Unit 22 - Chapter 98 Flashcards
In a forced circulation system the expansion tank allows the system to operate at
A pressure well above atmospheric pressure
The maximum temperature of water in a gravity hot water system is
77’C
A forced hot water circulating system can be classified as the following type
- loop system
- one pipe system
- two pipe direct return system
- two pipe reverse return system
In a one pipe hot water system the fitting that directs the water to each converter is called the
Diverter
In a radiant heating system the maximum surface temperature is
30’C
In radiant heating system changes are
Difficult to make
Automatic snow melting systems can use
- hot water and antifreeze mixed
- electric resistance heating
- infrared lamps mounted above sidewalks and ramps
- hot water and ethylene glycol mixed
Snow melting systems are usually filled with
Ethylene glycol and water
Advantages of forced circulation hot water heating systems are
Reduction in pipe size and greater heat storage capacity
A hot water boiler of the same output is
Smaller than a steam boiler
In a hot water system compared to a steam heating system, if there is a leak damage will
Be greater in the water system
Which use a boiler in the system?
- steam heating
- steam to hot water system
- hot water heating
Diverted fittings are used in the supply lines to heating units
When a higher heating output is required from the heating unit
An air separator should be installed in
A horizontal pipe
The air removed by the air separator is vented to the
Expansion tank
To ensure that each zone circuit has the proper flow of water to provide the required heat, a
Balancing valve is used
The temperature control on a steam to hot water converter controls
The steam control valve
A hot water system circulates water through the pipes with which pump?
Forced
Which is not an advantage of a hot water system compared to a steam heating system?
Maintenance costs are usually higher in a hot water system
The maximum temperature of the water in radiant panel heating coils for ceilings is about
80’C
One of the advantages of the hot water heating as compared to steam heating is
Lower maintenance costs
A hot water system which circulates water through the pipes with a pump is known as a
Forced circulation system
The disadvantage of a series loop hot water heating system is
The individual convectors cannot be shut off
The two pipe reverse return system has the advantage of
All circuits have the same length
Which is not a hydronic heating system?
A wet return system
Because of the different circuit lengths to each convector, the direct return hot water system is difficult to
Balance
In a radiant heating system the maximum surface temperature of the walls is
38’C
The working pressure and temperature of most residential and commercial applications are
85 - 140 kPa
70 - 94’C
Series loop systems
Are the cheapest piping system possible
One pipe systems use ___ to ensure adequate flow thorough each convector
Special diverted/Venturi tee fittings
In the two pipe direct system
The temperature of water entering each convector is the same for all, while all circuit lengths are different; pipe size is critical for equal flow.
In two pipe reverse return systems
All circuits have the same length and all connectors receive the same amount of water at the same temperature; pipe size is not as critical.
The temperature of water in coils of radiant panel heating systems should not be higher than
80’C for ceilings and 60’C for floors
In radiant panel heating, the surface temperature should not exceed
46’C in ceilings, 38’C in walls, and 30’C in floors
