Chapter 38
What is the most common type of residential heating system used today?
Forced Air Heating System
True or False: A combustion-type furnace's burners and blower both turn on at the same time.
FALSE
What does PSC motor stand for?
Permanent Split Capacitor motor
What are the two primary fuel gases used on a furnace?
Natural Gas & Propane
What is a good supply and return temperature split difference on a gas furnace?
50
What are the two type of motor driven blowers?
Belt driven & Direct driven
A condensing furnace has a efficiency rating that is ___?
above 90%.
21%
True or False: Air pressure switch is a normally closed switch.
False
What is the last device or come on a furnace and the last thing to turn off on the sequence of operation on my furnace?
blower
True or False: Belt driven blowers are inherently more efficient that direct-driven blowers
FALSE.
In a condensing furnace what heat exchanger condenses?
Secondary
What does ECM motor stand for?
Electronically Commutated Motor
manometer.
How many volts powers a hot surface ignitor on a furnace?
120v
Due to system operation, a condensing furnace's exhaust piping is often made of____?
PVC
If you have a furnace that is "starving for air" you will most likely need to install at ____.
Make Up Air Unit
Furnace gas pressure is measured in___?
in WC.
Which safety switch prevents my heat exchanger from overheating?
High limit switch
True or False: High limit switches can either be manual reset or auto reset.
TRUE
Unit Heaters are ____ and used in most commonly in what areas?
ductless, large open areas.
In a condensing heat the primary heat exchanger transfers ____heat, and the secondary heat exchanger transfers ____heat.
sensible; latent
What is the main symptom of a cracked heat exchanger?
Flame Rollout
The gas supply to a gas furnace is maintained at a low pressure by the ____?
gas pressure regulator
explain the process of refrigeration
......