F5 commision boilers Flashcards
(39 cards)
What is the standard practice regarding hydrostatic testing of a boiler after transport and installation?
After transport and installation, the boiler is hydrostatic tested again before it is put into service, even though each boiler is pressure tested at the manufacturer.
Why is it important not to pressure test against instrumentation like pressuretrols, aquastats, transducers, and safety valves?
A general rule is to NOT pressure test against instrumentation. These components should be disconnected and their tapings plugged to avoid damage.
What measures should be taken on higher pressure boilers to prevent crushing the copper float during a hydrostatic test?
Remove the low water cut-off head and install a blind.
What is the general guideline for increasing and holding pressure within a boiler during a hydrostatic test, and for how long should it be held?
The pressure should be slowly brought up to 1.5 times the maximum allowable working pressure (MAWP) of the boiler and held for a minimum of 30 minutes.
Who typically performs and witnesses a hydrotest, and what needs to be recorded?
A hydrotest should be performed and witnessed by an authorized individual, and documented in the commissioning report.
What ‘paperwork’ should be in order before beginning the commissioning of an appliance?
The necessary permits and documentation should be in order.
Under what conditions is a commissioning approval inspection required according to section 26 (2) of the GSR?
A commissioning approval inspection is required for a new appliance or when an existing appliance has been modified, altered, or reinstalled, and the heat input exceeds 409,600 BTUs per hour (120 kW).
Why is it crucial to obtain permission from the Gas Safety Officer before firing the burner during commissioning?
Failure to obtain permission could result in fines.
Before initial firing, what must be done with the bolts securing the ‘floating end’ of a firetube boiler to the skid, and why?
The bolts are tightened for shipment so the boiler does not move on the skid. Prior to initial firing, the bolts securing the “floating end” to the skid must be loosened to allow for expansion and contraction.
What is the expectation regarding boiler insulation and gasket sealing after shipping and installation but before putting it into service?
All insulation should be properly fitted and all gaskets sealing the various parts should be installed.
What visual inspection should be performed on the refractory after shipping?
The refractory should be visually inspected for any damage.
What checks are essential for wiring and motor rotation before starting the boiler?
All wiring should be checked for correctness and tightness. Motor rotation for fans and pumps should be verified for proper direction.
Why is it critical to ensure discharge piping from safety valves, relief valves, blowdown, and drain valves is piped to a safe point of discharge prior to firing a boiler?
To prevent scalding or other hazards.
How should a boiler be filled prior to start-up, and what type of water should be used?
The boiler should be filled slowly with treated water (if applicable) through the fill connection.
What is the procedure for venting air on a steam boiler during filling and operation?
The boiler should be filled with water to the normal operating level, and air should be vented from the boiler through the appropriate vent valve.
What needs to be confirmed regarding the LWCO pump control and water levels on a steam boiler?
The LWCO pump control is working correctly and maintaining proper water levels.
What reference point should be used for the water level when using the sight glass on the LWCO?
The normal operating water level should be the center line of the glass.
What measurements should be recorded in the commissioning report concerning the operational points of the low water cut-off?
Record the water levels at which the LWCO and AuxLWCO activate, including the cut-out point.
Describe the function of an Operating Limit Control.
An Operating Limit Control cycles the burner on and off to maintain the desired pressure or temperature.
When setting controls, why must consideration be given to the time required for a burner restart?
It affects the boiler’s ability to maintain stable pressure or temperature.
How should the ‘cut-out’ (burner off) pressure be set on the operating pressure control of a steam boiler in relation to the safety valve setting?
at least 10% lower
than the setting of the safety valve.
What is the function of a High Limit Control, and why should it be set sufficiently above the operating limit control?
A High Limit Control shuts down the burner if pressure or temperature exceeds a predetermined safe limit, providing a safety margin.On a high pressure steam boiler, if feasible the high limit control should be set approximately 10 psig above the operating limit pressure control, or midway between the operating limit
pressure and safety valve setting. On a hot water boiler, the high limit
temperature control should be 5℉ 𝑡𝑡𝑡𝑡 10℉ above operating limit temperature control setting. The setting should be sufficiently above the operating limit temperature to avoid unnecessary shutdowns. On a 30 psig hot water boiler, the setting is
not to exceed 240℉.
Explain the manual reset feature of a high limit control and the steps required to reset it.
Once the control trips, it must be manually reset by an operator, typically by pressing a reset button after correcting the trip condition.
Why is heat curing essential for new refractory installations, and how is it typically accomplished?
Heat curing removes moisture and properly sets the material, typically accomplished by firing the boiler at specific low temperatures.
