System Details; Setting The Dip Switches; Pcb Dip Switches; Front Panel Dip Switches - Navien NCB-700-2S+/42K Service Manual

4. System Details

4.1 Setting the DIP Switches

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.
The boiler has 2 sets of DIP switches on the main circuit board
(PCB) and 2 sets of DIP switches on the front panel. DIP switches
are used to control the functionality of the boiler. Set the DIP
switches appropriately, based on the installation environment.

4.1.1 PCB DIP Switches

Dip Switch (Set of 8)
The DIP SW on the circuit board configures boiler type, capacity,
burner type, country, and discharge of condensate function.
[Example of DIP Switch On/Off]
DIP SW
Switch Function
1 Boiler Type
2 Reserve
3 & 4 Capacity
5 & 6 Country
7 & 8 Boiler Model
20 System Details
ON
1 2 3 4 5 6 7 8
ON
OFF
Setting
COMBI OFF
- -
42kW 3-OFF,4-ON
54kW 3-ON,4-ON
UK 5-OFF,6-OFF
NCB700 7-OFF,8-ON

4.1.2 Front Panel DIP Switches

Dip Switch (Set of 2)
The DIP SW on the front panel configures the fuel selection.
Switch Function
1 & 2 Fuel selection

4.2 Measuring the Incoming Gas Pressure

WARNING
The boiler cannot function properly without sufficient inlet
gas pressure. Measuring the inlet gas pressure should be
performed by a licensed professional only.
Natural Gas Connection
The gas supply must comply to the current Gas Safety
●
(Installation and Use) Regulations, in accordance with BS 6891.
The nominal inlet working gas pressure measured at the
●
appliance should be 21 mbar +/- 2 mbar for Natural gas (G20).
Allowing for the acceptable pressure loss of 1 mbar across
the installation pipework, it can be assumed that a minimum
permitted operating pressure of 18 mbar will be delivered
to the inlet of the appliance. (Reference BS 6400-1 Clause 6.2
Pressure Absorption).
When tested at the gas valve, the pressure drop from the
●
meter to the gas valve must not be more than 3 mbar.
1 2
O
N
Setting
LNG(G20) 1-OFF, 2-OFF
Not Used 1-OFF, 2-ON
LPG(G30) 1-ON, 2-OFF
LPG(G31) 1-ON, 2-ON