutdown procedure

and to schedule an annual start-up at the beginning of the
next heating season.

Cleaning boiler heat exchanger

For recommended materials; including brush, appropriate
extension(s), refractory cover, and detailed instructions see
Table 2B - Heat Exchanger Cleaning Kits.

1. Shut down boiler:

• Follow the “To Turn Off Gas to Appliance”
instructions for the boiler in Section 10 - Startup of
the Installation and Operation Manual.

• Do not drain the boiler unless it will be exposed to
freezing temperatures. If using freeze prevention
fluid in system, do not drain.

2. Allow time for the boiler to cool to room temperature if it

has been firing.

3. Remove the nuts securing the heat exchanger access cover

to the heat exchanger and set aside.

4. Remove the heat exchanger access cover, burner, and

gas/air arm assembly.

11. Close isolation valves on piping to isolate boiler from
system. Attach a hose to the boiler drain and flush boiler
thoroughly with clean water by using purging valves to
allow water to flow through the water make-up line to the
boiler.

12. Perform start-up and check-out procedures in the Check
Flame and Combustion - Section 10 - Startup of the
Installation and Operation Manual.

13. Replace the access cover and restore boiler to operation.

Table 2B Heat Exchanger Cleaning Kits

Model

51 - 106 KIT30062

151 - 211 KIT30063

 CAUTION

Figure 2-3 Rope Gasket - Heat Exchanger Door

Kit

Number

* Do NOT use a metal brush. Only use
the kit provided brush or an equivalent
replacement nylon brush.

Part

Number

CTN20005 Rear Refractory Cover

MSC20083* Nylon 4” Wheel Brush*

MSC20085 1/4” x 12” Drill Extension

CTN20005 Rear Refractory Cover

MSC20083* Nylon 4” Wheel Brush*

MSC20084 3mm Allen Wrench
MSC20086 1/4” x 24” Drill Extension

Component
Description

ROPE GASKET

 WARNING

5. Remove the condensate hose from the heat exchanger end.
Connect a field supplied 3/4” diameter hose to a drain pan.
Using field supplied means, cover the refractory in the back
of the combustion chamber of the heat exchanger.

6. Use a vacuum cleaner to remove any accumulation on the
boiler heating surfaces. Do not use any solvent.

7. Brush the heat exchanger while dry using a nylon bristle
brush. Caution: DO NOT use a metal brush. Re-vacuum
the heat exchanger.

8. Finish cleaning using a clean cloth dampened with warm
water. Rinse out debris with a low pressure water supply.

9. Allow the heat exchanger to thoroughly dry.

10. Remove the field supplied rear refractory cover from the
back of the combustion chamber of the heat exchanger and
reassemble.

The boiler contains ceramic fiber materials.
Use care when handling these materials per
instructions in the Service Manual. Failure
to comply could result in severe personal
injury.

32

CAUTION: IF GASKET IS DAMAGED

DO NOT REUSE, THE HEAT EXCHANGER DOOR

MUST BE REPLACED.

NOTICE

Rope gasket is intended for sealing combustion
(FIG. 2-3). If damaged DO NOT reuse, the
heat exchanger door must be replaced. Consult
factory for replacement heat exchanger door
(kit WTR30002).

Oiled bearing circulators

1. The circulator shipped with the Knight wall mount boiler
is water-lubricated. No oiling is required.

2. Check other circulators in the system. Oil any circulators
requiring oil, following circulator manufacturer’s
instructions. Over-oiling will damage the circulator.

3. Replace the boiler front access cover.

3 Troubleshooting

Service Manual

 WARNING

 WARNING

Label all wires prior to disconnection
when servicing controls. Wiring
errors can cause improper and
dangerous operation. Always
disconnect power to the boiler before
servicing. Failure to comply could
result in severe personal injury, death,
or substantial property damage.

Never jumper (bypass) any device
except for momentary testing as
outlined in the Troubleshooting
chart. Severe personal injury, death,
or substantial property damage can
result.

Before troubleshooting:

1. Have the following items:
a. Voltmeter that can check 120 vac, 24 vac, and
12 vdc.
b. Continuity checker.
c. Contact thermometer.

2. Check for 120 vac (minimum 102 vac to maximum

132 vac) to boiler.

3. Make sure thermostat is calling for heat and contacts

(including appropriate zone controls) are closed.
Check for 24 vac between thermostat wire nuts and
ground.

4. Make sure all external limit controls are installed

and operating.

Check the following:

Check control module fuses

NOTICE

1. Turn OFF the power to the boiler at the external line
switch.

2. Remove top access cover.

3. Remove the control module cover.

4. Inspect fuses F1, F2, and F3, see FIG 3-1 below.

Figure 3-1 Control Module Fuses

F3 - .80 AMP FUSE

24V DC POWER SUPPLY

F1 - 5 AMP FUSE

PUMPS

F2 - 3.15 AMP FUSE

BLOWER

5. The boiler is shipped with three (3) spare fuses in a plastic bag
provided with the unit.

6. If necessary, replace open fuse (F3 is .80 amps, F2 is 3.15 amps,
and F1 is 5 amps).

Note: Fuses F1, F2 and F3are all slow blow fuses.

ALWAYS check control module fuses
before replacing control module or any
major components (blower, etc.). If one
of these fuses is blown, it can prevent the
control module or other components from
operating.

1. Wire connectors to control module are securely
plugged in at the module and originating control.

2. Gas pressures:

• Maximum: 14 inches w.c. (natural and LP) with
no flow (lockup) or with boiler on

• Minimum: 4 inches w.c. (natural), 8 inches w.c.
(LP) with gas flowing (verify during boiler
startup)

 WARNING

7. Install control module cover and top access cover after fuse
inspection.

8. Restore power to the boiler at the external line switch and verify
boiler operation (Section 10 - Start-up in the Knight Wall
Mount Installation and Operation Manual) after completing
boiler service.

Do not jumper fuse or replace with any fuse
except as specified. Failure to comply could
result in severe personal injury, death, or
substantial property damage.

33

Service Manual

3 Troubleshooting

Table 3-1 Troubleshooting Chart - No Display

FAULT CAUSE CORRECTIVE ACTION

- No 120 vac supplied to unit. • Check external line switch, fuse, or breaker.

• Check position of ON/OFF switch. Turn switch to the
ON position.

• Check 120 vac through the ON/OFF switch.

• Check wiring harness connection between display
board and main control board. Connect
harness at both points.

No Display

- No voltage through the switch. • Replace switch.

- Bad display board. • Replace board.

No Burner

Operation

- Bad main control board. • Replace the main control board.

- Blown fuse. • Replace fuse F3 on the main control board, see
page 33 of this manual.

- Main control board temperature set point

satisfied.

- Remote thermostat satisfied. • Review remote thermostat setting.

- Outside air temperature above Warm

Weather Shutdown (WWSD) set point for
main control board.

- Unit locked out on fault. • Consult display for specific fault. Refer to fault

- Ramp delay active. • Check ramp delay parameter settings. Optional PC

• Review temperature setting.

• Check location of outside air sensor. Check
resistance of outdoor air sensor and compare to Table
3-2B on page 35 of this manual.

descriptions on page 37 of this manual for corrective
actions.

software required.

• Turn ramp delay feature off. See page 23 of this
manual for instructions on how to turn this feature off.

Unit Does

Not Modulate

Above 50%

34

- Boiler controlled by BMS.

- Flue sensor open.

• Check BMS parameter settings. Optional PC
software required.

• Verify that the flue sensor is located in the flue outlet.

• Check wiring connections at the flue sensor.

• Check the resistance of the flue sensor and compare
to Table 3-2D on page 35 of this manual.

Service Manual

3 Troubleshooting (continued)

Checking temperature sensors

The boiler temperature sensors (inlet water, outlet water, system water, flue, and outdoor air) are all resistance type devices. The
following tables show the correct values for the sensors at various temperatures. Use an ohmmeter to read the resistance of the
sensor at a known temperature. If the resistance of the sensor does not closely match its corresponding table, replace the sensor

It is important to note that the flue and outlet water sensors have two temperature sensing devices in one housing. These devices
are designated as S1a/S1b, outlet sensor and S3a/S3b, flue sensor. Please reference the wiring diagram in the Knight Wall Mount
Installation and Operation Manual for correct terminal location.

Table 3-2A - Inlet Water/System Sensor Resistance vs.
Temperature

Temperature Resistance Temperature Resistance

50 18,780 158 1,990

68 12,263 176 1,458

86 8,194 194 1,084

104 5,592 212 817

122 3,893

140 2,760

Table 3-2C - Outlet Water Sensor Resistance vs. Temperature

S1a

(Wire Color - R/BK and Y)

Temperature Resistance Temperature Resistance Temperature Resistance Temperature Resistance

50 19,553 158 2,004 50 40,030 158 3,478

68 12,690 176 1,464 68 25,030 176 2,492

86 8,406 194 1,084 86 16,090 194 1,816
104 5,715 212 816 104 10,610 212 1,344
122 3,958 122 7,166
140 2,786 140 4,943

Table 3-2B - Outdoor Air Sensor Resistance vs.
Temperature

Temperature Resistance Temperature Resistance

-50 490,813 20 46,218

-40 336,606 30 34,558

-30 234,196 40 26,099

-20 165,180 50 19,900
10 118,018 60 15,311

0 85,362 70 11,883

10 62,465 80 9,299

S1b

(Wire Color - G and Y)

Table 3-2D - Flue Sensor Resistance vs. Temperature

S3a

(Wire Color - W/B and Y)

Temperature Resistance Temperature Resistance Temperature Resistance Temperature Resistance

50 40,030 158 3,478 50 258,500 158 16,870

68 25,030 176 2,492 68 125,500 176 12,000

86 16,090 194 1,816 86 80,220 194 8,674
104 10,610 212 1,344 104 52,590 212 6,369
122 7,166 122 35,270
140 4,943 140 24,160

(Wire Color - PR and Y)

S3b

35

Service Manual

3 Troubleshooting

Table 3-3 Troubleshooting Chart - Noisy System

FAULT CAUSE CORRECTIVE ACTION

Noisy

Operation

- Supply gas problem. Natural gas
pressures should be between 4 inches w.c.
and 14 inches w.c. LP gas pressures
should be between 8 inches w.c. and
14 inches w.c.

- Gas/air mixture problem. • Refer to the Gas Valve Adjustment Procedure on

- Dirty/damaged burner. • Refer to page 31 in this manual for the burner removal

- Low water flow through the heat exchanger. • Refer to Section 6 - Hydronic Piping of the Knight Wall

- Air in the piping system. • Properly purge all air from the piping system.

• Refer to Section 7 - Gas Connections of the Knight Wall
Mount Boiler Installation and Operation Manual for
detailed information concerning the gas supply.

page 47 of this manual for the proper gas valve setting.
Verify that the vent/air intake lengths do not exceed the
maximum listed in the General Venting section of the
Knight Wall Mount Installation and Operation Manual.

and inspection procedure. Clean or replace the burner
as necessary.

Mount Boiler Installation and Operation Manual for
minimum flow rates. Verify that the boiler is piped in a
primary/secondary fashion and that the boiler and
system pump are running on a call for heat.

No Pump

Operation -

Boiler Pump

System Pump

or

DHW Pump

Relief Valve

Opening

- Low system water pressure. • Verify system pressure is a minimum of 12 psi.

- Blown fuse.

- Faulty pump.

- Internal fault on control board.

- System pressure exceeds relief valve
setting.

• Replace fuse F1 on the control board, see page 33 of
this manual.

Note: Make sure pump amperage does not exceed

1.8 amps.

• Replace pump.

• Replace main control board.

• Lower the system pressure below the 30 psi rating of
the supplied relief valve or replace the standard relief
valve with a higher rated valve up to the maximum
pressure of the heat exchanger.

• Improperly sized expansion tank.

36

Service Manual

3 Troubleshooting (continued)

Table 3-4 Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

• Reset the pressure switches.

• Measure the supply gas pressure to determine cause
of failure. Natural gas pressures should be between
4 - 14 inches w.c. and LP gas pressures
should be between 8 - 14 inches w.c.

• Refer to Section 7 - Gas Connections of the Knight
Wall Mount Boiler Installation and Operation Manual
for detailed information concerning the gas supply.

• Correct the supply gas pressure if necessary.

• Check for a loose or misplaced jumper if pressure
switches are not installed.

• Check for a loose or misplaced jumper on the Low
Voltage Connection Board.

• Check for the addition of a device wired across the
gas pressure switch terminals on the Low Voltage
Connection Board.

Gas Pressure SW

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the
SMART SYSTEM

to reset.)

display

Either the optional manual reset low gas
pressure switch or the optional manual reset
high gas pressure switch tripped.

- The gas pressure switch contacts on the
Low Voltage Connection Board are open.

Flow Switch/

LWCO

(will require a manual

reset once condition has

been corrected. Press
the RESET button on the
SMART SYSTEM display

to reset.)

Blocked Drain SW

(will require a manual

reset once condition has

been corrected. Press
the RESET button on the
SMART SYSTEM display

to reset.)

APS

Open

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the
SMART SYSTEM

to reset.)

display

Either the optional flow switch or the optional
low water cutoff is not making.

Blown fuse.

The blocked drain switch has detected
excessive condensate build up inside the
unit.

Air pressure switch contacts are open.

• Check boiler pump operation on a call for heat.

• Check for closed valves or obstructions in the boiler
piping.

• Verify system is full of water and all air has been
purged from the system.

• Check for loose or misplaced jumpers if flow switch or
LWCO is not installed.

• Replace fuse F3 on the control board, see page 33
of this manual.

• Check condensate tube from unit to floor drain for
proper installation and obstructions.

• Inspect condensate trap for blockage. Clean if
necessary.

• Check for loose wiring connection at wire harness
plug.

• Bad blocked drain switch. Replace switch.

• Check the wiring connections to switch. Wires should
be connected to the common and normally closed
terminals.

• Air intake lengths exceed the maximum allowed
lengths. Refer to Section 3 - General Venting of the
Knight Wall Mount Installation and Operation Manual
for proper lengths.

• Check for obstruction or blockage in the air
intake pipes or at terminations.

• Check reference hoses connected to the air pressure
switch for blockage or obstruction.

• Inspect the burner. Reference page 31 of this manual
for removal and cleaning procedures. Replace if
necessary.

• Inspect the heat exchanger. Reference page 32 of
this manual for removal and cleaning procedures.
Replace if necessary.

• Faulty air pressure switch. Replace switch.

37

Service Manual

3 Troubleshooting

Table 3-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

Anti-cycling

Flame Fail Ign

(will require a manual

reset once the condition

has been corrected.

Press the RESET button

on the SMART SYSTEM

display to reset.)

The main control board has received a call
for heat too quickly after the previous call for
heat has ended.

The unit has failed to prove main burner
ignition after four (4) attempts.

• The control board will release the call for heat after a
set time period.

• The control board will release the call for heat if the
outlet temperature drops too quickly.

• Inspect spark electrode and associated wiring for
damage and connection. Reference page 31 of this
manual for removal and cleaning procedures.
Replace if necessary.

• Check for proper electrical grounding of the unit.

• Check incoming supply gas pressure. Natural gas
pressures should be between 4 - 14 inches w.c. and
LP gas pressures should be between 8 - 14 inches w.c.
Refer to Section 7 - Gas Connections of the Knight
Wall Mount Boiler Installation and Operation Manual
for detailed information concerning the gas supply.

• Verify that the plastic hose from the gas valve to the air
inlet is connected and is not damaged.

• Verify that the vent/air intake pipes are correctly
installed and that there are no obstructions.

• Check for 24 vac to the gas valve at the 2-pin
connection on the side of the main control board during
the ignition attempt. If no voltage is present, replace
the main control board.

• If 24 vac is present at the main control board, check
the wiring between the main control board and the gas
valve. Replace the wiring if necessary. Do not
disconnect the wiring from the gas valve and attempt to
measure voltage at that point. The main control board
can detect if the gas valve is not connected and will
display the Gas Valve or Gas Valve Fail fault.

• If 24 vac is present, check the outlet of the valve to
ensure the valve is flowing gas. With a manometer
connected to the outlet tap of the gas valve, when the
unit is in the prepurge period, there should be a
negative pressure present. When the valve is
energized a change in pressure should occur. If the
pressure change does not occur, the gas valve is not
opening. Replace the gas valve.

• Inspect flame sensor and associated wiring.
Reference page 31 of this manual for removal and
cleaning procedures. Replace if necessary.

• Inspect and clean the heat exchanger as necessary.
Reference page 32 of this manual for cleaning
procedures.

• Inspect the burner. Reference page 31 of this manual
for removal and cleaning procedures. Replace if
necessary.

• Replace the main control board.

38

Service Manual

3 Troubleshooting (continued)

Table 3-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

Flame

Sequence

(will require a manual

reset once the condition

has been corrected.

Press the RESET

button on the SMART

SYSTEM

display to

reset.)

Outlet ARHL

The flame detector circuit is seeing a flame
signal while no flame is present.

The outlet water temperature has exceeded
the setting of the automatic reset high limit.

• Check supply voltage for proper polarity.

• Check external wiring for voltage feedback.

• Check the flame rod and make sure it is clean.

• Check the internal wiring for bad connections.

• Replace main control board.

• Adjust the set point of the auto reset limit to a higher
setting up to a maximum of 200°F. Reference the
Knight Wall Mount Installation and Operation Manual
for adjusting procedures.

• Verify that the system is full of water and that all air
has been properly purged from the system.

• Verify that the boiler is piped properly into the heating
system. Refer to Section 6 - Hydronic Piping of the
Knight Wall Mount Installation and Operation Manual
for the proper piping methods for the wall mount boiler.

• Check 120 vac to boiler pump motor on a call for
heat. If voltage is not present, check wiring back to
the main control board.

• Replace the main control board if necessary.

• If 120 vac is present on a call for heat and the boiler
pump is not operating, replace the pump.

• If the system pump is a variable speed pump, ensure
that the system flow is not less than the boiler flow.

• If operating on something other than an outlet sensor,
check temperature setting of the main control board.

• If the optional manual reset high limit has tripped,
check setting of the device.

• Check resistance of water sensors and compare to
Table 3-2A on page 35 of this manual. Replace
sensor if necessary.

• Replace high limit.

Outlet MRHL

(will require a manual

reset once the condition

has been corrected.

Press the RESET

button on the SMART

SYSTEM

display to

reset.)

The outlet water temperature has exceeded
the setting of the manual reset high limit.

• Adjust the set point of the manual reset limit to a higher
setting up to a maximum of 210°F. Reference the
Knight Wall Mount Installation and Operation Manual for
adjusting procedures.

• Verify that the system is full of water and that all air
has been properly purged from the system.

• Verify that the boiler is piped properly into the heating
system. Refer to Section 6 - Hydronic Piping of the
Knight Wall Mount Installation and Operation Manual
for the proper piping methods for the wall mount boiler.

• Check 120 vac to boiler pump motor on a call for
heat. If voltage is not present, check wiring back to
the main control board.

39

Service Manual

3 Troubleshooting

Table 3-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

• Replace the main control board if necessary.

• If 120 vac is present on a call for heat and the boiler
pump is not operating, replace the pump.

Outlet MRHL

(cont’d)

(will require a manual

reset once the condition
has been corrected. Press
the RESET button on the

SMART SYSTEM

to reset.)

display

The outlet water temperature has exceeded
the setting of the manual reset high limit.

• If the system pump is a variable speed pump, ensure
that the system flow is not less than the boiler flow.

• If operating on something other than an outlet sensor,
check temperature setting of the main control board.

• If the optional manual reset high limit has tripped,
check setting of the device.

• Check resistance of water sensors and compare to
Table 3-2A on page 35 of this manual. Replace
sensor if necessary.

• Replace high limit.

Fan Low/High

OR

Fan Speed Low/

High

(will require a manual

reset once the condition
has been corrected. Press
the RESET button on the

SMART SYSTEM

to reset.)

display

GV/Relay

Fail

(will require a manual

reset once the condition
has been corrected. Press
the RESET button on the

SMART SYSTEM

to reset.)

display

The actual fan RPM is 30% lower than what
is being called for.

Blown fuse.

The main control board did not detect the
gas valve.

• Vent/air intake lengths exceed the maximum allowed
lengths. Refer to Section 3 - General Venting of the
Knight Wall Mount Boiler Installation and Operation
Manual for proper lengths.

• Check for obstruction or blockage in the vent/air
intake pipes or at terminations.

• Check the wiring connections at the fan and at the
main control board.

• Replace the fan.

• Replace the main control board.

• Replace fuse F2 on the control board, see page 33
of this manual.

• Check wiring harness connection at the gas valve and
at the main control board.

• Replace the gas valve wire harness.

• Replace the gas valve.

• Replace the main control board.

Sensor Open

(will require a manual

reset once the condition
has been corrected. Press
the RESET button on the

SMART SYSTEM

to reset.)

display

40

Either the inlet water or outlet water
temperature sensor has been disconnected.

• Check the sensors and their associated wiring.
Repair or replace the sensor or wiring if damaged.

• Measure the resistance of the sensors and compare
the resistance to the tables on page 35 of this
manual.

• Replace the sensor if necessary.

Service Manual

3 Troubleshooting (continued)

Table 3-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

• Check the sensors and their associated wiring.

Sensor Shorted

(will require a manual reset

once the condition has been

corrected. Press the RESET

button on the SMART

SYSTEM

display to reset.)

Louver Proving

Sw

(will require a manual reset

once the condition has been

corrected. Press the RESET

button on the SMART

SYSTEM

display to reset.)

Either the inlet water or outlet water
temperature sensor has been shorted.

An optional remote proving switch is not
making.

Repair or replace the sensor or wiring if damaged.

• Measure the resistance of the sensors and compare
the resistance to the tables on page 35 of this
manual.

• Replace the sensor if necessary.

• Check function of remote devices.

• Check for loose or misplaced jumper if auxiliary
proving switch is not installed.

Inlet Sensor

Fault

(will require a manual reset

once the condition has been

corrected. Press the RESET

button on the SMART

SYSTEM

display to reset.)

Outlet Sensor

Fault

(will require a manual reset

once the condition has been

corrected. Press the RESET

button on the SMART

SYSTEM

display to reset.)

Outlet Temp Diff

(will require a manual reset

once the condition has been

corrected. Press the RESET

button on the SMART

SYSTEM

display to reset.)

The control reads the inlet sensor as open
or shorted.

The control reads the inlet sensor as open
or shorted.

The control module reads an excessive
temperature difference between the two
sensors.

• Check wiring to sensor. Make sure wiring is
connected and not damaged. Reconnect / repair
wiring if necessary.

• Measure the resistance of the sensor and compare to
the resistance in Table 3-2A on page 35 of this manual.
Replace sensor if necessary.

• Replace control module.

• Check wiring to sensor. Make sure wiring is
connected and not damaged. Reconnect / repair
wiring if necessary.

• Measure the resistance of the sensor and compare to
the resistance in Table 3-2C on page 35 of this manual.
Replace sensor if necessary.

• Replace control module.

• Check wiring to sensor. Make sure wiring is
connected and not damaged. Reconnect / repair
wiring if necessary.

• Measure the resistance of the sensor and compare to
the resistance in Table 3-2C on page 35 of this manual.
Replace sensor if necessary.

• Restore control parameter defaults from optional PC
software.

• Replace control module.

41

Service Manual

3 Troubleshooting

Table 3-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

• Check wiring to sensor. Make sure wiring is

Flue Sensor Fault

(will require a manual reset

once the condition has been

corrected. Press the RESET

button on the SMART

SYSTEM

display to reset.)

Flue Temp Diff

(will require a manual reset

once the condition has been

corrected. Press the RESET

button on the SMART

SYSTEM

display to reset.)

The control reads the flue sensor as open
or shorted.

The control module reads an excessive
temperature difference between the two
sensors.

connected and not damaged. Reconnect / repair
wiring if necessary.

• Measure the resistance of the sensor and compare
to the resistance in Table 3-2D on page 35 of this
manual. Replace the sensor if necessary.

• Replace control module.

• Check wiring to sensor. Make sure wiring is
connected and not damaged. Reconnect / repair
wiring if necessary.

• Measure the resistance of the sensor and compare to
the resistance in Table 3-2D on page 35 of this
manual. Replace sensor if necessary.

• Restore control parameter defaults from optional PC
software.

Flue Temp Limit

(will require a manual reset

once the condition has been

corrected. Press the RESET

button on the SMART

SYSTEM

display to reset.)

Fatal Error

The stack temperature has exceeded the
Flue Temp Limit set parameters.

The control module has detected parameter
settings that are out of range.

• Replace control module.

• Inspect the heat exchanger. Reference page 32 of
this manual for the procedure on how to clean the flue
side of the heat exchanger.

• Inspect the flue sensor and associated wiring.
Measure the resistance of the flue sensor and
compare to Table 3-2D on page 35 of this manual.
Replace the sensor if necessary.

• Verify that the vent/air intake pipes are properly
installed and that there are no obstructions.

• Replace the main control board.

• Restore the parameter defaults from the optional PC
software.

• Replace control module.

Memory Error

42

A lockout occurs at the same time as a
power outage.

• Reset control module.

Service Manual

3 Troubleshooting (continued)

Table 3-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

• Inspect the heat exchanger. Reference page 32 of
this manual for the procedure on how to clean the flue
side of the heat exchanger.

• Inspect the flue sensor and associated wiring.
Measure the resistance of the flue sensor and

Flue Temp High

The stack temperature has exceeded the set
parameters for the boiler.

compare to Table 3-2D on page 35 of this manual.
Replace the sensor if necessary.

• Verify that the vent/air intake pipes are properly
installed and that there are no obstructions.

• Replace the main control board.

• Verify that the system is full of water and that all air
has been properly purged from the system.

Delta T High

Outlet Temp

High

The temperature rise across the heat
exchanger has exceeded the set parameters
for the boiler.

Outlet water temperature has exceeded the
maximum outlet water temperature.

• Verify that the boiler is piped properly into the heating
system. Refer to Section 6 - Hydronic Piping of the
Knight Wall Mount Boiler Installation and Operation
Manual for the proper piping methods for the wall mount
boiler.

• Check for 120 vac to the boiler pump motor on a call
for heat. If voltage is not present, check the wiring
back to the main control board. Replace the main
control board if necessary.

• If 120 vac is present on a call for heat and the boiler
pump is not operating, replace the pump.

• Verify that the boiler pump is set to the proper speed
or that the pump is the proper size. Reference
Section 6 - Hydronic Piping of the Knight Wall Mount
Boiler Installation and Operation Manual for boiler
pump specifications.

• Verify that the system is full of water and that all air
has been properly purged from the system.

• Verify that the boiler is piped properly into the heating
system. Refer to Section 6 - Hydronic Piping of the
Knight Wall Mount Boiler Installation and Operation
Manual for the proper piping methods for the wall
mount boiler.

• Check for 120 vac to the boiler pump motor on a call
for heat. If voltage is not present, check wiring back
to the main control board. Replace the main control
board if necessary.

• If 120 vac is present on a call for heat and the boiler
pump is not operating, replace the pump.

43

Service Manual

3 Troubleshooting

Table 3-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

• Verify that the boiler pump is set to the proper speed

Outlet Temp

High

(continued)

Rem Ctrl Flt

Outlet water temperature has exceeded the
maximum outlet water temperature.

External control is cycling too often.

or that the boiler pump is the proper size. Reference
Section 6 - Hydronic Piping of the Knight Wall Mount
Boiler Installation and Operation Manual for boiler
pump specifications.

• Replace the main control board.

• Check set point of the external control.

• Check the wiring between the external control and the
unit.

• Replace the control.

Parameters

Progr

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the
SMART SYSTEM

to reset.)

display

Service Blk

After downloading parameters from a laptop,
the main control board must be reset.

While the unit is in Service Mode, the outlet
temperature has exceeded 185°F.

• Press the ENTER/RESET button on the SMART
SYSTEM display panel.

• Establish a heating load to remove the heat from the
boiler loop.

• Verify that the system is full of water and that all air
has been properly purged from the system.

• Verify that the boiler is piped properly into the heating
system. Refer to Section 6 - Hydronic Piping of the
Knight Wall Mount Installation and Operation Manual
for the proper piping methods for the Knight wall mount
boiler.

• Check 120 vac to the boiler pump motor on a call for
heat. If voltage is not present, check the wiring back
to the main control board. Replace the main control
board if necessary.

44

• If 120 vac is present on a call for heat and the boiler
pump is not operating, replace the pump.

• Verify that the boiler pump is set to the proper speed
or that the boiler pump is the proper size. Reference
Section 6 - Hydronic Piping of the Knight Wall Mount
Boiler Installation and Operation Manual for boiler
pump specifications.

Service Manual

3 Troubleshooting (continued)

Table 3-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

Low 24 vac

Watch Dog Error

Write EEProm

CRC Parameters

No Error Stored

120 vac input to the main control board has
dropped below 80 vac.

The main control board has detected an
internal fault.

The main control board has detected an
internal fault.

The main control board has detected an
internal fault.

The main control board has detected an
internal fault.

• Check 120 vac supply to the transformer.

• Check wiring connections at the low voltage
terminal strip.

• Check the wire size/length to remote devices.

• Replace the transformer.

• Replace the main control board.

• Replace the main control board.

• Replace the main control board.

• Replace the main control board.

45

3 Troubleshooting

Combustion Analysis Procedure

Service Manual

1. Turn the main power off to the boiler.

2. Remove the flue temperature sensor from the flue pipe
connection. Note: Combustion measurements will be
made at this point.

3. Turn the main power on to the boiler.

4. Place the boiler into the active position by pressing the
RIGHT SELECT [ON] key (see page 7).

5. Locate the pinhole button below the RESET button on

the display board (see page 7). Insert a thin wire (such as
a paper clip) into the hole and press the button once and
hold for 5 seconds to place the boiler into Service Mode.
In Service Mode the boiler will fire at ignition speed and
will then modulate up to full fire.

6. Insert the probe from a combustion analyzer into the

hole left by the removal of the flue temperature sensor.

7. Once the boiler has modulated up to full fire, measure

the combustion. The values should be in the range listed
in Table 3-6 above. The CO levels should be less than
150 ppm for a properly installed unit.

If the combustion is not within the specified range,

reference the chart below for possible causes and
corrective actions.

Table 3-6 Flue Products

Natural Gas Propane

CO

2

8.0% - 10% 3.0% - 6.5% 9.0% - 11% 4.1% - 6.9%

O

2

CO

2

O

2

8. Once the combustion analysis is complete, test the safety
shutoff device by turning the manual shutoff switch to
the OFF position and ensuring that the boiler shuts
down and registers an alarm. Turn the manual shutoff
switch to the ON position, reset the control, and return
to Service Mode.

9. Turn the main power off to the boiler and replace the flue
temperature sensor into the flue pipe connection.

10. Place the boiler back into normal operation.

 WARNING

You must replace the flue gas temperature
sensor to prevent flue gas spillage into the
room. Failure to comply could result in
severe personal injury, death, or substantial
property damage.

Table 3-5 Troubleshooting Chart - Combustion Levels

POSSIBLE CAUSE CORRECTIVE ACTION

• Refer to Section 3 - General Venting of the Knight Wall Mount Installation and Operation

Vent/Air Intake Length

Manual for the proper venting and air intake methods for the Knight wall mount boiler.

or Obstruction

• Check for obstructions at the vent/air intake terminals.

Gas Supply Pressure

• Refer to Section 7 - Gas Connections of the Knight Wall Mount Installation and Operation
Manual for the proper gas supply for the Knight wall mount boiler.

• Refer to page 31 of this manual for burner removal and cleaning procedures.

Dirty/Damaged Burner

• Replace burner if necessary.

Gas Valve Adjustment

• Refer to page 47 of this manual for the gas valve adjustment procedure.

46

3 Troubleshooting (continued)

Gas valve adjustment procedure

If adjustment of the gas valve is deemed necessary, use the
following procedures:

Locate the throttle adjustment screw on the side of the venturi
valve (FIG. 3-2). Using a screwdriver, turn the screw a 1/4 turn
clockwise to increase CO2 levels or a 1/4 turn counterclockwise
to decrease CO2 levels. After performing one adjustment on the
valve, follow the Combustion Analysis Procedure on page 46 of
this manual to measure the combustion.

If combustion is still not within the specified range, repeat
the procedure. This procedure SHOULD NOT be performed
more than four (4) times. If after four (4) adjustments and the
combustion is still not within the specified range, revisit the
possible causes in Table 3-5 on page 46 or replace the gas valve.

Figure 3-2 Gas Valve Adjustment

Service Manual

47

Revision Notes: Revision A (ECO #C05747) initial release. Reflects

the new model numbers for the Knight Wall Mount upgrade.
Revision B (ECO #C06234) reflects changes made to the Service

Notification parameter.
Revision C (ECO #C08372) reflects changes made to the parameter

table, parameter descriptions, addition of the rope gasket, and updates
to the troubleshooting chart.

WBII-SER-Rev C

6/11