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Follow the installation instructions included with
the air removal device when placing it in the system;
air removal devices generally work better when
placed higher in the system. Always locate air
removal devices in areas of the system that have a
guaranteed positive pressure, e.g., in close proximity
to the water fill and expansion tank.
Connecting an air vent on top of the
Note
boiler is recommended.
Expansion Tank
The expansion tank must be sized in accordance
with the water volume of the system as well as the
firing rate of the appliance. It is important to locate
the expansion tank, and make-up water connection,
on the inlet side of any pump in the system, as
doing so will guarantee the lowest pressure in the
system will be at least equal to the tank and make-
up water pressure.
Ensure the expansion tank cannot become isolated
from the boiler anytime the system is operating.
Failure to follow these instructions may lead to
discharge from the pressure relief valve, which may
result in property damage or injury.
The installation of flow checks,
Note
motorized valves or other shutoff
devices (other than for the purpose of
servicing) are not permitted between the
location of the "Closely Spaced Tees" and
the expansion tank.
Air Handler Interface
The Navien NHB-H boiler can control the operation
of an air handler when a thermostat is used in
combination with the air handling unit. The Air
Handler Interface is designed to stop air handler
operation when the boiler's space heating function
is not operating due to DHW supply demands, boiler
errors, or low water conditions.
The air handler contacts (A/H) turn off when the
following conditions arise:
The PCB DIP SW2 (Set of 8 Switches) #7 is set to
●
ON.
Thermostat is turned off.
●
The boiler is supplying DHW, or it is in stand-by
●
mode for DHW demand.
Level 2 or higher errors occur.
●
The boiler is turned off.
●
28
Installing the System Piping
CAUTION
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.
Configure only the DIP switches that require
●
adjustment according to the instructions
in this manual. Do not adjust any other DIP
switches.
Thermostat Configuration for the Air
Handler Interface
Set the PCB DIP SW2 (Set of 8 Switches) #7 to down
position (OFF) to use a thermostat with the Air
Handler.
O
O
N
N
1
2
3
4
5
6
Refer to the "3.6.9 Wiring Diagram - Air Handler" on
page 43 for wiring connections.
1
2
3
4
5
6
7
8
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