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Description
a
Gas connection
b
Condensate water outlet
c
Space heating supply connection
d
DHW hot water outlet connection
e
Return adapt
ter
f
Cold water inlet connection
g
Space heating return connection
h
Pump drain plug
2.1 Description of the Boiler
The Navien NCB LDWE boiler is available in 4 models:
NCB-24LDWE, NCB-28LDWE, NCB-34LDWE and NCB-40LDWE.
The main features are as follows:
About the Boiler 7
2.2 Parts of the Boiler
Front View
Coaxial
(Intake/Exhaust)
Bottom View
a
b
c
d
f
g
h
e
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.
Freeze Protection: A sensor inside the boiler automatically
detects the temperature and, if necessary, initiates a safety
heating cycle to prevent internal equipment damage due to
freezing temperatures.
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.
Carbon Monoxide Protection: The boiler is designed to
maintain a safe air-to-gas ratio and combustion rate. This
function is continuously monitored by the boiler’s air ratio
control module.
Thermostat Control Failure: Should the thermostat fail to
function properly, the boiler’s gas supply will be shut off
automatically as a safeguard.
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. About the Boiler
