Gas Piping - CleaverBrooks CFC-500 Operation, Service And Parts Manual

Section 2 — Installation
Pressure
Test
Figure 2-22 Test cocks - gas
valve
2-16

4. Gas Piping

CFC units are not standardly equipped with an upstream gas
Leak Test
pressure regulator. Therefore, a regulator must be installed at each
CFC unit. Do not use a common regulator to regulate pressure for a
multiple unit installation. Note: Gas connection is at the rear of the
boiler, left hand side as you face the rear of the boiler.
If local code permits, a flexible connection can be used between the
gas line and gas valve. This will enable the burner door to be opened
without disconnecting the gas line.
Leak Test
The regulator for each boiler must be installed with at least 2 feet of
pipe between the regulator and the boiler gas train connection. The
discharge range of the regulator must be able to maintain gas
pressures as noted in Table 2-3.
For buildings or boiler rooms with gas supply pressure exceeding 28"
w.c. a "full lock-up" type regulator is required as well as overpressure
protection (e.g. relief valve).
In addition to the regulator, a plug type or "butterball" type gas
shutoff valve must be installed upstream of the regulator for use as a
service valve. This is also required to provide positive shutoff and
isolate the unit during gas piping tests.
If necessary a strainer should be installed upstream of the regulator
to remove debris from the gas supply.
Drip legs are required on any vertical piping at the gas supply to
each boiler so that any dirt, weld slag, or debris can deposit in the
drip leg rather than into the boiler gas train. The bottom of the drip
leg should removable without disassembling any gas piping. The
connected piping to the boiler should be supported from pipe
supports and not supported by the boiler gas train or the bottom of
the drip leg. Do not pipe across the top of the boiler as the burner
swings up for service and must have proper clearance.
All gas piping and components to the boiler gas train connection
must comply with NFPA 54, local codes, and utility requirements as
a minimum. Only gas approved fittings, valves, or pipe should be
used. Standard industry practice for gas piping is normally Schedule
40 black iron pipe and fittings.
Before starting the unit(s) all piping must be cleaned of all debris to
prevent its entrance into the boiler gas train. Piping should be tested
as noted in NFPA 54 and the boiler must be isolated during any
tests.
After initial startup, the inlet screen to the gas valve should be
checked and cleaned of any debris buildup.
See Figure 2-23 for a typical piping configuration.
Part No. 750-263