Module 2 Test Questions Heating/Hot Water Boilers

Question 1

Copper-tube boilers typically have:
a. better heat transfer characteristics, & longer lifespans than cast-iron boilers
b. better heat transfer characteristics, & shorter lifespans than cast-iron boilers
c. worse heat transfer characteristics, but longer lifespans than cast-iron boilers
d. worse heat transfer characteristics, but shorter lifespans than cast-iron boilers
e. roughly similar characteristics to cast-iron boilers

Answer 1

better heat transfer characteristics, & longer lifespans than cast-iron boilers

Question 2

Which of the following is a similarity between furnaces and boilers:
a. piping
b. low-level safety device
c. high-temp limit switches
d. pressure relief valve

Answer 2

high-temp limit switches

Question 3

Heat exchanger diagnosis on boilers is easier than on furnaces b/c the heat exchanger will leak when it has failed. T/F

Answer 3

True

Question 4

List 4 safety controls found on all hydronic systems.

Answer 4

1. pressure relief valve
2. high temp limit
3. low-water cutout
4. backflow preventer

Question 5

What is the normal operating pressure in a boiler?
a. 2 to 5 psi
b. 5 to 9 psi
c. 9 to 12 psi
d. 12 to 15 psi
e. 15 to 18 psi

Answer 5

12 to 15 psi

Question 6

What is the normal setting on the pressure-relief valve?
a. 10 psi
b. 20 psi
c. 30 psi
d. 40 psi
e. 50 psi

Answer 6

30 psi

Question 7

Where is the pressure relief valve typically located? Also, where does it typically discharge?

Answer 7

pressure relief valve is located on top of the boiler, & typically discharges near the floor

Question 8

Are we required to test the pressure-relief valve?

Answer 8

No

Question 9

Is it possible to have a pressure-relief valve that is too small for the boiler?

Answer 9

Yes

Question 10

What is the common temperature setting for the high temperature limit switch?
a. 180 degrees
b. 195 degrees
c. 210 degrees
d. 225 degrees
e. 240 degrees

Answer 10

210 degres

Question 11

What is the purpose of the low-water cutout on a residential boiler?

Answer 11

Low water cut-out prevents boiler damage if the system loses its water for any reason, Cutout prevents boiler from firing

Question 12

Why do we need a backflow preventer on a residential boiler?

Answer 12

prevent contaminated boiler water from flowing backwards into the domestic water piping if the domestic side loses pressure for any reason

Question 13

What is the safety control that prevents us from getting superheated water in a boiler system?
a. circulator
b. pressure relief valve
c. backflow preventer
d. pressure reducing valve
e. heat exchanger

Answer 13

pressure relief valve

Question 14

List 4 operating controls that we may find on a hydronic system

Answer 14

Thermostat; pressure reducing valve; primary control; pump control

Question 15

What is the function of the pressure-reducing valve?

Answer 15

pressure reducing valve drops the domestic water pressure down to the pressure required in the hydronic system.

Question 16

In a two-story Victorian home with a boiler in the basement you find a pressure-reducing valve set to 12 psi. Is there a possibility that this valve is set too low?

Answer 16

No

Question 17

Is it possible for a boiler to function without a pressure-reducing valve?

Answer 17

Yes

Question 18

You find a boiler with a low temp limit or primary control. What would be a typical setting for this control?
a. 50 degrees F
b. 100 degrees F
c. 140 degrees F
d. 180 degrees F
e. 220 degrees F

Answer 18

140 degrees F

Question 19

List 3 ways that the system can control a circulator (pump)

Answer 19

pump can be controlled by water temperature, by the burner control including the thermostat, or be wired to run continuously when there is electrical power to boiler.

Question 20

What are the 4 components in the distribution system for a hot water system?

Answer 20

1. pump
2. piping
3. radiators
4. convectors or baseboards & expansion tank

Question 21

What is the basic difference between an open system and closed system?

Answer 21

open system operates at atmospheric pressure, the closed system is pressurized. the open system does not have a pump & does not need a pressure relief valve. An open system does not have automatic water make-up (pressure reducing valve)

Question 22

Where is the expansion tank typically, in an open system?

Answer 22

above the highest level radiator

Question 23

What is the function of the expansion tank in a closed water system?

Answer 23

expansion tank allows water to expand as it is heated, so that excess pressure will not build up in the system

Question 24

Where is the expansion tank, typically, in a closed water system?

Answer 24

expansion tanks in closed systems are typically located near the boiler, often hung from the ceiling

Question 25

List 3 styles of circulators

Answer 25

1. pump & motor are mechanically coupled w/bearings that have to be oiled
2. pump & motor are close-coupled w/permanently lubricated bushings
3. pump & motor are close-coupled w/water lubrication

Question 26

List 3 materials that have been used for distribution piping in hot water systems in the past.

Answer 26

Black steel, copper, cast iron, plastic

Question 27

When a black steel pipe is extended with copper pipe, what can occur?
a. steel pipe may rust at the connection due to galvanic reaction.
b. circulator may not be able to overcome the pressure change at the junction.
c. copper pipe will wear through with the friction force of the water.
d. copper pipe will rust b/c of the galvanic reaction
e. nothing occurs when steel & copper piping are joined

Answer 27

steel pipe may rust at the connection due to galvanic reaction.

Question 28

In a radiant hot water heating system, the pipes serve 2 purposes. What are they?

Answer 28

Distribute heated water to the room, transfer heat to the rooms & return the cooled water to the boiler to be reheated.

Question 29

Mixing convectors and radiators in a single hydronic system will often result in uncomfortable heating. T/F

Answer 29

True

Question 30

Where should a radiator be placed in a room?
a. interior wall
b. exterior wall
c. exterior wall below window
d. on ceiling
e. it doesn’t matter, the radiator radiates heat to the room from any location

Answer 30

exterior wall below window

Question 31

Purpose of the bleed valve near the top of the radiator?

Answer 31

This allows the homeowner to remove trapped air from the radiator, letting the radiator fill w/water & heat the room effectively.

Question 32

Why do balancing valves tend to leak when operated?

Answer 32

Because they are turned rarely, the valve packing dries out & shrinks. When the valve is disturbed, a leak occurs here.

Question 33

What is the maximum ceiling temp you would want to have in an 8-foot room w/radiant pipe heating?
a. 70 degrees
b. 90 degrees
c. 110 degrees
d. 130 degrees
e 150 degrees

Answer 33

110 degrees

Question 34

DO radiant piping systems need bleed valves, since there are no radiators?

Answer 34

Yes

Question 35

What is the average lifespan of a cast iron boiler?

Answer 35

35 to 50 years