CSA 4.9-2014 Gas-fired low pressure steam and hot water boilers.
Listed — equipment or materials included in a list published by a nationally recognized testing laboratory, inspection agency, or other organization concerned with product evaluation that maintains periodic inspection of production of listed equipment or materials, and whose listing states either that the equipment or material meets nationally recognized standards or has been tested and found suitable for use in a specified manner.
Lockout — the automatic action to end an ignition sequence.
Hard lockout — reinitiating another ignition sequence requires a manual operation at the appliance or interruption of the main electrical power supply to the appliance.
Soft lockout — reinitiating another ignition sequence is accomplished by manual or automatic means which may be remote from the appliance.
Lockout time — the period of time between energizing the system and lockout if proof of the supervised ignition source or the supervised main burner is not established.
Low water cutoff — a device constructed so as to automatically cut off the fuel supply when the surface of the water in a boiler falls to the lowest safe water level. This point should not be lower than the bottom of the water-glass.
LP gas-air mixture — liquefied petroleum gases distributed at relatively low pressures and normal atmospheric temperatures which have been diluted with air to produce desired heating value and utilization characteristics.
Main burner — a device or group of devices essentially forming an integral unit for the final conveyance of gas or a mixture of gas and air to the combustion zone, and on which combustion takes place to accomplish the function for which the appliance is designed.
Manifold — the conduit of an appliance which supplies gas to the individual burner.
Manual burner test firing valve — a manually operated lubricated plug-type variable position valve which is usually operated with an attached handle or, in the larger sizes, by a loose fitting or extended wrench downstream of all other valves on the valve train.
Manual pilot shutoff valve — a manually operated valve in the gas line for the purpose of completely turning on or shutting off the gas supply to the pilot(s).
Maximum regulation capacity — the high limit of flow below which is found acceptable regulating c ha ra cte risti Cs.
Mixer — the combination of mixer head, mixer throat and mixer tube.
Mixer head — the portion of an injection (Bunsen) type burner, usually enlarged, into which primary air flows to mix with the gas stream.
Mixer throat — the portion of the mixer which has the smallest cross-sectional area and which lies between the mixer head and the mixer tube.
Mixer tube — the portion of the mixer which lies between the throat and the burner head.CSA 4.9 pdf download.