Introduction To Hydronic Radiant Heating Design Part A Flashcards
What is the size of a zone limited to?
Limited to the pump output, and the size of the manifold
What three factors must you know in order to size the tubing for zone sizing?
Gallons per minute flow rate
Length of the circuit
Designed temperature drop through the circuit
How to determine the gallons per minute required in a given circuit
Divide the total BTU by the US gallons X time(60 mins) and X the Delta T
Typical velocity in a residential application
2 to 4 ft./s
How do you determine the amount of tubing required for a zone?
Add all of the BTUs within the zone and divide by the total square-foot area of the zone
This determines BTU requirement per square foot
What is the pressure test testing method for in floor heat?
All system piping must be tested to the greater of either 60 psi or 1.5 times the working pressure
What do zones valves operate on?
24VAC signal to drive a motor or to energize an element that heats a liquid that causes a diaphragm to change length
What positions can zone valves be ordered in?
Normally opened or closed with or without end switches
This zone valve is a slow activating valve that takes 3 to 5 minutes to fully open
Actuator valves
Where is the thermostat that controls the zone valve typically installed
In the area of the greatest heat loss
The boiler must be equipped with the limit control for in floor to prevent what
Prevent the water temperature in the boiler from exceeding the design mean water temperature for the system
For primary/secondary piping what’s the spacing for tees
The tees must not be more than four system pipe diameters apart to a max of 12 inches
When is recommended downstream of a tempering valve?
A thermometer to verify the temperature
What’s what’s one circulator required on low mass boilers?
Bypass circulator
