Heating Flashcards
What is secondary air?
Air added at the flame
What are two optional information that could be seen on rating nameplates?
Orifice size and Output
What is considered high altitude for a furnace?
2000 to 4500 ft
How much percentage do you de-rate an altitude at sea level for a high altitude application?
10%
Extra high altitude (above 4500 ft) needs to be de-rated what percent per how many ft
4% for every additional 1,000ft
What is flashback?
Low manifold pressure causing slow gas/air mixture
What is flame lift-off?
Manifold pressure too high causing over fire because high velocity gas/air mixture.
What are the two types of burners?
Power burners and atmospheric burners
What is the difference between a power burner and an atmosoheric burner?
Power burners use motors to supply combustion air. Atmospheric burners use the Venturi effect.
Three different types of pilot burners?
Non-aerated, aerated, post aerated
What is the difference between aerated and non-aerated flames?
Non-aerated flames do not use primary air. only secondy air for combustion.
Aerated Flames use secondary air giving 2 distinct cones.
What type of primary/secondary air balance is found in a Aerated, oxidizing flame?
Large amount of primary, little secondary.
What type of primary/secondary air balance is found in a Aerated, Neutral Flame?
Medium primary and secondary air
What type of primary/secondary air balance is found in a Aerated, Carburizing Flame?
Small primary, a lot of secondary. large inner cone.
What does an appliances input rating represent?
Amount of gas the appliance can safely handle
What does an appliance output rating represent?
The difference between what it consumes and what is being supplied to the appliance
What are four types of pilots?
- Continuous
2.Expanding
3.Intermittent
4.Interrupted
True or False a continuous flame turns off
False, its always on
Explain Expanding Pilot
Holds as a small flame then gets larger on a heating call
Explain Intermittent Pilot
On call and throughout ignition
Explain Interrupted pilot
On call and off after ignition
Post Aerated burners collect primary air at which point?
At the combustion point. Also called “Incinerating” burners because of this. Burns lint dust etc.
What is non-100% shut-off safety control
The main burner loses gas supply in a pilot outage but the pilot gas is not. Prohibited with LP gas
100% Safe Hook-up does what on a pilot outage?
Turns off gas suply to main burner and the pilot gas.
A thermopile is a bunch of thermocouples ties in series or in parallel?
In series
The lead of a thermocouple should not be bent closer than… from the junctions
1”
Pilot flame should evnvelope which portion of the thermocouple/pile?
Top 3/8” to 1/2”
What is a proved pilot?
A pilot flame that is supervised by a flame failure device (Thermocouple)
