Hydronics Flashcards
Test
What are the three functions of a triple duty valve?
Pressure reducing, check valve, balance in valve
What are three devices that would be included in a makeup water system?
Prv, backflow preventer, isolation valve
What does lwco stand for?
Low water caught off
How many BTUs are required to heat one pound of water from 32° to 212° f?
180
How many BTUs are required to change 1 lb of water at 212° f to steam?
970
What valve would you choose to regulate flow through a coil?
Pressure reducing valve
What device is used to protect potable water systems from cross-contamination?
Backflow preventer
What device protects the boiler from pressure above maximum design pressure?
Pressure relief valve
What does asme boiler code require if the output of a boiler is 400,000 BTU or more?
Low water cutoff
The BTU rating of a boiler is how much heat the boiler will create and how long?
1 hour
When a heat pump is in heating mode what is the operating mode of the outdoor device?
Evaporator
In a coil what type of flow has the best heat transfer?
Counterflow
True or false. You need 10 pipe diameters of straight pipe between the y strainer and the suction for the pump.
False
When connecting the makeup water fill line, what is the best location for installation?
Point of no pressure change
When a pump is subject to a lift what must be done to the pump before you start the motor?
Prime it
Which term describes a hydronic system that is sealed to prevent entrance of air from the atmosphere?
Closed
Why is glycol not used at 100% concentration?
Viscosity is too high
Which pump is used most often for a closed hydronic piping system
Centrifugal
In a primary - secondary pumping arrangement where is the largest circulator installed?
Primary
Where would you install a triple duty valve
Discharge of the pump
What is the maximum spacing recommended for the closely space tees on a primary - secondary system?
Four pipe diameters
What are the two types of pump misalignment that must be checked?
Angular and parallel
What is the violent action of vapor bubbles in a centrifugal pump?
Cavitation
What is the maximum theoretical lift of a pump?
34 ft of head
If you are going to convert PSI to foot head what is the equation that you would use, and if you were going to convert foot head to psi what equation would you do.
Psi to ft of head = x.433
Ft of head to psi = x2.32
Which piping system is identified by first supplied last to connect in the return?
Direct return
Which system has separate heating and cooling functions with dedicated supply and return piping?
For pipe
Which piping designs are two pipe systems?
Direct return and reverse return
Which type of hydronic system would use gravity flow
Low temperature heating
Brian or water/glycol mixture is commonly referred to as?
HTF
In order to provide accurate indoor temperatures the heat supply to the building must be equal to?
Heat loss of the building
What are the four types of heat transfer?
Conduction, convection, radiation, evaporation
Which type of heat, when added or removed from a substance creates a change of state?
Latent heat
Define humidity
The amount of moisture in the air
What is dry bowl temperature?
Temperature of air taken with a standard thermometer
How is rate of flow measured?
Gallons per minute
Which tool is used to determine relative humidity?
Sling psychometer
Which heat transfer describes the condition when a body loses heat to cooler surfaces?
Radiation
Pressure, according to the height of a liquid is called?
Static head
What is atmospheric pressure at sea level?
14.7 psia
Temperature comfort is accomplished by controlling
Temperature and humidity
Describe enthalpy
Total amount of energy of a substance
What is another term for pump capacity?
Head pressure
Evaporation occurs when water absorbs _____ heat
Latent
What is maximum design pressure for a low temperature boiler?
160 PSIG
A condenser acts as a type of?
Heat exchanger
Low pressure boilers are classified by?
15 PSIG steam and 160 PSIG water
Which type of device is attached to a boiler to assist in the management of air in a hydronic system?
Boiler fitting
Which impeller is most efficient for pumping clear liquids?
Vane and pedal
which term describes an impeller that has vanes attached to a hub that is not enclosed or supported by a shroud on either side?
Open impeller
The best place for air separation is at the boiler why?
HTF is at a high temperature and low velocity
A typical pressure at the top of a hydronic system with the pumps off would be?
4 PSIG
Select three ways air can exist within a hydronic system?
Air pockets, entrained air bubbles, dissolved gases
Which flow rate is best for air removal?
2 fps
A properly installed closed loop hydronic system that has been filled and properly maintained, needs ______ additional HTF
Rarely
2 types of 1 pipe systems
Series loop and single main
