Startup from Cold of a Boiler,The following procedures should be followed when starting a fossilfuel boiler from cold condition

Startup from Cold

The following procedures should be followed when starting a fossilfuel

boiler from cold condition:-

(a) Read and be fully conversant with the detailed operating

instruction for the boiler and its auxiliaries.

( b) Check the Certificate of Fitness (CF) for the boiler to ensure

that it has not expired and that the approved maximum

permissible working pressure (MPWP) is indicated on the

pressure gauge by a red line.

(c) Shut the steam outlet stop valve and the blowdown/drain

valve.

(d) Open the air vent.

(e) Set the water level gauge valves/cocks to the normal operating

positions (see Appendix III for reference).

(f) Feed water into the boiler as appropriate until the water level

is just below the half-gauge level.

(g) Check that the fuel supply is securely connected and there is

no visual loose connection or fuel leakage.

(h) Set the heating at low firing rate.

(i) Switch on the blower to purge the furnace for the period

recommended by the maker or for at least 15 minutes. The

operator should observe the uptake flap to ensure that a

draught for purging, has been established in the furnace. If

such flap is not provided, the operator should make use of the

particular boiler design to ensure that draught has been

e s t a b l i s h e d .

(j) Switch on the oil fuel pump or the main gas supply and see

that fuel pressure is built up and the oil fuel is circulating (no

circulation is necessary for gas fuel). Confirm that there is no

fuel leakage. If there is any leakage, shut down the boiler and

arrange the repair before proceeding.

(k) Now the boiler ignition system may be switched to establish a

flame inside the furnace, for raising steam at a low firing rate.

The operator may choose to a use continuous firing method or

intermittent firing method depending on the design and the

past operating experience of the boiler. Intermittent firing is

safer but takes a longer time to raise steam. In many practices,

intermittent firing is typically 10 minutes fire in every 20

minutes, until steam is generated.

(l) If the ignition fails, repeat from step (i). However, if it fails to

ignite for several times, stop the fuel supply and purge the

furnace for the period recommended by the maker or for at

least 10 minutes. Examine the burner, the flame detector and

the fuel system such as fuel quality (e.g. is there water

contamination in the oil fuel). When everything is found in

o r d e r, repeat from step (i).

(m) The boiler should be heated gradually to raise steam. After

steam has been coming out from the air vent for 3-5 minutes,

shut the air vent. This waiting period is to ensure that all air

trapped inside the boiler has been driven out.

(n) The boiler may now be switched to high firing rate to bring the

steam pressure to the working pressure which shall be less

than the MPWP.

(o) Blow the water level gauge (see Appendix III for blowing

procedures) to see that the gauge is in proper working order.

(p) When the steam pressure has reached the working pressure,

open the steam outlet stop valve gradually and cautiously. If

hammering or any abnormal noise is heard along the steam

pipeline, do not open the stop valve any further. Instead, the

stop valve should be closed to a 'cracked open' position (about

1/2 turn open) to warm the pipeline. If possible, the pipeline

should be drained during this procedure. After warming the

pipeline for a few minutes, the stop valve can be opened

gradually and cautiously again until fully opened.

(q) The steam outlet stop valve should be fully open at all times

during operation. Do not throttle the stop valve.

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M❤K