Introduction To Hydronic Radint Heatng Design :A Flashcards
How much 1/2” tubing can be on one loop?
300ft
How much 3/4 tube can be on one loop?
500 ft
To determine tubing size what 3 factors must be known?
Gallons per minute flow rate
Length of circuit
Designed temperature drop through the circuit
What is the formula for GPM on a circuit?
What is the formulae to find the required BTU’ a per square foot required in a zone?
Btus divided by square feet of zone
In floor heating heats by
Convection and radiation
What is this piping layout called and used for?
Single serpentine
One exterior wall
What is this piping layout called and used for?
Double serpentine
2 exterior walls
What is this piping layout called and used for?
Triple serpentine
3 exterior walls
What is this piping pattern called and used for?
Counterflow
Heat loss is evenly distributed
What are the 4 installation methods for in floor radiant heating?
Poured in a concrete slab
Poured in an underlay on a suspended wooden floor
The sandwich method
Suspended below a wooden floor between joists
How close must fasteners be on rebar?
At least every 3’
Where else on the rebar must you put fasteners?
Each side of the arch and in the center
What is the maximum spacing between tubes embedded in a thermal mass?
Maximum 12”
What are the testing my parameters for in floor heating?
The greater of 60 psi or 1.5 times the working pressure for one hour with no pressure loss.
What do expansion joints in the concrete do?
Absorb horizontal movement cause by thermal expansion and contraction
A normally open zone valves power to do what?
Keep the zone valve closed.
A normally closed zone valve requires power to do what?
Requires power to open it.
A normally open zone valve requires why kind of thermostat?
Normally open thermostat
A normally closed zone valve requires what kind of thermostat?
Normally closed thermostat.
Installing the wrong kind of thermostat on a zone valve will do what?
Cause the valve to operate in reverse and supply heat when not required or remove heat demand when heat is required .
How long does an actuator type zone valve take to fully open?
3-5 minutes
Where are zone valves installed?
Prior to the manifold serving more than one circuit or directly on a manifold serving individual circuits.
Where is the thermostat for a zone valve installed?
The area with the greatest heat loss.
What can replace a zone valve?
A pump.
In a primary/secondary piping system what is the maximum distance between T’s?
4 pipe diameters to a maximum of 12”
What is this?
3 way mixing valve.
In what position is this 3 way mixing valve?
Fully open
What position is this 3 way mixing valve in?
Fully closed
In what position is this 3 way mixing valve?
Partially open (mixing)
When installing tubing in a radiant floor heating system which area of the room should the start of the loop be?
The areas with the greatest heat loss.
Is insulation required below a poured in concrete application?
Yes. Code requires it.
When are supplemental heating units installed in radiant floor heating systems?
When the radiant floor does not keep up with the heat load.
What two factors are required to calculate header size?
Gallons per minute and velocity .
Is a bypass pump between the supply and return piping required on a low mass boiler that is flow sensitive?
Yes
What is required when a conventional boiler is installed in a low temperature radiant floor heating application?
A mixing valve
What is the function of a 3 or 4 way mixing valve ina hydronic heating system?
Mixes water from the heat source and the system return in order to temper system supply water.
What must be installed with a three or four way mixing valve in order to protect the heat source and the radiant floor system?
A drive motor and controller .
What should be installed to separate the boiler water and system water when glycol is added to the water in a radiant floor heating system?
A plate heat exchanger
What is required when a variable speed injection pump is installed in a two temperature system ?
A controller for the pump.
