Boilers and hydronics

Question 1

a pressuretrol operates due to

Answer 1

an increase in steam pressure AND a decrease in steam pressure

Question 2

pressuretrols that operate the main burner are manual reset.

Answer 2

false

Question 3

to set an additive operating pressurtrol that shuts the main burner ‘off’ at 130 psig and turns the main burner “on” at 120 psig, you the technician would set the adjustment screws as follows:

Answer 3

main scale setting 120 psig/ differential scale setting to 10 psig

Question 4

the maximum setting for a high limit pressurtrol on a low pressure steam boiler would be:

Answer 4

15 psig

Question 5

why do high input gas appliances with power burners require gas pressure switches?

Answer 5

because proper combustion would be affected if the manifold pressure varies too much

Question 6

the maximum setting on a high-pressure gas switch is:

Answer 6

25% in excess of the manifold pressure stated on the rating plate

Question 7

the minimum setting on a low pressure gas switch is:

Answer 7

50% less than the manifold pressure on the rating plate

Question 8

A LWCO should be installed to maintain what level of water above the highest set of tube in a fire-tube boiler?

Answer 8

1 inch

Question 9

referencing a float type LWCO what could happen if the blow down valve is opened too quickly?

Answer 9

the float could be damaged

Question 10

how often does a relief valve on a steam boiler have to be recertified?

Answer 10

every year

Question 11

the manual valve can be installed between the pressure vessel and the relief valve?

Answer 11

false

Question 12

the aquastat utilises this control principal to operate:

Answer 12

hydraulic

Question 13

the high limit aquastat utilised on a commercial hot water tank is known as:

Answer 13

ECO (energy cut off)

Question 14

An aquastat used to control the main burner would be considered:

Answer 14

Normally closed

Question 15

a flow switch on a hot water boiler system verifies operation of what device?

Answer 15

water flow through the boiler itself.

Question 16

an “indoor/outdoor” control controls what

Answer 16

water temperature

Question 17

a manual by-pass would be found on which of the controls listed below?

Answer 17

a NC zone valve

Question 18

A flow switch is not adjustable:

Answer 18

false

Question 19

a probe type LWCO uses this principle to operate:

Answer 19

conductivity of the boiler water

Question 20

which section of the ASME code details construction regulations of a packaged steam boiler with a design pressure of 15 psig?

Answer 20

ASME IV

Question 21

which section of the ASME code would you reference for operating and maintenance regulations for a section IV boiler

Answer 21

Section VI

Question 22

a packaged Low temperature hot water (LTHW) boiler operating at 150 psig with a temp of 230 deg F constructed under which section of the ASME code?

Answer 22

ASME IV

Question 23

which section of the ASME code would you reference for operating and maintenance regulations for a packed LTHW boiler?

Answer 23

ASME VI

Question 24

according to ASME code an unsupervised LP steam boiler requires ______ LWCOs:

Answer 24

2

Question 25

What agency is responsible for inspection and approval of LP steam and LTHW boilers in alberta?

Answer 25

ABSA

Question 26

what assembly is utilised to prevent a LP steam boiler from complete drainage on the event of a broken wet return line?

Answer 26

Hartford loop

Question 27

what is required when connecting a potable water make-up supply piping to a LP steam system?

Answer 27

reverse pressure back-flow preventor (RPBP)

Question 28

when installing a cast iron sectional steam boiler, if all the steam nozzles are not required, could the installer plug the nozzle outlets that are not needed?

Answer 28

false

Question 29

what is the grade required for a LP steam header

Answer 29

1/4”/ft

Question 30

what part of the LP steam boiler trim protects the burner controls from exposure to live steam?

Answer 30

syphon pigtail

Question 31

with regards to an additive DOPS, if the required system operating pressure is 10 psig and a differential set point is 2 psig, what should the main scale set point be?

Answer 31

8 psig

Question 32

which of the boiler/s listed below are considered low-mass?

copper fin tube
cast iron sectional
scotch marine
firetube

Answer 32

Copper fin tube

Question 33

all high-mass boilers over 400 MBH require what additional control?

Answer 33

LWCO

Question 34

An indoor/outdoor controller typically is a/an __________ control with a 1:1 ratio.

Answer 34

inverse

Question 35

if an indoor/outdoor controller is set for 65 deg F with the boiler water supply temperature operating at 160 deg F and the temperature outside drops to 20 deg F, what will be the new operating temperature set point of the boiler supply?

Answer 35

205
65 + 160 = 225 - 20 = 205 deg F

Question 36

a probe type LWCO operates due to the principle of?

Answer 36

Conductivity

Question 37

what is the maximum set point for a safety relief valve installed on a LTHW boiler?

Answer 37

30 psig or 160 psig depending on the maximum design pressure of the boiler

Question 38

Boiler safety controls and the pop safety revive devices are recommended to be checked:

Answer 38

monthly

Question 39

who is responsible for supplying your worksite with any necessary personal protective equipment specified by OH&S?

Answer 39

the employer

Question 40

which portion of the light spectrum can cause “welding flash” to a worker without the proper eye protection?

Answer 40

ultraviolet

Question 41

which type of a clothing material has a tendency to melt when in contact with a flame?

Answer 41

polyester AND nylon