Massachusetts Stationary Engineer 3rd Class Thirds Written
Test Questions and Answers
Question 1
What are chlorides in water?
Correct Answer
Chlorides are suspended minerals in boiler feedwater (salts). They contribute to the Total Dissolved Solids in feedwater
which in turn relate to the conductivity. Chloride tests can be used to help determine boiler blowdown frequency. Since
these are dissolvable by water they can damage turbine blading if sent further into the steam cycle.
Question 2
Calculate the heating surface of 66 water tubes that have a 3 1/2inch O.D. 16 feet long.
Correct Answer
Watertube Boiler use OD
(3.5"/12") = .29167' (inches to feet)
.29167'*3.14 = .9158' (circumference in feet)
.9158'*16' = 14.65ft^2 surface per tube
14.65ft^2*66 = 967ft^2
Page 1 of 18
,Question 3
Blowdown tank what is it and piping requirements
Correct Answer
Blowdown tanks are used to reduce the temperature of feedwater that has been blown down before its sent to the sewer.
It cannot exceed 150F and 5PSI. Piping can be 1" to 2.5" from the boiler to the blowdown tank, if above 100 PSI, the
boiler must have 2 blowdown valves. Above 125 PSI the boiler must have schedule 80 or above piping. Blowdown tank
outlet piping is minimum 2", the blowdown vent is 10x the diameter of the inlet pipe.
Question 4
The cooling tower has a water level that is 80 feet high. What is the pressure at the suction of the pump?
Correct Answer
The pressure would be 34.6
1 Feet of Head = .433 PSI
1 PSI = 2.31 Feet of Head
So 80/2.31 = 34.6 PSI
or 80*.433 = 34.6 PSI
Question 5
What are the requirements for mounting 2 safety valves on a boiler?
Correct Answer
Boilers with over 500 sqft of heating surface are required to have at least 2 safety valves. ASME Section 1 - when not
more than two valves of different sizes are mounted singly, the cpacity of the smaller valve shall be not less than 50% of
that of the larger valve.
Page 2 of 18
, Question 6
When are two blowdowns required on a boiler?
Correct Answer
I am not sure of a circumstance where two blowdowns are required, I assumed they meant valves so thats what I
answered
Question 7
What is the procedure of starting a small non condensing steam turbine?
Correct Answer
1. Fill Grease Cups and oil governor
2. Open drains on the steam line, seperator, casing, and exhaust line. If equipped with traps open bypass
3. Slowly open exhaust line shutoff valve
4. If equipped with Aux pump, start pump
5. Inspect oil flow on bearings and pressure
6. Turn on cooling water for bearings or oil cooler
7. Open throttle quickly to start turbine, look for rubbing/vibrations/monitoring equipment
8. Slowly bring turbine up to 300rpm, stay at speed for 10-15 minutes
9. Trip emergency valve by hand to see if it closes properly, if it doesn't stop trouble shoot
10. Open throttle wide to let governor take control
11. Inspect bearings for oil
12. Close all drains that were opened
13. Gradually increase load according to manufacturers curve.
Page 3 of 18
Test Questions and Answers
Question 1
What are chlorides in water?
Correct Answer
Chlorides are suspended minerals in boiler feedwater (salts). They contribute to the Total Dissolved Solids in feedwater
which in turn relate to the conductivity. Chloride tests can be used to help determine boiler blowdown frequency. Since
these are dissolvable by water they can damage turbine blading if sent further into the steam cycle.
Question 2
Calculate the heating surface of 66 water tubes that have a 3 1/2inch O.D. 16 feet long.
Correct Answer
Watertube Boiler use OD
(3.5"/12") = .29167' (inches to feet)
.29167'*3.14 = .9158' (circumference in feet)
.9158'*16' = 14.65ft^2 surface per tube
14.65ft^2*66 = 967ft^2
Page 1 of 18
,Question 3
Blowdown tank what is it and piping requirements
Correct Answer
Blowdown tanks are used to reduce the temperature of feedwater that has been blown down before its sent to the sewer.
It cannot exceed 150F and 5PSI. Piping can be 1" to 2.5" from the boiler to the blowdown tank, if above 100 PSI, the
boiler must have 2 blowdown valves. Above 125 PSI the boiler must have schedule 80 or above piping. Blowdown tank
outlet piping is minimum 2", the blowdown vent is 10x the diameter of the inlet pipe.
Question 4
The cooling tower has a water level that is 80 feet high. What is the pressure at the suction of the pump?
Correct Answer
The pressure would be 34.6
1 Feet of Head = .433 PSI
1 PSI = 2.31 Feet of Head
So 80/2.31 = 34.6 PSI
or 80*.433 = 34.6 PSI
Question 5
What are the requirements for mounting 2 safety valves on a boiler?
Correct Answer
Boilers with over 500 sqft of heating surface are required to have at least 2 safety valves. ASME Section 1 - when not
more than two valves of different sizes are mounted singly, the cpacity of the smaller valve shall be not less than 50% of
that of the larger valve.
Page 2 of 18
, Question 6
When are two blowdowns required on a boiler?
Correct Answer
I am not sure of a circumstance where two blowdowns are required, I assumed they meant valves so thats what I
answered
Question 7
What is the procedure of starting a small non condensing steam turbine?
Correct Answer
1. Fill Grease Cups and oil governor
2. Open drains on the steam line, seperator, casing, and exhaust line. If equipped with traps open bypass
3. Slowly open exhaust line shutoff valve
4. If equipped with Aux pump, start pump
5. Inspect oil flow on bearings and pressure
6. Turn on cooling water for bearings or oil cooler
7. Open throttle quickly to start turbine, look for rubbing/vibrations/monitoring equipment
8. Slowly bring turbine up to 300rpm, stay at speed for 10-15 minutes
9. Trip emergency valve by hand to see if it closes properly, if it doesn't stop trouble shoot
10. Open throttle wide to let governor take control
11. Inspect bearings for oil
12. Close all drains that were opened
13. Gradually increase load according to manufacturers curve.
Page 3 of 18
