P99 LOW PRESSURE BOILER EXAM REVIEWED QUESTIONS
AND COMPLETE CORRECT ANSWERS
How do you determine if a boiler has sufficient safety valve capacity - answer-The accumulation test
determines if the valve will discharge all the steam pressure, without allowing the pressure to rise more
than 6% more than valve setpoint
If a safety valve opens at 100 psi, what pressure should it close at? What requirements governors safety
valve blowdowns? - answer-A: 96-98 psi, with no chatter, with a blowdown of no more than 4 psi of set
pressure.
A safety valve is limited to how many square ft of heating surface. - answer-Any boiler with more than
500 sq ft must have two or more safety valves
What is a safety valve and how does it operate - answer-Is a device that expels all excess steam pressure
from a boiler. The huddling chamber causes the valve to open fully causing a definite drop in pressure
before closing.
What type of stays are used in a the heads of a water tube boiler - answer-No stays, the head of the
boiler drum is shaped with a die, which would form them in the shape they would take when pressure is
applied.
Your fuel oil tank capacity is 20,000 and you have 10,000 left. How much do you order? - answer-8,000
gallons. Fuel tanks cannot be filled past 90% because of overfill protection.
Why are handhelds and manholes made oval instead of round. What are minimum sizes for both
openings? - answer-So they can be removed and inserted from respective openings in the boiler.
Manhole 11X5 or 10 X 16 handheld 2 3/4 X 3 1/2
What is thermal efficiency? What is a good percentage? - answer-It is the ratio of heat supplied by the
fuel to the heat absorbed by the boiler. 85%
, P99 LOW PRESSURE BOILER EXAM REVIEWED QUESTIONS
AND COMPLETE CORRECT ANSWERS
How do you determine boiler capacity and what is boiler heating surface - answer-Total heating surface
determines the capacity of the boiler. Heating surface on one side and boiler water on the other.
Measures from the fire side.
The oil is heated between - answer-160 and 180 Fahrenheit
The normal normal oil pressure for no. 6 oil burner is - answer-Between 30 and 50 psi
A back pressure relief valve is provided for safety if the - answer-Pressure becomes too great
Carbon and hydrogen are - answer-Two principal elements of fuel oil
Oil is a liquid fuel and as such - answer-Will not burn
A red smoky flame is an indication of - answer-A lack of air
The manual reset pressuretrol is a control that will shut down the a steam burner boiler if the - answer-
Pressure continues to rise above the operating control settings
The safety or pop off valve is a device used to - answer-Relieve excessive steam pressure
The boiler steam pressure gauge shows the steam pressure - answer-Inside the steam boiler
The stack switch is the - answer-Primary control
The aquastat - answer-Operates the oil burner for domestic hot water needs
The photoelectric cell is a - answer-Flame detection control
, P99 LOW PRESSURE BOILER EXAM REVIEWED QUESTIONS
AND COMPLETE CORRECT ANSWERS
The vaporstat is - answer-A low pressure; pressure control mounted on the fan housing and will shut
down the burner if no air for combustion exists
The main fuel valve - answer-A valve that will open or close the line leading to the automizer of the fuel
burner
The oil preheater - answer-Raises the temperature of the oil for easier pumping and atomization
What is the furnace volume? Is furnace volume measured in? - answer-Furnace volume is the space
available for complete combustion of the fuel before the products of combustion enter he heating
absorbing section of the boiler. This varies with the type of fuel used. Measure in cubic ft
How is a blowdown tank piped, how does it work and why isn't any pipe directly connected to sewer -
answer-The blowdown enters in the tank above the waterline, maintained in the tank against a splash
guard. There is a vent on the top of the tank to prevent back pressure. The tank tank dischArge line is
also vented to prevent siphoning. The tank has a drain valve and a manhole for cleaning. The discharge
line is opposite the inlet, resulting in the cooler water being discharged first. Flash steam and or hot
water directly into the sewer may injure people or damage sewer line.
What is a plug valve. And why is it used on blow down lines. - answer-A plug valve has a circular tapered
plug ground to fit into there valve body. There is a hole through the plug that aligns with the valve body
when open. When turned closed the holes are misaligned. The shearing action cuts thru scale and will
not fall open.
What is a slow opening valve - answer-It is a screw type that requires at least five full turns from closed
to open.
Where is the bottom blowdown pipe connected to an HRT boiler? What type valves are used on the
bottom blowdown and in what order are they placed? How should you blowdown a boiler using those
valves? What size blowdown pipe? - answer-Underside of the shell, at the rear of the boiler
Two slow opening, or one quick and one slow opening valve
Quick valve is installed next to the boiler, opened first closed last.
Size 1 inch, not greater than 2 1/2. 3/4 is allowed on boiler less than 100sq ft
, P99 LOW PRESSURE BOILER EXAM REVIEWED QUESTIONS
AND COMPLETE CORRECT ANSWERS
When is the best time to blowdown a boiler, what important safety procedure do you observe - answer-
During light loads, sludge has settled to bottom.
Blowdown 10 seconds,
Once you open the valve do not take your hand off until valve is closed
How should a continuous blowdown be piped as it leaves the boiler and why? - answer-It will be piped
through a heats exchanger or flash tank to recover the heat. Then onto the blowdown tank
What is a continuous blowdown system and where is it installed - answer-Based on water analysis the
surface blowdown is monitored for continuous flow. The take off is located just below the NOWL in the
steam and water drum
What is a surface blow off? Where is it employed and why used - answer-Remove oil continents form
the surface of boiler water. The take off is located in the top 3" or 4" of water it controls the TDS total
dissolved solids.
On a Ashton type safety valve the label "O" and "S", what stand for and what adjustments can be made -
answer-Open And shut. Not certified to make adjustments
A boiler designed to operate at 125psi, know operates at 15 psi. What changes need to be made.? -
answer-Permanent change, safety valve larger disk and lower pressure rating with need to be installed
How do you determine if a boiler has sufficient safety valve capacity - answer-Accumulation test will
determine if the boiler discharges pressure, not allow pressure to build over 6% if MAWP
How must a safety valve be connected to a boiler - answer-1. Independent of any other steam
connection
2. Close as possible without any other piping
3. Screwed into the boiler shell or fastened to a flange welded to the shell
4. Connected to stand upright
AND COMPLETE CORRECT ANSWERS
How do you determine if a boiler has sufficient safety valve capacity - answer-The accumulation test
determines if the valve will discharge all the steam pressure, without allowing the pressure to rise more
than 6% more than valve setpoint
If a safety valve opens at 100 psi, what pressure should it close at? What requirements governors safety
valve blowdowns? - answer-A: 96-98 psi, with no chatter, with a blowdown of no more than 4 psi of set
pressure.
A safety valve is limited to how many square ft of heating surface. - answer-Any boiler with more than
500 sq ft must have two or more safety valves
What is a safety valve and how does it operate - answer-Is a device that expels all excess steam pressure
from a boiler. The huddling chamber causes the valve to open fully causing a definite drop in pressure
before closing.
What type of stays are used in a the heads of a water tube boiler - answer-No stays, the head of the
boiler drum is shaped with a die, which would form them in the shape they would take when pressure is
applied.
Your fuel oil tank capacity is 20,000 and you have 10,000 left. How much do you order? - answer-8,000
gallons. Fuel tanks cannot be filled past 90% because of overfill protection.
Why are handhelds and manholes made oval instead of round. What are minimum sizes for both
openings? - answer-So they can be removed and inserted from respective openings in the boiler.
Manhole 11X5 or 10 X 16 handheld 2 3/4 X 3 1/2
What is thermal efficiency? What is a good percentage? - answer-It is the ratio of heat supplied by the
fuel to the heat absorbed by the boiler. 85%
, P99 LOW PRESSURE BOILER EXAM REVIEWED QUESTIONS
AND COMPLETE CORRECT ANSWERS
How do you determine boiler capacity and what is boiler heating surface - answer-Total heating surface
determines the capacity of the boiler. Heating surface on one side and boiler water on the other.
Measures from the fire side.
The oil is heated between - answer-160 and 180 Fahrenheit
The normal normal oil pressure for no. 6 oil burner is - answer-Between 30 and 50 psi
A back pressure relief valve is provided for safety if the - answer-Pressure becomes too great
Carbon and hydrogen are - answer-Two principal elements of fuel oil
Oil is a liquid fuel and as such - answer-Will not burn
A red smoky flame is an indication of - answer-A lack of air
The manual reset pressuretrol is a control that will shut down the a steam burner boiler if the - answer-
Pressure continues to rise above the operating control settings
The safety or pop off valve is a device used to - answer-Relieve excessive steam pressure
The boiler steam pressure gauge shows the steam pressure - answer-Inside the steam boiler
The stack switch is the - answer-Primary control
The aquastat - answer-Operates the oil burner for domestic hot water needs
The photoelectric cell is a - answer-Flame detection control
, P99 LOW PRESSURE BOILER EXAM REVIEWED QUESTIONS
AND COMPLETE CORRECT ANSWERS
The vaporstat is - answer-A low pressure; pressure control mounted on the fan housing and will shut
down the burner if no air for combustion exists
The main fuel valve - answer-A valve that will open or close the line leading to the automizer of the fuel
burner
The oil preheater - answer-Raises the temperature of the oil for easier pumping and atomization
What is the furnace volume? Is furnace volume measured in? - answer-Furnace volume is the space
available for complete combustion of the fuel before the products of combustion enter he heating
absorbing section of the boiler. This varies with the type of fuel used. Measure in cubic ft
How is a blowdown tank piped, how does it work and why isn't any pipe directly connected to sewer -
answer-The blowdown enters in the tank above the waterline, maintained in the tank against a splash
guard. There is a vent on the top of the tank to prevent back pressure. The tank tank dischArge line is
also vented to prevent siphoning. The tank has a drain valve and a manhole for cleaning. The discharge
line is opposite the inlet, resulting in the cooler water being discharged first. Flash steam and or hot
water directly into the sewer may injure people or damage sewer line.
What is a plug valve. And why is it used on blow down lines. - answer-A plug valve has a circular tapered
plug ground to fit into there valve body. There is a hole through the plug that aligns with the valve body
when open. When turned closed the holes are misaligned. The shearing action cuts thru scale and will
not fall open.
What is a slow opening valve - answer-It is a screw type that requires at least five full turns from closed
to open.
Where is the bottom blowdown pipe connected to an HRT boiler? What type valves are used on the
bottom blowdown and in what order are they placed? How should you blowdown a boiler using those
valves? What size blowdown pipe? - answer-Underside of the shell, at the rear of the boiler
Two slow opening, or one quick and one slow opening valve
Quick valve is installed next to the boiler, opened first closed last.
Size 1 inch, not greater than 2 1/2. 3/4 is allowed on boiler less than 100sq ft
, P99 LOW PRESSURE BOILER EXAM REVIEWED QUESTIONS
AND COMPLETE CORRECT ANSWERS
When is the best time to blowdown a boiler, what important safety procedure do you observe - answer-
During light loads, sludge has settled to bottom.
Blowdown 10 seconds,
Once you open the valve do not take your hand off until valve is closed
How should a continuous blowdown be piped as it leaves the boiler and why? - answer-It will be piped
through a heats exchanger or flash tank to recover the heat. Then onto the blowdown tank
What is a continuous blowdown system and where is it installed - answer-Based on water analysis the
surface blowdown is monitored for continuous flow. The take off is located just below the NOWL in the
steam and water drum
What is a surface blow off? Where is it employed and why used - answer-Remove oil continents form
the surface of boiler water. The take off is located in the top 3" or 4" of water it controls the TDS total
dissolved solids.
On a Ashton type safety valve the label "O" and "S", what stand for and what adjustments can be made -
answer-Open And shut. Not certified to make adjustments
A boiler designed to operate at 125psi, know operates at 15 psi. What changes need to be made.? -
answer-Permanent change, safety valve larger disk and lower pressure rating with need to be installed
How do you determine if a boiler has sufficient safety valve capacity - answer-Accumulation test will
determine if the boiler discharges pressure, not allow pressure to build over 6% if MAWP
How must a safety valve be connected to a boiler - answer-1. Independent of any other steam
connection
2. Close as possible without any other piping
3. Screwed into the boiler shell or fastened to a flange welded to the shell
4. Connected to stand upright
