Navien NHB-055H Guide

WARNING
If the information in these instructions is not followed exactly, a fire or explosion may result,
causing property damage, personal injury, or death.
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this
or any other appliance.
WHAT TO DO IF YOU SMELL GAS
●Do not try to light any appliance.
●Do not touch any electrical switch; do not use any phone in your building.
●Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s
instructions.
●If you cannot reach your gas supplier, call the fire department.
Installation and service must be performed by a qualified installer, service agency or the
gas supplier.
The installation must conform with local codes or, in the absence of local codes, the National Fuel
Gas Code, ANSI Z223.1/NFPA 54 and/or CSA B149.1, Natural Gas and Propane Installation Code.
ALWAYS read and follow this manual
completely before using the boiler.
Save for future reference.
User’s Information Manual
NHB-H Condensing Boilers
Model NHB-055H
NHB-080H
NHB-110H
NHB-150H

2Contents
Contents
1. Important Safety Information 3
2. About the Boiler 6
2.1 Description of the Boiler 6
2.2 Parts of the Boiler 6
2.3 The Front Panel 7
3. Operating the Boiler 9
3.1 Turning the Boiler On or Off 9
3.2 Adjusting the System Temperatures 9
3.3 Accessing Basic Menu Items 13
3.4 Resetting the Boiler 14
4. Maintaining the Boiler 15
4.1 Cleaning the Boiler 15
4.2 Draining the Boiler 15
4.3 Cleaning the Air Intake Filter 16
4.4 Protecting the Boiler from Freezing 17
4.5 Maintenance Schedules 18
5. Troubleshooting 23
5.1 Solving Basic Problems 23
5.2 Understanding Error Codes 24
6. LIMITED WARRANTY NAVIEN, INC. 25
Product Installation Information
Model
Date Purchased
Gas Type
Serial Number

3Important Safety Information
The following Safety Alert Symbols are used
in this manual. They are used to alert you
to potential personal injury hazards. Obey
all safety messages that follow this symbol to avoid
possible serious injury or death. This Safety Alert
Symbol precedes any safety message about risk of
personal injury. It may also be accompanied by one
of the following signal words.
If the information in these instructions is not
followed exactly, a fire or explosion may result,
causing property damage, personal injury or death.
DANGER
Indicates a hazardous situation that if not
avoided will result in death or serious injury.
WARNING
Indicates a hazardous situation that if not
avoided could result in death or serious injury.
CAUTION
Indicates a potentially hazardous situation that
if not avoided could result in minor or moderate
injury.
NOTICE
Indicates information considered important but
not hazard-related (such as property damage).
DANGER
If you do not follow these instructions exactly,
a fire or explosion may result causing property
damage, personal injury or loss of life.
A. This appliance does not have a pilot. It is
equipped with an ignition device which
automatically lights the burner. Do not try
to light the burner by hand.
B. BEFORE OPERATING smell all around the
appliance area for gas. Be sure to smell next
to the floor because some gas is heavier
than air and will settle on the floor.
WHAT TO DO IF YOU SMELL GAS
●Do not try to light any appliance.
●Do not touch any electric switch; do not
use any phone in your building.
●Immediately call your gas supplier from
a neighbor’s phone. Follow the gas
supplier’s instructions.
●If you cannot reach your gas supplier, call
the fire department.
●Do not return to your home until
authorized by your gas supplier or the
fire department.
C. Do not use this appliance if any part has
been under water. Immediately call a
qualified service technician to inspect the
appliance and to replace any part of the
control system and any gas control which
has been under water.
1. Important Safety Information

4Important Safety Information
WARNING
To prevent death, serious injury, or property
damage:
●Shut off the gas supply if the boiler is
damaged.
Have your installer or plumber show you
the location of the gas shut off valve and
demonstrate how to close the valve. If the boiler
is damaged as a result of overheating, fire, flood,
or any other reason, close the manual shut off
valve and do not operate the boiler again until
it has been inspected by a qualified technician.
●Do not store or use gasoline or other
flammable liquids near this boiler.
Doing so may result in fire or explosion.
●Do not place combustibles, such as
newspapers or laundry, near the boiler or
venting system.
Doing so may result in a fire.
●Do not place or use hair sprays, spray paints,
or any other compressed gases near the
boiler or venting system, including the vent
termination.
Doing so may result in fire or explosion.
●Do not operate the boiler with the front
cover opened.
Doing so may result in fire or carbon monoxide
(CO) poisoning, which may result in property
damage, personal injury, or death.
●Do not operate this boiler without proper
venting.
Doing so may result in fire or carbon monoxide
(CO) poisoning, which may result in property
damage, personal injury, or death. Inspect the
vent termination and air intake supply annually
to ensure proper operation of the boiler. Turn
off and discontinue use of the boiler if any of
the vent pipes, vent elbows, or intake pipes are
damaged in any way, separated at a joint, or
show evidence of corrosion, rusting, or melting.
WARNING
To prevent death, serious injury, or property
damage:
●Do not touch the power cord or internal
components of the boiler with wet hands.
Doing so may result in electric shock.
●Do not make any electrical connections
before turning off the electrical power
supply at service entrance panel.
Doing so may result in severe personal injury
or death.
California law requires the following Prop 65
warning to be provided:
WARNING
Cancer and Reproductive Harm -
www.P65Warnings.ca.gov

5Important Safety Information
WARNING
●Do not attempt to repair or replace any
part of the boiler, unless it is specifically
recommended in this manual.
For all other service, contact an authorized
technician or licensed professional. Improper
adjustments, alterations, service, or
maintenance may lead to property damage,
personal injury, or death and will void your
warranty.
●Do not operate the boiler if you feel
something is wrong with it.
Doing so may result in product damage or
personal injury.
●Do not allow children to operate or access
the boiler.
Doing so may result in product damage or
personal injury.
●Do not turn on the boiler unless the water
and gas supplies are fully opened.
Doing so may damage the boiler.
●Do not use this boiler for anything other
than its intended purpose, as described in
this manual.
●Do not remove the front cover unless
the power to the boiler is turned off or
disconnected.
Failure to do so may result in electric shock.
●When servicing the controls, label all wires
prior to disconnecting them.
Failure to do so may result in wiring errors,
which can lead to improper or dangerous
operation.
●Do not use unapproved replacement or
accessory parts.
Doing so may result in improper or dangerous
operation and will void the manufacturer’s
warranty.
●Do not place anything in or around the vent
terminals, such as a clothes line, that could
obstruct the air flow in or out of the boiler.
●This boiler has been approved for use in the
USA and Canada only.
Using the boiler in any other country will void
the manufacturer’s warranty.
●Should overheating occur or the gas supply
fail to shut off, turn off the manual gas
valve to the appliance.

6About the Boiler
2.1 Description of the Boiler
The Navien NHB-H boiler is available in 4 models:
NHB-055H, NHB-080H, NHB-110H and NHB-150H.
The main features are as follows:
●Power Interruption: When the power is restored
after a power failure, the boiler will automatically
start and return to normal operation. A manual
reset is not required.
●Short-Circuit Protection: Any short-circuit
occurring in the boiler’s electrical circuit
immediately blows the internal glass fuses and
automatically cuts off the gas supply.
●Lightning Protection: Each boiler is specially
grounded, both internally and externally, to
protect against lightning strikes.
●Auto Fan Detection: The rotation of the fan is
automatically detected and controlled. Fan failure
will stop the operation of the boiler.
●Boiling Prevention: Excessive temperatures will
automatically stop the boiler.
2.2 Parts of the Boiler
2.2.1 Front View
Exhaust
Gas Vent
Combustion
Air Intake
2.2.2 Bottom View
A
B
C
D
E
#Description
ARubber Grommets
BGas Connection
CSpace Heating Supply Connection
DCondensate Outlet
ESpace Heating Return Connection
2. About the Boiler

7About the Boiler
2.3 The Front Panel
The front panel allows you to adjust the
temperature and view the operating status or error
codes. Remove the protective sheet from the front
panel before using it.
2.3.1 Icons and Digital Display
The icons and digital display on the front panel
provide important information required for the
boiler’s operation. Refer to the following table for
detailed information.
aOutdoor reset Displayed when the Outdoor
Reset feature is enabled.
bCombustion Displayed when the burner is
combusting.
c
System check or error
Displayed when an error is
detected or a system check is
needed due to service alarm
overtime.
d
Freeze Protection
Displayed when the boiler
is operating in Freeze
Protection mode.
Auto air purge
Displayed when an auto air
purge is being performed.
e
Cascade/Main mode
Flashes when configuring a
cascade system. Turns on solid
if the boiler is set as the Main
unit in a cascade system.
fDHW priority Displayed when the DHW
Priority feature is enabled.
AHU connection
Displayed when the AHU
connection settings are
enabled. If there is a problem
or a connection is being
made, this icon will blink.
gDHW demand Indicates that DHW
demand is present.
hDHW temperature Displays the set and current
DHW temperature.
i
System pressure
Displays the internal water
pressure of the boiler
system.
jOutdoor temperature Displays the outdoor
temperature.
k
Space heating
temperature
Displays the set and
current space heating
temperature.
l
Space heating demand
Indicates the space heating
demands from thermostats
1, 2, and 3.
b
a
d
f
c
l
k
j
g
i
e
h

8About the Boiler
2.3.2 Buttons and Command Dial
Using the buttons and the Command dial ( ) on
the front panel, you can turn on or off the boiler,
monitor the current operation status, and set the
values required for the boiler’s operation, such as
space heating and DHW supply temperatures. Refer
to the following table for detailed information.
aBack button Return to the previous menu
or screen.
bMode button
Enter the boiler’s main menu.
cPower button
Turn on or off the boiler. d
Command dial
Rotate to switch between
menu items, or to increase/
decrease values.
Press to make a selection or
to confirm changes.
c
b
d
a

9Operating the Boiler
WARNING
To prevent death, serious injury or property damage:
●Ensure that the boiler is filled with water before turning it on.
●If overheating occurs or the gas supply fails to shut off, shut off the gas supply to the boiler by using the
manual gas valve.
●If any part of the boiler has been submerged in water, do not use this appliance and immediately call a
qualified service technician. The boiler must be replaced.
3.1 Turning the Boiler On or Off
To turn the boiler on or off, press the Power button ( ).
When the power is on, the boiler automatically enters normal operation mode, and the boiler’s operating
conditions are displayed on the screen.
Note The boiler status icons remain displayed when the boiler is turned off.
3.2 Adjusting the System Temperatures
Navien NHB-H boilers include multi-temperature zone priority feature that allows the boiler to operate at up
to 3 different temperatures. This built-in feature can be accessed from the front panel and eliminates the need
for additional accessories that are typically required for multi-temperature applications when used with a
combination of heating sources such as baseboard, in-floor heating, and/or an indirect DHW tank.
The boiler can be set up to adjust the priority based on the desired zone temperatures.
In normal operation mode, space heating temperature for each zone can be set depending on the settings in the
following table.
Settings Space heating settings
Zone Priority Settings Zone Settings Pump 1 Settings
Disable N/A N/A Space heating temperature settings
Enable Zone Pump System DHW Pump
Space heating temperature settings
for Zone 2 and Zone 3 (Pump 1
Settings”is set to“DHW Pump”.)
Enable Zone Pump System Zone1 Pump Space heating temperature settings
for Zone 1, Zone 2 and Zone 3
Enable Zone Valve System DHW Pump (Default) Space heating temperature settings
for Zone 1, Zone 2 and Zone 3
3. Operating the Boiler

10 Operating the Boiler
3.2.2 Adjusting the Space Heating
Temperature (When “3. Zone Priority
Setting”is enabled)
To adjust the heating temperature:
1. In normal operation mode, rotate the Command
dial ( ). The space heating temperature ( ) is
highlighted on the screen.
3.2.1 Adjusting the Space Heating
Temperature (When “3. Zone Priority
Setting”is disabled)
To adjust the heating temperature:
1. In normal operation mode, rotate the Command
dial ( ). The space heating temperature ( ) is
highlighted on the screen.
2. Press the Command dial ( ) to select the space
heating temperature. The highlighted section
will flash.
3. Rotate the Command dial ( ) to the right or
left to increase or decrease the temperature.
4. Press the Command dial ( ) to confirm the
new temperature.
5. Press the Back button ( ) to return to normal
operation mode, or rotate the Command dial
() to adjust other operation conditions.
You can adjust the temperature while the
highlighted section is flashing. Once the flashing
stops, the current temperature setting is stored.

11Operating the Boiler
2. Press the Command dial ( ) to select the desired zone, and then press the Command dial ( ). The selected
zone’s temperature will flash.
Note The number of the zones differs depending on the zone settings and Pump 1 settings.
Zone Settings Pump1 Settings Space heating settings for each zone
N/A N/A Space heating temperature settings
Zone Pump
System DHW Pump Space heating temperature settings for Zone 2 and Zone 3
(Pump 1 Settings”is set to “DHW Pump”.)
Zone Pump
System Zone1 Pump Space heating temperature settings for Zone 1, Zone 2 and
Zone 3
Zone Valve
System
DHW Pump
(Default)
Space heating temperature settings for Zone 1, Zone 2 and
Zone 3
3. Rotate the Command dial ( ) to the right or left to increase or decrease the selected zone’s space heating
temperature.
4. Press the Command dial ( ) to confirm the new temperature.
5. Press and hold the Command dial ( ) for more than 2 seconds to return to normal operation mode, or
rotate the Command dial ( ) to adjust another zone’s temperature.
Note ●The space heating temperature cannot be adjusted when the Outdoor Reset Control is used.
●The space heating temperature cannot be adjusted if the boiler is operating as a sub unit in a
cascade system. The main unit’s set temperature will be displayed on the screen.
●In case of outdoor reset sensor malfunction, the boiler will operate at this set temperature.
●Take note of the original heating temperature in case you want to restore it to the default.
●The default space heating supply water temperature range is 104°F (40°C, Absolute MIN) to 180°F
(82°C, Absolute MAX).
●The default space heating return water temperature range is 86°F (30°C, Absolute MIN) to 149°F
(65°C, Absolute MAX).
●You can adjust the temperature ranges in the parameter settings menu.
●The boiler will retain your settings during a power outage.

12 Operating the Boiler
3. Press the Command dial ( ) to select the
indirect DHW temperature ( ). The highlighted
section will flash.
4. Rotate the Command dial ( ) to the right or
left to increase or decrease the temperature.
5. Press the Command dial ( ) to confirm the
new temperature.
6. Press the Back button ( ) to return to normal
operation mode, or rotate the Command dial to
adjust other operation conditions.
You can adjust the temperature while the display is
flashing. Once the display stops flashing, the current
temperature setting is stored.
Note ●Take note of the original DHW indirect
supply temperature in case you want
to restore it to the default.
●The default DHW temperature range
is 104°F (40°C, Absolute MIN) to 180°F
(82°C, Absolute MAX).
●You can adjust the temperature ranges
in the parameter settings menu.
●The boiler will retain your settings
during a power outage.
3.2.3 Adjusting the DHW Indirect
Supply Temperature
DANGER
Water temperatures at or above 125°F (52°C) can
cause instant scalding, severe burns, or death.
Before you decide to change the temperature
setting, read the following table carefully.
Water
Temperature
Time in which a young child can
suffer a full thickness
(3rd degree) burn
160°F (70°C) Less than 1 second
140°F (60°C) 1 second
130°F (55°C) 10 seconds
120°F (49°C) 10 minutes
100°F (37°C) very low scald risk
To adjust the water temperature:
1. In normal operation mode, rotate the Command
dial ( ). The space heating temperature ( ) is
highlighted on the screen.
2. Rotate the Command dial ( ) to the right to
select the DHW temperature.

13Operating the Boiler
Item Description
5. AHU SH Set Temp
Note
Use with iFlow Air
Handlers Only.
AHU Space Heating Set
Temperature (°F)
●If AHU is not connected,
“--”will be displayed.
●The temperature is
displayed by 1 degree
increments for Fahrenheit
and by 0.5 degree
increments for Celsius.
This is due to the degree
control specifications of
0.5 degree for the AHU
communication type.
6. Supply Temp Heating supply
temperature (°F)
7. Return Temp Boiler return temperature
(°F)
8. Sys Supply Temp System supply
temperature (°F)
9. Sys Return Temp System return
temperature (°F)
10. Outdoor Temp Outdoor temperature (°F)
11. Approx. Boiler
Flow Flow rate (GPM)
12. DHW Tank set
Temp
DHW Tank set temperature
(°F)
13. Tank Sensor
Temp
DHW indirect tank
temperature (°F)
14. Water Press Water pressure (psi)
15. Flame Value
Flame detector AD value
●Flame On: 8bit AD
values equal to or lower
than 70
●Flame Off: 8bit AD
values equal to or
higher than 175
16. Fan Target RPM Set fan speed (RPM)
17. Fan Current RPM Fan speed (RPM)
18. Fan Target APS Set APS voltage (V)
19. Fan Current APS APS voltage (V)
20. Exhaust Temp Exhaust temperature (°F)
21. Outdoor Reset Outdoor reset status
(Enable / Disable)
3.3 Accessing Basic Menu Items
In the Menu Select screen, you can view the boiler’s
operating conditions, configure the space heating
and DHW temperatures, and review error history.
Press the Menu button ( ) to enter the Main Menu
screen.
To view information about the boiler, press the
Menu button ( ), and then select“1. Status
Information”.
Rotate the Command dial ( ) to switch between
the information items. Press the Command dial ( )
to select an item and view the information.
Press the Back button ( ) to exit information view
mode.
Item Description
1. Operation State Current Operation State
2. Heat Capacity Heat Capacity (%)
3. SH Set Temp Space heating set
temperature (°F)
4. DHW Set Temp DHW indirect supply set
temperature (°F)

14 Operating the Boiler
3.4 Resetting the Boiler
If an error message appears during boiler operation,
reset the boiler to resolve the problem. Press the
Back button ( ) on the front panel to reset the
boiler.
If resetting the boiler does not solve the problem,
refer to the Troubleshooting section of this manual
or contact Technical Support at 1-800-519-8794.
Item Description
22. Outdoor Reset
Curve
Outdoor reset curve load
type (displayed when the
outdoor reset option“21.
Outdoor Reset” is enabled)
1: Finned Tube Baseboard
2: FAN Coil
3: Cast Iron Baseboard
4: Low Mass Radiant
5: High Mass Radiant
6: Radiator
7: Custom (set by
installer)
23. Boost Interval
Time
Boost interval set time
(min)
24. High Altitude
Sea Level (0–2,000 ft)
Level 1 (2,000–5,400 ft)
Level 2 (5,400–7,700 ft)
Level 3 (7,700–10,100 ft)
25. Model Model type
26. Gas Fuel type (NG/LPG)
27. Main F/W Ver Firmware version of the
main controller
28. Panel F/W Ver Firmware version of the
panel controller

15Maintaining the Boiler
4.1 Cleaning the Boiler
CAUTION
Scald Hazard
To prevent scalding:
Make sure the boiler is turned off and the power
supply is disconnected before cleaning the
boiler. The boiler may remain hot for several
minutes after it is turned off. To prevent burns,
wait until the boiler has cooled down before
cleaning.
To clean the boiler, wipe the outside with a damp
cloth. Use a non-acidic, non-abrasive cleaner
to remove any surface stains. The front panel is
moisture resistant, but it is not waterproof. Keep it as
dry as possible.
4.2 Draining the Boiler
You will need to drain the boiler under certain
circumstances such as when the boiler is not used
for an extended period of time in order to prevent
freeze damage.
Refer to“2.2 Parts of the Boiler”on page 6 for
details about part locations.
To drain the boiler:
1. Place a bucket under the boiler to collect the
residual water inside the boiler.
2. Press the Power button ( ) on the front panel
to turn off the boiler.
3. Close the gas valve.
OPEN
CLOSE
OPEN
CLOSE
OPEN
CLOSE
Gas
Valve
Open Closed
4. Close the water supply valve and the return
valves on the manifold system.
4. Maintaining the Boiler

16 Maintaining the Boiler
4.3 Cleaning the Air Intake Filter
If the air intake filter becomes clogged by dust
or lint, the boiler will cease to operate and “Error
Code 110”will appear on the front panel display.
To properly maintain the boiler, clean the air
intake filter as needed or as part of the annual
maintenance.
To clean the air intake filter:
1. Press the Power button ( ) on the front panel
to turn off the boiler.
2. Disconnect the power supply to the boiler.
3. Unfasten the 4 latches (2 at the top and 2 at the
bottom) to remove the front cover.
5. Remove the drain cap and open the purge valve
on the manifold system to drain the boiler.
Purge Valve
1
2
Drain Cap
Note ●Place a bucket under the boiler
to gather water released from the
manifold system.
●Do not allow the pump to become
wet.

17Maintaining the Boiler
4.4 Protecting the Boiler from
Freezing
NOTICE
Damage due to freezing is not covered by the
Navien limited warranty.
●Freezing damage is most likely to occur due
to back drafting caused by negative pressure
in the building. This is not a manufacturing
defect, and therefore, Navien will not
warrant any damages due to freezing. The
installer is responsible for ensuring that
there is sufficient make-up air to avoid such
a situation and the owner is responsible for
ensuring that protection against freezing is
maintained.
●To avoid freezing issues, we strongly
recommend the use of a direct vent exhaust
and intake system. Your installer should
ensure that the exhaust vent pipe and the
air intake pipe are both connected directly
from the collars on the top of the boiler to the
outdoors. This type of vent system minimizes
air movement within the boiler.
●This boiler has an optional recirculation mode
that is used for freeze protection. This mode
should prevent the boiler from freezing, even
if the intake air duct is not vented directly.
●The boiler is designed for indoor installation
only.
To ensure that the boiler does not freeze, follow
these guidelines:
●Do not unplug the power supply cord, except
for routine maintenance. The boiler has a freeze
protection function that requires power. The
freeze protection function will operate regardless
of whether or not the power is turned on or in
standby mode, as long as the power supply is still
connected.
●Do not close the gas valve, except for routine
maintenance, as this will limit additional freeze
protection.
●If the boiler will not be used for an extended
period, drain the boiler.
If the power or gas supplies must be
disconnected for an extended period, drain the
boiler. Freezing damage may occur if there is
water remained in the boiler in cold weather.
4. Remove the screw that secures the air intake
filter (the filter is located at the top left of the
boiler).
5. Pull the filter out of the boiler.
6. Remove the filter from the plastic assembly.
Dust and rinse it with clean running water.
7. Allow the filter to dry completely.
8. Place the filter assembly back into the boiler and
secure it with the screw.
9. Replace the front cover.
10. Reconnect the power supply to the boiler.
11. Press the Power button ( ) on the front panel
to turn on the boiler.

18 Maintaining the Boiler
Service technician (See the following instructions)
Annual Start-up
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 rod (clean and
reposition).
●Check wiring and
connections.
●Inspect flame (stable,
uniform).
●Inspect flame signal.
If combustion or
performance indicate need:
●Flush heat exchanger.
●Remove and clean air
intake filter.
Note ●If hot water will not flow and you
suspect that the boiler is frozen,
contact an authorized technician or
licensed professional.
●This boiler requires very little
maintenance, however a qualified
technician should inspect the boiler at
the beginning of every heating season
and/or when there is a problem.
4.5 Maintenance Schedules
Owner maintenance
Daily
●Check the boiler area is free
of combustible/flammable
materials and air contaminants.
●Check the pressure/temperature
gauge for signs of higher than
normal pressure.
Monthly
●Visually inspect the vent
piping for signs of leakage and
blockage.
●Visually inspect the burner
flames.
●Inspect the condensate trap and
the PVC fittings.
Periodically ●Test the LWCO for proper
operation.
Every 6
months
●Inspect boiler piping (gas and
water) for leaks.
●Test to make sure the relief valve
is operating normally.
Non-
heating
season
●Shut boiler down (unless boiler
is used for domestic hot water).

19Maintaining the Boiler
Inspecting the Boiler Interior
1. Remove the front cover and inspect the interior
of the boiler.
2. Vacuum any sediment from inside the boiler
and components. Remove any obstructions.
Cleaning the Condensate Trap
1. Inspect the condensate drain line, condensate
fittings, and condensate trap.
2. Remove any sediment in the trap.
3. Fill with fresh water until the water begins to
pour out of the drain.
Checking all Piping for Leaks
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.
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.
Checking the 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 (if installed).
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.
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 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
manual. Failure to turn off electrical power
could result in electrical shock, causing
severe personal injury or death.
Addressing the Reported Problems
Inspect any problems reported by the owner and
correct before proceeding.
Inspecting the Installation 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 the 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, refer to the
Installation and Operation Manual and re-install
the air and vent lines.

20 Maintaining the Boiler
WARNING
●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.
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.
Checking the 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 6 psi).
3. Watch the system pressure as the boiler heats
up (during testing) to ensure pressure does not
rise too high.
Note ●If the system contains glycol,
test for proper concentration as
recommended by manufacturer.
●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.
5. Replace caps. Make sure vents do not leak.
Replace any leaking vents.
Checking Expansion Tank
●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.
●Perform annual checks as recommended by
manufacturer to ensure proper operation.
Checking the Pressure Relief Valves
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.
Note Safety relief valves should be 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.