Lochinvar KNIGHT 399 - 800 User manual

Service Manual
Models: 399 - 800
This manual must only be
used by a qualified heating
installer / service technician.
Read all instructions,
including this manual and the
Knight XL 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.
WARNING
Save this manual for future reference.
KBX-SER Rev E

2
Hazard definitions
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.
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 Boiler 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-16
Viewable and Changeable Control Parameters . . . . . . . 17-22
2. MAINTENANCE
Maintenance and Annual Startup . . . . . . . . . . . . . . . . . . 23-27
3. TROUBLESHOOTING
Before Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Check Control Module Fuses . . . . . . . . . . . . . . . . . . . . . 28
Table 3A - Troubleshooting Chart - No Display . . . . . . . . 29
Checking Temperature Sensors . . . . . . . . . . . . . . . . . . . 30
Table 3E - Troubleshooting Chart - Noisy System . . . . . 31
Table 3F - Troubleshooting Chart - Fault Messages . . . . 32-39
Combustion Analysis Procedure . . . . . . . . . . . . . . . . . . . 40
Table 3G - Troubleshooting Chart - Combustion Levels 40
Table 3H - Flue Products . . . . . . . . . . . . . . . . . . . . . . . . . 40
Gas Valve Adjustment Procedure . . . . . . . . . . . . . . . . . . 41
Revision Notes . . . . . . . . . . . . . . . . . . . . . . . . . Back Cover
Contents

Service Manual
Please read before proceeding
Installer – Read all instructions,
including this manual and the Knight XL
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 XL 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.
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
XL Installation and Operation Manual).
Any claims for damage or shortage in
shipment must be filed immediately against
the transportation company by the
consignee.
3
Handling ceramic fiber materials
REMOVAL OF COMBUSTION CHAMBER LINING
The combustion chamber door insulation in this product 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 inhaled in the form of quartz or cristobalite
from occupational sources is carcinogenic to humans (Group 1).”:
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 boiler 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.
WARNING NOTICE
WARNING

4
Service Manual
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.
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.

Service Manual
5
What is in this manual?
Service
Near boiler piping
• Typical system components
The Knight XL 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 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 XL operation
• A: General
• B: Temperature Setting
• C: Data Logging
• D: Functions
• E: DHW Settings
• F: Outdoor Air Reset Curve
• G: Anti-cycling
• H: Control Modes
• I: Circulation Pumps
• J: 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

1 Service
6
Service Manual
FROM
R
TO
INDIRECT
DOMESTIC
HOT WATER
TANK
TO FLOOR
DRAIN
TO
SYSTEM
FROM
SYSTEM
BOILER PUMP
DOMESTIC HOT
WATER PUMP
SYSTEM PUMP
Near boiler piping
This piping reference is included to specify the Near Boiler Piping specific to the Knight XL. This piping scheme is important
for proper operation of the SMART SYSTEM control. See the Knight XL Installation and Operation Manual for more detailed
piping diagrams.

Service Manual
7
1 Service (continued)
• Hold 5 seconds to enter code
Input Mode (Menu Mode)
• Press to move up one level
in Menu Mode or to exit
Menu Mode
• Press to turn boiler off or
back on
• Press to select a menu item
• Press after parameter programming
to store parameter data
• Press to exit Service Mode
• Press to toggle display during normal
operation to show outlet and return
temperatures, fan speed, and flame
signal
• Press to toggle between digits when
entering access code or between hour,
minutes, etc., when entering date and
time
• Press to change boiler water
temperature set point during
normal operation
• Press to change displayed data
values in Menu Mode
• Press to navigate through menu
listing in Menu Mode
DISPLAY SCREEN
MENU / EXIT
SHUTDOWN
ENTER / RESET
SERVICE
BUTTON
PC
CONNECTION
PORT
NEXT
PREVIOUS
DOWNUP
The Knight XL display

1 Service
8
Service Manual
1 Service
GAS PRESSURE SWITCH
(OPTIONAL)
DHW THERMOSTAT
(OPTIONAL)
ROOM THERMOSTAT /
ZONE CONTROL
FLOW SWITCH
SYSTEM SENSOR
OUTDOOR SENSOR
(OPTIONAL)
SEQUENCER / BUILDING
MANAGEMENT SYSTEM
(OPTIONAL)
LOW VOLTAGE
CONNECTION
BOARD
INLET TEMPERATURE
SENSOR
OUTLET TEMPERATURE
SENSOR
FLUE GAS SENSOR
HIGH LIMIT
FLAME SENSOR
LOW WATER CUTOFF
(OPTIONAL)
BLOCKED DRAIN SWITCH
DISPLAY PANEL
PC INTERFACE
(OPTIONAL)
SMART CONTROL
MODULE
DHW TANK SENSOR
(OPTIONAL)
AIR PRESSURE SWITCH
Control inputs

1 Service
Service Manual
9
1 Service (continued)
LOW VOLTAGE
CONNECTION
BOARD
SMART CONTROL
MODULE
ALARM BELL
AUX. DEVICE RELAY
RUN TIME CONTACTS
SEQUENCER / BUILDING
MANAGEMENT SYSTEM
BOILER PUMP
SYSTEM PUMP
DHW PUMP
IGNITOR
BLOWER
GAS VALVE
DISPLAY PANEL
PC INTERFACE
Control outputs

1 Service
10
Service Manual
1 Service
General Operation
How the boiler operates
The Knight XL 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 XL 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.
Sequence of operation
Table 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.
Access modes
User
The user can adjust space heating set point using the UP and
DOWN buttons at any time during normal operation. By
entering the USER code (0704), the user can also change
temperature units, time and date, and night setback settings.
In user mode, the following parameters can be viewed but not
changed: Boiler outlet water temperature in DHW mode;
boiler model number; software version; total operating hours,
and total cycles.
Installer
Most parameters are available only to the installer, accessible
only by entering the installer access code (5309).
Saving parameters
To save parameters:
Press the ENTER/RESET button.
To keep parameter settings only for a current operating cycle:
Press the MENU/EXIT button 1 time to return to the
parameter listings; press again to return to the menu listings.