Navien NFC-175 Installation & Operation Manual page 48

CAUTION
Install a manual gas shut-off valve between the gas supply
●
line and the boiler.
A sediment trap must be provided upstream of the gas
●
controls.
Tighten the boiler connection valves with care to
Note
●
avoid damage.
The gas connection fitting on all boilers is
●
/ in rigid pipe can be used; refer to the sizing tables
1
●
2
on the proceeding pages for limitations. Do not use
/ in corrugated connectors or tubing as noise may
1
2
occur.
When using flexible gas lines, ensure that the pipe's
●
inner diameter and connector is sufficient to supply
the required BTUs. Also, ensure that the flexible line
has no crimps or tight bends in it, as this will restrict
gas flow.
When using rigid pipe, Navien recommends the
●
installation of a union on the gas supply line close
to the boiler, to facilitate any future maintenance or
service.
Check with the local jurisdiction to verify whether
●
the use of /
1
CAUTION
Prior to using an excess flow valve (EFV) in the gas line, check
the manufacturer's minimum and maximum flow capacity
rating. An improperly sized EFV will not allow for a full flow of
gas to the boiler and may cause improper operation.
CLOSE: 195
MAX OPER: 135
BYPASS: 5
48 Connecting the Gas Supply
Corrugated Connector
" gas pipe is approved in the area.
2
CLOSE: 195
MAX OPER: 135
BYPASS: 5
Excess Flow Valve
Typical LP Gas piping examples:
2 Stage System with Multiple Regulators (Recommended)
Gas Regulator (2 Stage)
High
Pressure
Regulator
/ in.
3
4
Gas Tank
Single Regulator System
Gas Tank
Low Pressure Regulator
(before entering home or building)
Full size
Gas Pipe
Gas Regulator
(12" WC)
Full size
Pipe
Gas Pipe
Full size
Gas Pipe