Navien NFB-175H, Руководство по установке, Страница: 49 / 135

49 Connecting the Gas Supply
Note
●
Tighten the boiler connection valves
with care to avoid damage.
●
The gas connection fitting on all
boilers is
3
/
4
in.
●
1
/
2
in rigid pipe can be used; refer to
the sizing tables on the proceeding
pages for limitations. Do not use
1
/
2
in
corrugated connectors or tubing as
noise may occur.
Corrugated Connector
●
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.
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 KBTU /HR
CLOSE: 195
MAX OPER: 135
BYPASS: 5
KBTU /HR
Excess Flow Valve
6. Connect the gas supply line.
7. Test the supply line, all connection points, and
the boiler for gas leaks.
Note
Tighten the boiler connection valves
with care to avoid damage.
Gas Inlet Adapter
Bottom View
Union
Gas Shut off
Valve
Gas Supply
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.