Natural Gas Measurement, Control, and Odorization Log
We provide insights into natural gas measurement, control, odorization, and various natural gas products.
Maxitrol Regulator - Gas Line Pressure versus Appliance Control
Are you confused by line pressure and appliance regulator standards? Can an appliance model serve as a line pressure regulator? Alternatively, can a line pressure unit serve as an appliance regulator? Get Maxitrol answers.
Recently, it became clear that a customer was using an appliance regulator as a line pressure regulator and they were not conforming to standards. Here is the reader's digest version of the rules and how they apply to Maxitrol units.
The current standards for appliance regulators are ANSI Z21.18/CSA 6.3 while line pressure regulator standards are ANSI Z21.80/CSA 6.22. Historically, appliance regulators were used as line pressure regulators before ANSI Z21.80/CSA 6.22 was developed. With the implementation of the newer and revised standards, appliance regulators should no longer be used as line pressure regulators. This rule has been confusing given that many longtime favorite appliance regulators installing as line pressure regulators.
The standards apply to natural gas, manufactured and mixed gases, liquefied petroleum gases, and LP gas-air mixture systems.
Maxitrol Appliance Regulators
The Maxitrol RV Poppet Series, RV Straight-Thru-Flow Series, and RS Balanced Valve Series are certified ANSI Z21.18 as appliance regulators and rated for a maximum inlet pressure of ½ PSI with outlet pressures being 2.8" or 3" to 12" WC.
Maxitrol's 325 Series regulators (325-3, 325-5, 325-7A and 325-9) are also certified ANSI Z21.18/CSA 6.3 as appliance regulators for main burner or pilot applications with a maximum inlet pressure of 5 PSI (CSA certified).
The same Maxitrol 325 Series has an "L" line, denoting that the "L" regulators are certified as line pressure regulators able to supply gas pressure to one or more appliances downstream.
Line Pressure Regulators
We use line pressure regulators in a building's gas distribution system and install them between the service regulator and the gas appliance's pressure regulator.
Maxitrol's 325-L Series line pressure regulators are certified ANSI Z21.80/CSA 6.22 in 2 PSI and 5 PSI systems [when installing with an overpressure protection device (OPD)]. The L-Series regs are used in CSST (corrugated SS), semirigid copper pipe, or steel/black iron pipe. The regulators reduce the pressure to a level within the appliances operating supply range. Install the line pressure regulator upstream of devices already fitted with an appliance regulator.
2 PSI PIPING SYSTEMS
The Maxitrol 325 L-Series line pressure regulators are certified for 2 PSI inlet pressure, with outlet pressures ranging 7 to 11 inches WC. The 325-L Series regulators in 2 PSI systems deliver positive dead-end lockup capable of precise control from full flow down to pilot flow; suggesting that one 325-L would suffice as both line pressure and appliance regulator.
UP TO 5 PSI PIPING SYSTEMS
At supply pressures above 2 PSI, the ANSI Z21.80/CSA 6.22 standard requires an overpressure protection device that is factory assembled, approved and tested for use with the regulator, to limit the downstream pressure to 2 PSI maximum, in the event of line regulator failure.
The Maxitrol 325 L-Series with an overpressure protection device (OPDs) is certified for up to 5 PSI inlet pressure and outlet pressures ranging 7 to 11 inches WC.
In a 5 PSI system, a second appliance (RV Series or 210 with vLimiter) in series with the 325-L regulator (with OPD) would be needed. The following factory-assembled 325-L line regulator with OPD will work:
|Line Size||Maxitrol 325-L||Description|
|½"||325-3L48||Line Regulator with OPD|
|¾" or 1"||325-5L600||Line Regulator with OPD|
|1-1/4" or 1-1/2"||325-7AL210D||Line Regulator with OPD|
|1-1/2" or 2"||325-9L210E||Line Regulator with OPD|
Options for Line Pressure Control
Vent Limiting Device
The vLimiter is a vent limiting device that eliminates the need to vent to an exterior wall. When using the vLimiter, the regulator must be installed in a horizontal upright position, and if there is a diaphragm rupture, the gas escapement is within ANSI standard requirements.
The vProtector is for outdoor applications of Maxitrol units. Install the vent protector on the vent opening to protect the breather hole from the elements and debris.
If you are interested in Maxitrol, submit your inquiry to the request for information or call us at (303) 697-6701.