3Rd Year Heating Final

Front 1

What code deals with hydronic heating systems?

Back 1

B-214

Front 2

How does a forced air system heat a room?

Back 2

From the ceiling down

Front 3

How does a radiant floor system heat a room?

Back 3

From the floor up

Heats the objects in the room

Front 4

5 disadvantages of radiant floor heating

Back 4

1) initial cost

2) building structure

3) room temp set back- slow responding

4) no way to filter or humidify air

5) must have a separate make up air

Front 5

3 types of tubing

Back 5

1) metallic-soft Cu

2) synthetic-PEX

3) composite- Al sandwiched between plastic (impervious to O2 permeation)

Front 6

Maximum lengths of tubing:

1) 3/8"

2) 1/2"

3) 3/4"

Back 6

1) 3/8=250'

2) 1/2=300'

3) 3/4=500'

Front 7

Manifolds are constructed from ____, ____, or _____

Back 7

Cu, brass or plastic

Front 8

Desired flow rate for residential installations

Back 8

2-4 feet/sec

Front 9

When are balancing valves required and what is their purpose?

Back 9

Balancing valves ensure equal flow rates to each circuit connected to a manifold. Required when there is more then a 10% difference between the longest and shortest circuit

Front 10

Max floor temp where people stand for a long period of time

Back 10

77•F

Front 11

Air that enters the building thru cracks and openings

Back 11

Infiltration

Front 12

floor temp in a dwelling or commercial building

Back 12

88•F

Front 13

Floor temps in bathrooms, swimming pool areas or foyers

Back 13

91•F

Front 14

Floor temp around the perimeters of rooms

Back 14

95•F

Front 15

U-factor

Back 15

Amount of heat transmitted

U= 1/R

R=resistance to flow. The higher the R factor the lower the amount of heat transferred.

Front 16

2 factors that determine the right pump for an application

Back 16

Flow rate and pressure loss

Front 17

What determines flow rate?

Back 17

Amount of heat delivered and temp drop (GPM)

Front 18

Boilers with cast iron ht exchangers are classified as _____ _____ boilers. They are best suited for applications that do not require _____ flow rates and ____ recovery

Back 18

High mass boiler

Best suited for applications that do not require high flow rates and quick recovery

Front 19

Low mass boilers require ____ flow and ____ return temps. They are best suited for applications that require ____ flow rates and quick temp response. Ht exchangers are normally constructed from _____ or ______ tubes

Back 19

Require constant flow and higher return temps. High flow rates. Steel or copper tubes

Front 20

Conventional boilers must operate at temps above?

Back 20

140•F

Front 21

How do you calculate the gross rating or output of the boiler?

Back 21

Add 15-25% to the net rating for transmission and pick up load losses

Front 22

What are transmission losses?

Back 22

Btus lost as piping delivers heat to an area. Jacket and stack losses. Insulation decreases heat loss

Front 23

What is the end result of O2 corrosion? And what does it cause??

Back 23

Scaling. Builds up on internal walls of the ht exchanger and reduces the amt of heat transferred.

Front 24

What is pick up load?

Back 24

Btu required to heat the heat transfer before the space can receive any heat

Front 25

What is a disadvantage of polyethylene tubing?

Back 25

Can become breeding grounds for bacteria and reduce ht transfer

Front 26

In radiant heating systems where does freeze up normally occur?

Back 26

Slab-on-grade applications

Front 27

What are the 2 most common types of glycol?

Back 27

Ethylene glycol-extremely toxic and corrosive and high temps

Propylene glycol- food grade non toxic

Front 28

Most pump bodies cast from ___, ____, or ____

Back 28

Steel, bronze, stainless steel

Front 29

What is recommended if glycol is to be used?

Back 29

A separate ht exchanger

Front 30

When glycol is used how much should you increase the size of the expansion device?

Back 30

15-20%

Front 31

A heating system is designed for the ___ days. Which typically represents _____% of the normal heating season

Back 31

Coldest. 4%

Front 32

Where is the lowest pressure point in a pump?

Back 32

At the inlet of the pump

Front 33

What keeps a liquid in liquid form?

Back 33

Vapour pressure

Front 34

What is required to properly size a boiler?

Back 34

Total heat load required for the building

Front 35

What type of boiler is best suited for infloor heating?

Back 35

Condensing

Front 36

Design temp difference =

Back 36

Indoor design temp-outside design temp

Front 37

What is the recommended practise for determining room dimensions?

Back 37

Round up or down to the nearest 1/4 of a foot

3"=0.25

6"=0.5

9"=0.75

Front 38

What causes frequent cycling of a boiler?

Back 38

A boiler with an output that is too high for the application

Front 39

Steel pumps are best suited for?

Back 39

Applications using ferrous materials and systems with minimal amounts of O2 permeation

Front 40

When you calculate heat loss thru a wall made of one material you use? Thru a wall made of many materials you use?

Back 40

One material use k value. Many materials you use u value

Front 41

Bronze and stainless steel pumps are best suited for?

Back 41

Applications that use non ferrous materials and maybe prone to O2 permeation

Front 42

All pumps are ______ by design. Liquid moves faster at the ____ of the impeller than the _____. Liquid is then gathered in the ____ where _____energy is converted to ____ energy

Back 42

All pumps are centrifugal by design. Liquid moves faster at the tips of the impeller then the eye. Liquid is then gathered in the volute where velocity energy is converted to pressure energy

Front 43

Circulating pump must be installed with the motor shaft in what position?

Back 43

Horizontal position

Front 44

The primary circuit pump is typically installed?

Back 44

At the point of no pressure change downstream of the expansion tank. This ensures a positive pressure at the suction side of the pump and eliminates the chance of cavitation

Front 45

How many pumps are required in a 4-way mixing valve application? And what are their functions??

Back 45

2 pumps. The primary pump circulates water thru the boiler side piping and the mixing valve. The secondary pump draws water thru the 4-way mixing valve and circulates it thru the system side. 4-way Mixing valve ensures boiler always receives flow

Front 46

How many pumps are required in a 3-way mixing valve application and what is its function?

Back 46

One pump. Circulates water thru the system side

Front 47

What is deadheading and how do you prevent it?

The best way

Back 47

Deadheading is blocking or closing the outlet of a pump while it's still operating. Liquid boils and causes cavitation. A bypass must be installed to allow constant flow

Front 48

The size of a zone is limited to the pump ____ and the size of _____

Back 48

Pump output and size of manifold

Front 49

The best way to size a zone is by _____, _____ and ____

Back 49

Comfort, efficiency and cost

Front 50

What 3 factors are needed in order to size tubing?

Back 50

1) flow rate (gpm)

2) length of circuit

3) designed temp drop

Front 51

Formula for calculating GPM:

Back 51

Total btus per hour/8.33*60*temp change

Front 52

Pressure test

Back 52

60 psi or 1.5 times the working pressure for 1 hour

Front 53

Temperature of the water circulating thru the tubing is referred to _____ _____ temp. what do you need to calculate it?

Back 53

Mean water temp

Btu/hr/sq ft, indoor design temp and the total r value of the materials above the tubing

Front 54

Which layout pattern should be used when one exterior wall?

Back 54

Single serpentine

Front 55

Which layout should be used when there is 2 adjacent exterior walls?

Back 55

Double wall serpentine

Front 56

What layout should be used when there are no exterior walls and therefore heat loss is evenly distributed?

Back 56

Counter flow pattern

Front 57

When securing tubing where do you fasten it?

Back 57

Every 3 feet, at the start and top of the arch

Front 58

The max tube spacing in an embedded thermal mass shall not exceed ___"

Back 58

12"

Front 59

At exp joints the tubing is run thru a rigid sleeve that covers the tubing for at least ____" on either side

Back 59

12"

Front 60

Manufacturers will not warranty ____ contamination of the boiler water

Back 60

Oxygen contamination

Front 61

The safety relief valve discharge pipe shall be ____" above the floor or drain

Back 61

4"

Front 62

Do not use a t-stat with a ___ _____ with a boiler.

Back 62

Heat anticipator

Front 63

When a tubing suspension method is used, the floor is heated by ____

Back 63

Convection

Front 64

What is the max tube spacing when installing in poured in concrete?

Back 64

12" c-c

Front 65

What 3 factors are needed to properly size tubing?

Back 65

Gpm,velocity and length of circuit

Front 66

What 2 factors must you know in order to determine floor surface temp?

Back 66

Btu/sq ft and room temp

Front 67

What 2 factors are required to calculate header size?

Back 67

Gpm and velocity