Hot Water Heating Systems

Question 1

Hot Water (Or Hydronic) heating systems provide comfort heating by:

Answer 1

Using a central boiler to heat water

Question 2

The two basic types of hydronic heating systems are

Answer 2

Gravity Systems

Forced Flow Systems

Question 3

Gravity systems rely on what 2 things to promote movement of water in the system?

Answer 3

Convection currents within the piping system

Density of cold water versus hot water

Question 4

Forced Flow Systems provide greater flexibility in design and operation by

Answer 4

Using a pump to move the heating water

Question 5

Why did the hot water heating system become popular?

Answer 5

Safer than the steam systems

Question 6

What were the drawbacks of gravity hydronic heating systems?

Answer 6

More costly due to larger piping required

Slow response time

Question 7

Forced Flow Hydronic Heating Systems use a _____ or circulator to move heated water through a piping distribution system.

Answer 7

PUMP

Question 8

A _____ system is NOT open to the atmosphere.

Answer 8

CLOSED

Question 9

Boiler temperature is controlled by the

Answer 9

High and low limits of the temperature controller.

Question 10

Microprocessors can control ______ lights that show the operational state of motors, valves, pumps, and temperatures.

Answer 10

INDICATOR LIGHTS

Question 11

Digital Controllers increase energy efficiency and provide

Answer 11

diverse control strategies, safety interlocks, and other options requested by customers.

Question 12

What device transfers heat energy to the surrounding air or space from the hot water?

Answer 12

Heat Transfer Unit

Question 13

Power circuits for boilers must have a

Answer 13

DISCONNECT SWITCH

Question 14

Boilers are the heart of every hydronic heating system. They use ______ to heat the water that in turn heats the building.

Answer 14

FUEL

Question 15

Boilers with cast iron sectional heat exchangers are

Answer 15

Heavy and hold a large volume of water compared to other boilers of the same capacity.

(High-Mass Boilers)

May be used with gravity heating systems

Question 16

Direct Vent continuous flow heat exchangers may be made of

Answer 16

stainless steel, steel, cast iron, or copper

Question 17

Larger Projects like apartment buildings use multiple:

Answer 17

Direct vent Boilers.

Can be combined to produce input values up to 1000 Mega BTU per hour

Question 18

Standing pilot flame ignition has a pilot flame that burns constantly and is in direct contact with the:

Answer 18

Thermocouple near the main burner

Question 19

Direct Spark ignition uses a high voltage source to create :

Answer 19

A hot spark across a spark plug

(10,000V Transformers)

Significant shock hazard.

Question 20

Hot Surface Ignitions are _______ ignition devices similar to the heating element in a toaster.

Answer 20

Resistive

Question 21

A pyrostat AKA a stack switch is a :

Answer 21

Bimetal coil incorporated inro a probe.

Question 22

A cad cell is:

Answer 22

A light sensitive cell mounted so light from the flame strikes it directly

Question 23

With no light the cad cell has very high resistance. When it sees light from the flame, the resistance drops to between ______ and ____ ohms and allows current flow.

Answer 23

300-1000ohms

Question 24

Circulating pumps typically have a power rating up to ____ hp and operate at speeds between ____rpm and ______ rpm

Answer 24

1 hp

1750 RPM - 3450 RPM

Question 25

Recommended safety and control devices include:

Answer 25

Low water cut-outs Temperature Control Devices Aquastats Flow Switches High Limit Control Devices

Question 26

What does the low water cut out do?

Answer 26

Shuts off the fuel supply to the burner if the water in the boilers falls below acceptable levels

Question 27

The most common type of Low water cut out is a

Answer 27

float operated device

Question 28

What are the two basic parts of temperature controls?

Answer 28

Zone Air Temperature, which is controlled by a TSTAT in that zone Boiler Temperature, which is controlled by an AQUASTAT on the boiler.

Question 29

Aquastats are ________ devices that react to water temperature.

Answer 29

Switching.

Question 30

Define Reverse acting control

Answer 30

A strategy which prevents the start up of the circulating pump until the boiler water reaches a minimum temperature.

Question 31

TRUE OR FALSE The relief valve is a last resort to ensure the boiler does not exceed maximum working pressure.

Answer 31

TRUE

Question 32

Safety Flow Controller Limits sense:

Answer 32

The velocity of the water in hydronic heating systems and interrupt the heating circuit if the velocity is too slow.

Question 33

Mechanical controls use _____ or ________ action in the system to operate.

Answer 33

PRESSURES MECHANICAL ACTION

Question 34

The two types of expansion tanks are:

Answer 34

Compression Tanks Diaphragm Expansion Tanks

Question 35

What is the difference between a compression and diaphragm expansion tank?

Answer 35

Compression tank is physically much larger and has no internal diaphragm

Question 36

The point where the expansion tank connects to the hydronic system is called the

Answer 36

Point of no pressure change

Question 37

Line air scoops remove:

Answer 37

Air bubbles from the hydronic system

Question 38

Automatic Air Vent Valves are:

Answer 38

Devices that allow air bubbles trapped in a hydronic heating system to bleed to atmosphere while maintaining pressure and preventing water from escaping.

Question 39

An Automatic Air Vent Valve is a

Answer 39

Mechanical float valve

Question 40

Pressure relief Valves prevent:

Answer 40

Unsafe internal water pressure in hydronic boilers.

Question 41

Checking the valve mechanism is called a

Answer 41

POP TEST or TRY TEST

Question 42

Pressure Reducing Valves feed ____________ city water into the hydronic heating system

Answer 42

Reduced-Pressure

Question 43

City water supply pressure is between ____ PSIG and _____ PSIG

Answer 43

50-70 (350-480 kPA)

Question 44

Normal hydronic heating operational range is

Answer 44

15 PSI to 30 PSI

Question 45

What are the 3 basic types of gauges found in commercial hydronic heating installations?

Answer 45

Temperature Gauges Pressure Gauges Combination Temperature and pressure gauges.

Question 46

Chemical treatment feed pots allow the operator to

Answer 46

introduce liquid chemicals while it is operating and under pressure.