Hydronics Flashcards
T or F
A compression tank is not necessary in a system if a reducing valve is used?
F
T or F
It is best to connect the make-up water line into the air line going to the compression tank?
T
Why is the boiler chosen for air separation?
Due to the lower flow rates within the conventional boiler and because this is where the highest temp in the system occurs.
What effect does static pressure have on pump capacity?
Static pressure in a closed system has no effect on pump capacity
In what three ways does the human body lose heat?
Radiation
Conduction and convection
Evaporation
What effects will become immediately apparent if air is allowed to leave the compression tank and get into the system?
A gravity circulation between the tank and the system will occur causing the tank temp to approach that of the system
What is the maximum working pressure of the average hot water boiler?
160 psig
And 30 psig.
I’m gonna put both. If I see this question.
Why may a hot water boiler designed for hot water, never be used for steam?
Hot water boilers are limited to a max working temperature of 250°f. It might not be able to handle the high pressure and temp required for a steam system.
Define the term hydronics?
Hydronics is the heating and or cooling system that uses water and or another fluid as a heat transfer medium to move heat from one area to another.
List five acceptable requirements for an ASME hot water relief valve.
The valve is constructed in accordance with ASME requirements
It must have a tag with the proper BTU-H rated capacity
The rated capacity should match match the gross output of boiler .
It must be properly installed at correct location.
The try lever provides a means of testing.
Explain the operation of the reverse return system.
The first terminal unit taken off the supply main is the last to connect to the return main.
What happens to the water in all hot water boilers as the temperature of the water increases?
It begins to expand as the temperature rises.
What is one of the basic diff between the single main and two-pipe system?
The 2 pipe system has a separate supply and return main that can overcome higher pressure drops than what a diversion valve can handle.
What is pressure drop?
Pressure drop is the amount of pressure lost between any two points in a system.
What are the four basic components parts of a water chiller?
The compressor
The evaporator
The condenser
The refrigerant
Describe the piping arrangement of a three pipe-system .
A hydronic heating and cooling system consisting of a hot supply main , and a common return main.
What causes pressure drop?
The friction created between the inner walls of pipe and fittings and the liquid flowing through them.
What is the term applied to the height to which the cooling tower pump must elevate water?
Static discharge head = the vertical distance the liquid is being pushed as measured from the center of the pump discharge to the point of open discharge.
Where must the expansion tank be located in a gravity hot water system
At the highest point usually open to atmosphere.
Why must air never be completely eliminated from the system?
It acts a cushion or compressed spring which allows for thermal expansion and equal pressure to all parts of the system.
What is a good definition of comfort.
The condition in which the human body feels neither warm nor cool and is at thermal equilibrium with the ambient temperature.
List three types of hydronic piping systems.
Two-Pipe System
Three-pipe systems
Four pipe systems
What causes the water to circulate in a gravity hot water heating system.
The heated HTF will naturally rise within a large system; whn it cools from the loss of heat it will gravitate downward creating the natural circulation.
What must be done to the piping leading from the boiler to the compression tank.
It must always be pitched up and be large enough in diameter to allow water and air to pass each other at the same time.
Why should a mixing valve not be interchanged with a diverting valve?
It would short cycle your terminal units if the mixing valve is in the wrong spot.
What may be done to reduce the size of a compression tank?
Place it as high as possible in the system.
Mixing valve and pipe system drawings.
Mixing valve and pipe system drawings
Mixing valve and pipe system drawings
Mixing valve and pipe system drawings
Mixing valve and piping system drawing
Mixing valve and piping drawings
2 pipe parallel flow system drawing
And
2 pipe reverse return system drawing
