Hydronic Self Test Questions Flashcards
What are the 5 types of heat loss?
1) Radiation
2) Evaporation
3) Convection
4) Conduction
5) Respiration (so min doesn’t count)
What is the approx.. % of heat that a human body loses by radiation?
48%
What is the phenomenon known as, where a person can feel cold b/c they are sitting too close to a window or exterior door, when the temperature setting in the room is normal?
Cold 70
What is the name given to the set of interior room temperature conditions where the human body feels the most comfort?
The ideal heat curve
What is the temp that is read on a thermometer indicating?
The intensity of a heat present
What is the formula when calculating the BTUs involved in heating of water within a heating plant (ex: boiler)
BTUs = Mass x temp diff x S.H
What is the temp differential used in the design of most hot water heating systems that are fed from a boiler?
20 F
What is the min return water temp that should be maintained when using a non-condensing boiler?
140 F
What is the term known as, where heat is able to be applied to only the areas of a building where it is needed, rather than to the whole building?
Zoning
What would the K value for a material that has an insulating value of R = 22?
0.045 (1 divided by 22)
When designing a heating system, what is the January 2.5% value for the geographical area known as?
The Outdoor Design Temp
What is the allowable IDT that can be used residentially when performing a heat loss estimate if hydronic radiant panels are intended as the primary source of heat?
68 F
What is the allowable IDT for an unfinished basement?
18 C –> 64 F
In heat loss language, what is the term for heat that is lost from a building through conduction?
Transmission
What is the term for heat that is lost when cold air makes its way into the building through cracks / imperfections in the buildings envelope?
Infiltration
What would give a double - glazed window the best insulation rating?
Low “E” - Argon filled
What is the term given to the situation where, a heated slab-on-grade butts up to the exterior foundation wall, allowing heat to transfer between the two materials more easily than through the surround structure?
Thermal bridging
What would be the expected outcome of the rate of heat transfer if the temp diff. between two sides of a wall or ceiling were doubled?
The rate would double
What would be the expected outcome of the rate of heat transfer if the “R” value of a material were doubled?
The rate would be halved
How many air changes / hour (ACH) would a room with openings on 3 sides undergo?
1
What is the “R” value of 3” of extruded polystyrene?
15.0 (3 x 5.0 / inch)
Which variety of PeX tubing is manufactured by the Engel method / has a memory?
PeX A
Which variety of PeX tubing requires an oxygen - diffusion barrier when used in radiant floor panels?
PeX A, B, C
What min thickness of rigid polystyrene foam should be placed under a basement concrete slab that is heated by radiant mean?
2 1/2”
If a repair connection must be installed in a loop in a concrete over wood subfloor panel, where should the joint be located?
In the ceiling below
What is the purpose of the wide, extra bottom plate in above grade walls of a radiant floor panel system?
1) to allow for carpet nailing strips
2) Act as screed for the second concrete lift
3) to make up 1 1/2” of ceiling height that the concrete takes from the room
What takes the place of a boiler in a snow melt system / effectively separates it from the building’s heating system to prevent the entire system from having to be freeze protected?
A heat exchanger
What are radiant floor systems known as that heat the joist space below a floor?
Dry systems
What is installed along with batt insulation between joists that causes heat to be driven upward instead of downward?
Reflective foil
Does radiant ceiling panels operate at low temps?
No, at high temps
How would you lay radiant tubing loops in rooms that have 1 or 2 outside walls?
first pass = 6” from outside wall
turn 180
another 6” pass
resume normal loop layout
What is the max floor output from a radiant panel, in areas where people spend much time, over which supplemental heat will be necessary?
40 BTUH / ft2
What is generally the longest suggested loop length for 1/2” radiant tubing at a 20 degree pressure diff.
300 feet
What is normally used to locate tubing operating and embedded in a residential concrete floor?
an infra-red thermometer
Which multiplier would be used when determining the total tube required for a room with tubing laid at 6” O.C spacing
2:1
To what pressure / for how long should tubing be tested before being poured into a concrete mass?
100 psi / 30 min
What is the main characteristic of a boiler is used when choosing it?
its output
When assigning a head loss to a circulator, what is used as the head loss for the piping?
The single circuit w/ the highest head loss served by the pump
What are the 2 variables that are used in choosing a circulator?
Flow rate and feet of head
How many millinches are there in one foot?
12,000
What variety of valve is a circuit setter?
Globe
What is the name given to the strategy that uses a motorized mixing valve to automatically adjust its temp setting in reaction to changing outdoor or system thermal conditions?
Reset control
What is the term given to the practice of ensuring that the operation of one pump doesn’t affect the operation of another, if they share common piping?
Hydraulic separation
What characteristic of a brazed plate heat exchanger accounts for its high rate of heat transfer?
It’s inner plate surface area
What type of valve can be installed between the supply / return mains that will open when the pressure in the supply main gets too high, as might happen when only one or two zone valves are open and there is only one system pump?
A differential bypass valve
If 2 pumps are installed in parallel with each other, the approximate what will double?
Flow rate
What is the moving part of a switch known as?
The pole