1.5 Gas Connection and Supply
The gas connection to the heater is ½” N.P.T
internal thread.
Injector sizes and manifold pressure for the
burners are shown in Section 1.9. The gas
supply piping and connections must be installed
so that the recommended pressure stated is
achieved.
A gas shut off valve and union should be fitted
in the gas supply line close to the heater and a
⅛
” N.P.T plugged tapping, accessible for test
gauge connection, provided immediately
upstream of the appliance gas inlet.
It is essential to provide some flexibility in the
final gas connection by use of an approved
flexible gas connector. See Fig 4.
Take care when making a gas connection
to the heater not to apply excessive turning
force to the internal controls.
Care must be taken to observe the minimum
pipe bend diameter (minimum 10” - 250mm,
maximum 14” - 350mm) & pipe expansion
distance (minimum 1
⅛
” - 28mm, maximum
3¾”) - 95mm.
The correct installation as shown will allow
for approx 4” of movement due to
expansion.
WARNING:
Before installation, check
that the local distribution conditions,
nature of gas and pressure, and adjustment
of the appliance are compatible.
Figure 3. Correct orientation of Ball Valve
Gas Flow
Gas Flow
Figure 4. Correct Installation of Flexible
Gas Connection
8
WARNING:
FIRE OR EXPLOSION HAZARD - Expansion of the radiant pipe occurs with
each firing cycle causing the burner to move with respect to the gas line. This can
result in a gas leak producing an unsafe condition. It is therefore essential to provide some
flexibility in the final gas line connection by use of an approved armoured flexible
connector or stainless steel expansion loop as shown in the drawings.