Hydronic Heating Period 2 (CND) Flashcards
What section of the ASME code do low temperature boilers fall under?
Section 4 of the ASME code.
True or False: Low Temperature boilers are usually gross rated?
False
The heat added to any form of matter that does not change its state but does change its temperature is called?
Sensible Heat
How many BTU’s of latent heat must be added to 10 pounds of water to change it to steam?
9700 BTU’s (10 pounds x 970 BTU’s = 9700 BTU’s)
To take 100lbs of water at 40F and heat it to 120F would require how many BTU’s?
8000BTU’s (120F-40F=80x1=80x100lbs=8000BTU’s)
True or False: 20.685Kpa is equal to 3psi?
True
Water is most dense at?
4C or 39.2F
What would be the likely cause of a boiler to over pressure?
Ruptured diaphragm in a bladder type expansion tank.
The color code for Type H copper pipe is?
White
Using the rule of thumb for bladder style expansion tanks what size of tank would be required for a heating load of 500,000 BTUh?
71 US Gallons
The type of boiler that can be used for space and domestic water heating is known as a?
Hybrid Boiler
What is the height restriction for an indirect fired blow through unit heater?
No Higher than 12”
As water is heated, its volume?
Increases and specific gravity decreases
An imperial gallon of water weighs 10lbs. How much does 18 cubic feet of water weigh?
1125lbs (18ft3 x 62.4lbs=1125lbs) *1ft3=62.4lbs
True or False: The term ASME stands for The American Society for Testing and Materials?
False: ASME - American Society of Mechanical Engineers
True or False: Boiler trim falls under section 4 of the ASME code?
False
1000 boiler horsepower is equal to ______BTU’s?
33,475,000BTU’s (1Hp = 33,475BTU’s)
A flow switch should be installed on a copper tube boiler when the exceed?
400,000BTUh
A BTU (British Thermal Unit) is?
The amount of heat energy required to raise 1lb of water 1*F.
A wall 8’x10’ has a combined R-value of 68 what is the U-factor?
U=0.0147
(U=1/R)
(U=1/68)
What is found on a high limit control that is not found on a opening control?
A manual reset button
All boiler make up water must be protected from cross connections by the means of?
Approved backflow preventer and D.C.V.A
What section of the ASME would you find boiler drain valves?
ASME 6
True or False: Draw through unit heaters can be installed in ceiling areas over 12’?
True
A boiler has a gross output of 427,000 BTU’s and an input of 750,000 BTU’s. What is its % efficiency?
56.9% (427,000/750,000=.569*100=56.9%)
The heating system where all the heating water passes through each heating unit is known as the ______ system.
Series loop system.
If a boiler has an input of 400,000 BTUh and is 98% efficient, what is its output?
392,000 BTU (400,000 x 98% or .98 = 392,000)
The amount of fuel consumed by a boiler is known as the ?
Input
True or False: High mass boilers can be low temperature or high temperature?
True
Modular radiant ceiling panels are available in two styles?
Even pass or uneven pass
Water will change to steam at what temperature?
212F or 100C
True or False: Smooth shiny surfaces will absorb radiant heat?
False
True or False: Expansion tanks are used to take up compression of the water in a heating system?
False
True or False: Dark rough surfaces will reflect radiant heat?
False
True or False: Guides and anchors are devices used to control expansion and contraction in piping system?
True
Unless specified, the temperature differential in a residential heating system is always?
20 Degrees
Which type of boiler extracts the latent heat out of the flue gases?
A high efficiency-condensing boiler
In a ______ heating system, the flow through one heat transfer unit cannot be shut off without stopping the flow through the other heat transfer units.
Series Loop heating system
True or False: Cavitation will not occur in a pump if the Net Positive suction head available (NPSHA) is greater than the Net Positive Suction Head Required (NPSHR)?
True
True or False: When two pumps are installed in parallel to each other, the system pressure will increase?
False
What is the flow required if you have a heat load of 186,350 BTUh, a supply temperature of 192F and a return temperature of 144F?
7.76gpm
(GPM = BTUh / 500lb/gpm x delta T)
(GPM=(186,350lbs x F) / 500lb/gpm x (192F-144*F)(GPM=186,350 / 24000gpm) Note-500lb/gpm is a constant
Which boiler is limited to a maximum working pressure of 30 psig (water) or 15 psig (steam)?
High mass cast-iron boiler
Within a hot water boiler, which device indicated pressure and temperature?
Combination Gauge
The device used to shut down the fuel to the burner when the water level in the boiler drops below its operating level is called a/an ___________ or a/an ________.
Float-operated low water cut-off or a Probe type low water cut off.
A globe valve pattern device that is used to reduce incoming water pressure to the minimum desired boiler system pressure and that also serves as an automatic water feeder is known as a _________ or _____.
Pressure reducing valve or PRV.
What are the maximum operating temperature and pressure of a low-temperature high mass cast iron hot water boiler?
120C (250F), 207kpa (30psig)
What is the maximum operating temperature and pressure of a low-temperature low mass copper or steel tube hot water boiler?
120C (250F), 1100kpa (160psig)
Low-temperature low pressure hot water boilers are usually rated in?
net BTU/hr or EDR
The amount of heat energy available at the heat transfer units is defined as?
The Net Rating
An EDR has a BTU valve of?
Steam 240 Btu/hr, Hot water 150 Btu/hr
The amount of heat energy consumed by the boiler is defined as?
The input rating
The piping system in which the heat transfer units are a part of the piping system is the?
Series loop