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SECTION 2
EXE-IOM-230112
Measure at the location shown in Figure 8 and adhere to the following:
Static inlet gas pressure: Measure while boiler is idle. Verify pressure is
ƒ
within allowable range.
Dynamic inlet gas pressure: Measure while boiler is in operation at
ƒ
maximum firing rate. Verify pressure is within allowable range.
The gas delivery system must provide a stable and consistent pressure
ƒ
across the entire turndown range, including light off and idle conditions.
Maximum inlet gas pressure drop from static to dynamic must not exceed
ƒ
15%, or the maximum allowable by local code (CSA B149 clause 6.3.2 for
Canada). The stricter of the two shall apply.
ƒ Line Gas Pressure Regulation
When inlet gas pressure exceeds 14"W.C. a line gas regulator (not provided)
listed and labeled to ANSI Z21.80/CSA 6.22 will be used to step the gas pressure
down below the boiler's maximum gas pressure.
Proper selection and installation of a gas pressure regulator is essential in
providing conditions for efficient and reliable combustion. Adhere to the
following guidelines when selecting and installing a gas pressure regulator:
A line pressure regulator listed and labeled to ANSI Z21.80/CSA 6.22
ƒ
is recommended. Lock-up is defined as an outlet pressure not more
than 150% or 5" W.C., whichever is greater, above the setpoint after a
downstream safety shutoff valve closes within 2 seconds. Appliance
regulators are not a substitution for line gas pressure regulators and must
not be used.
A gas pressure relief valve may be required for overpressure protection,
ƒ
refer to the local code(s) adopted by the AHJ.
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
ƒ
recommended that a gas filter be installed prior to the regulator.
On the outlet of the regulator: Install a straight and uninterrupted section
ƒ
of pipe matching regulator connection size with a minimum length of 10
pipe diameters prior to any valves or fittings.
When installed in close proximity to an appliance, some regulators may
ƒ
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.
The body size should never be larger than the pipe size. However, a
ƒ
properly sized regulator may be smaller than the pipe size.
The inlet pressure used for sizing should be measured directly at the
ƒ
regulator inlet. Measurements taken at any other point may be subject to
losses associated with upstream piping.
Questions? Please Contact Your Local Manufacturer's Representative
INSTALLATION
2-13
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