Part 7 - Gas Connections; Gas Piping - Westinghouse WBMC**500 Manual

Part 7 - Gas Connections

Failure to follow all precautions could result in fire, explosion,
severe injury, or death.
It is very important that you are connected to the type of
gas noted on the rating plate. "LP" for liquefied petroleum,
propane gas, or "NG" for natural or city gas. Do not do a gas
conversion without an approved gas conversion kit. Prior to
turning the gas on, all gas connections must be approved by
the local gas supplier or utility, in addition to the governing
authority.
A gas conversion kit comes with 500 boilers ONLY. Field
conversions ARE NOT ALLOWED on the 850. A properly
calibrated combustion analyzer must be used to verify proper
combustion. Failure to follow the above instructions could
result in property damage, serious injury, or death.
The gas supply shall have a maximum inlet pressure of less
than 14" w.c. (3.5 kPa), and a minimum of 3.5" w.c. (.87 kPa).
The entire piping system, gas meter and regulator must be
sized properly to prevent pressure drop greater than 0.5" (.12
kPa) as stated in the National Fuel Gas Code. This information
is listed on the rating label.
UL recognized fuel gas detectors are recommended in
all enclosed propane and natural gas applications where
there is a potential for an explosive mixture of fuel gas to
accumulate. The installation of these detectors should
be made in accordance with the detector manufacturer's
recommendations, and/or local laws. Failure to install fuel gas
detectors in these applications could result in fire, explosion,
property damage, severe personal injury, or death.
The gas connection on the boiler is 1 1/2" for the 500 and 2" for
the 850. It is mandatory that this fitting is used for connection
to a field fabricated drip leg as shown in the illustration per the
National Fuel Gas Code. You must ensure that the entire gas
line to the connection at the boiler is no smaller than the unit
supplied connection.
Once all inspections have been performed, the piping must
be leak tested. If the leak test requirement is a higher test
pressure than the maximum inlet pressure, you must isolate
the boiler from the gas line. In order to do this, shut the gas off
using factory and field-installed gas cocks. This will prevent
high pressure. Failure to do so may damage the gas valve. In
the event the gas valve is exposed to a pressure greater than
½ PSI, 14" w.c. (3.5 kPa), the gas valve must be replaced.
Never use an open flame (match, lighter, etc.) to check gas
connections.
A. Gas Piping
1. Run the gas supply line in accordance with all applicable
codes.
2. Locate and install manual shutoff valves in accordance with
state and local requirements.
3. In Canada, the Manual Shutoff must be identified by the
installing contractor.
4. It is important to support gas piping as the unit is not
designed to structurally support a large amount of weight.
5. Purge all gas lines thoroughly to avoid start up issues with air
in the lines.
6. Sealing compound must be approved for gas connections.
Care must be taken when applying compound to prevent
blockage or obstruction of gas flow which may affect the
operation of the unit.
Support gas supply piping with hangers, not by the boiler or its
accessories. The boiler gas valve and blower will not support the
weight of the piping. Make sure the gas piping is protected from
physical damage and freezing, where required. Failure to follow
these instructions could result in gas leakage, and result in fire,
explosion, property damage, severe personal injury, or death.
Do not use Teflon tape on gas line pipe thread. Use a pipe
compound rated for use with natural and propane gases. Apply
sparingly on male pipe ends, leaving the two end threads bare
and flow unobstructed. Failure to follow these instructions could
result in gas leakage or blockage, and result in fire, explosion,
property damage, severe personal injury, or death.
Figure 28 - Gas Connection
37
WHL-033 Rev. 1.29.16