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SECTION 2
EDR-PURE-IOM-230608
FIGURE 9 MEASURING INLET GAS PRESSURE
ƒ Inlet Gas Pressure
Adhere to the following:
ƒ
Static inlet gas pressure: Measure while boiler is idle.
Verify pressure is within allowable range.
ƒ
Dynamic inlet gas pressure: Measure while boiler is in
operation at maximum ring rate. Verify pressure is
within allowable range.
ƒ
The gas delivery system must provide a stable and
consistent pressure across the entire turndown range,
including light o and idle conditions.
ƒ
Maximum inlet gas pressure drop from static to dynamic
must not exceed 15%, or the maximum allowable by
local code (CSA B149 clause 6.3.2 for Canada). The
stricter of the two shall apply.
ƒ Gas Pressure Requirements
The minimum gas pressure required is 4" W.C. For gas pressures
exceeding 28"W.C. (14"W.C. Canada), a step down regulator (not
supplied) must be installed in the gas supply piping.
Questions? Please Contact Your Local Manufacturer's Representative
ƒ Line Gas Pressure Regulation
When inlet gas pressure exceeds 28"W.C. (14"W.C. Canada), a
line gas pressure regulator is required to step the gas pressure
Measure
down below maximum pressure.
inlet supply
gas pressure
Proper selection and installation of a gas pressure regulator
here
is essential in providing conditions for e cient and reliable
combustion. Adhere to the following guidelines when
selecting and installing a gas pressure regulator:
ƒ A line pressure regulator listed and labeled to ANSI
Z21.80/CSA 6.22 is recommended. Lock-up is de ned
as an outlet pressure not more than 150% or 5"
W.C., whichever is greater, above the setpoint after
a downstream safety shuto valve closes within 2
seconds. Appliance regulators are not a substitution for
line gas pressure regulators and must not be used.
ƒ A gas pressure relief valve may be required for
overpressure protection, refer to the local code(s)
adopted by the AHJ.
ƒ A sediment trap is recommended prior to the inlet of
the regulator.
ƒ If the level of pipe system cleanliness is unacceptable
or unknown, it is recommended that a gas lter be
installed prior to the regulator.
ƒ On the outlet of the regulator: Install a straight and
uninterrupted section of pipe matching regulator
connection size with a minimum length of 10 pipe
diameters prior to any valves or ttings.
ƒ When installed in close proximity to an appliance,
some regulators may experience oscillation (hunting)
or an outlet pressure spike when demand ends.
Provide adequate volume by locating the regulator
a recommended minimum of 10 total linear feet of
pipe from boiler fuel train inlet. Consult the regulator
manufacturer for installation requirements.
ƒ The body size should never be larger than the pipe size.
However, a properly sized regulator may be smaller
than the pipe size.
ƒ The inlet pressure used for sizing should be measured
directly at the regulator inlet. Measurements taken at
any other point may be subject to losses associated
with upstream piping.
ƒ Consult the regulator manufacturer for ori ce selection.
ƒ If two or more springs are available for a particular
outlet pressure in the desired range use the spring with
the lower range for better accuracy.
INSTALLATION
2-13
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