ASME CSD-1:2006 pdf free download.Controls and Safety Devices for Automatically Fired Boilers.
prepu rye period: a period of time on each startup during which air is introduced into the combustion chamber and associated flue passages in volume and manner as to completely replace the air or fuel-air mixture contained therein prior to initiating ignition.
pressure regulator, LP-gns,first stage: on undiluted LP-gas systems, a pressure regulator designed to reduce pressure from the container to 10.0 psi (69 kPa) or less.
pressure regulator, LP-gas, second lage: a pressure regulator for service on undiluted LI’-gas systems designed to reduce first stage regulator outlet pressure to 14.0 in. W.C. (4.0 kPa) or less.
pressure regulator, service: a pressure regulator installed by the serving gas supplier to reduce and limit the service line gas pressure to delivery pressure.
proren prepurge: a provision of the control system for preventing burner operation until prescribed air flow is proven to be established during prepurgc.
qualted individual: a boiler service technician who is engaged in and is responsible for installation, replacement, repair, or service of the boiler, fuel burning system controls, and safety devices and is experienced in such work.
readily accessible: having direct unimpeded access without the need of a ladder or removing or moving any panel, door, or similar covering of the item described. recycle: the process of sequencing a normal burner start following safety shutdown before the establishment of lockout.
relay: a device that is operative by a variation in the conditions of one electric circuit to start the operation of other devices in the same or another electric circuit, such as pressure or temperature relay.
relight: the action upon loss of main flame to reestablish the ignition source without recycle.
sediment trap: a device in a gas line that collects and prevents solid debris (such as pipe dope, slag, dirt, etc.) from traveling downstream into the gas controls. (See Fig. 1.)
shutdown, normal: shutting off fuel and ignition energy to the burner by means of an operating control.
shutdown, safety: shutting off all fuel and ignition energy to the burner by means of a safety control or a primary safety control (see also lockout).
switch, airflow: a device used to prove the flow of air. switch, high oil temperature: a temperature-actuated device arranged to stop the flow of fuel to a preheated
(b) The electrical circuit shall be connected in such a manner that either low-water fuel cutoff control will shut off the fuel or energy supply to the boiler when a low-water condition develops. One cutoff control shall be set to function ahead of the other.
(1) With a pumped condensate return, functioning of the lower of the two cutoff controls shall cause safety shutdown and kkout. The manual reset may he incorporated in the lower cutoff control. Where a reset device is separate from the low-water fuel cutoff, a means shall be provided to indicate actuation of the low-water fuel cutoff. The manual reset device may he the instantaneous type, or may include a time delay of not more than 3 mm after the fuel has been cut off.
(2) With gravity condensate return, the lower of the two cutoff controls shall be electrically connected with the upper cutoff to cause a safety shutdown requiring manual reset only when the upper cutoff has failed to function.
(c) The fuel cutoff device may be inserted internally or attached externally to the boiler, An external cutoff device may be attached to piping connecting a water column to the boiler or combined with a water column. Water column piping and connections shall be at least NPS 1. If the lower water fuel cutoff is connected to the boiler by pipe or fittings, no shutoff valves of any type shall be placed in such piping. A cross, or equivalent fitting, shall be placed in the water piping connection at every right angle to facilitate cleaning and inspection. Fuel cutoff devices embodying a separate chamber shall have a vertical drainpipe and a blowoff valve, not less than NI’S , located at the lowest point of the chamber or water-equalizing pipe connections so that the chamber and the equalizing pipe can be flushed and the device tested.
