Electrical Circuits and Controls for Commercial Gas Appliances 080206c Flashcards
What is a pipe spool drawing?
The use of symbols to simply information and enable you to convey information in a clear and uncluttered manner
What is the most widely used type of schematic?
Ladder diagram
How is the exhaust fan in a direct fired make up air unit proven to be running?
Via interlock switches
What is a relay?
A device that opens or closes a set of electrical contacts and is activated by a coil
What is a contactor?
Works thr same as a relay but is larger
20 amps or larger is usually a contactor. Anything smaller is a relay
What is a coil?
Activates the contacts to either open or close
What is the purpose of an end switch?
Used to verify that a mechanical action has been completed and it is safe for another action to take place by closing or opening an electrical circuit
A high velocity air switch is what kind of switch?
Normally closed opens on pressure drop
How do you find VA?
VA = V x A
What are the 2 main types of gas valves?
Diaphragm and solenoid
What are the main gas valve or relay defined as on a electrical circuit?
Primary control
On a single valve installation, a bleed tube may be vented to an adjacent continuous pilot burner but what provisions must be met?
- bleed flame does not interfere with the safety control system (thermocouple)
- the inlet pressure is 0.5 psig or less
- the fuel is lighter than air
- the tubing material has a melting point in excess of 1450°F
What is a the purpose of a solid state rectifier?
Changes the current from ac to dc and can be used to regulate the speed of a blower motor
What is electrical power measured in?
Watts
How is electromotive force measured?
Volts
