CHAPTER 10 IN NORA BOOK
QUESTIONS WITH CORRECT
ANSWERS
What is the purpose of the primary safety control? - ANS ✔✔To shut down the oil burner in the
event of a flame failure/ It also keeps the oil burner running and the oil flowing when it senses
the "PRESENCE" OF FLAME.
The primary safety control must? - ANS ✔✔React to the "presence" or "absence" of flame.
Types of primary safety controls: - ANS ✔✔- Thermal
- Visual
Stack switch- - ANS ✔✔(Thermal primary safety control) This is the ONLY primary control that
operates thermally.
A stack switch has a safety lock-out time of? - ANS ✔✔90 seconds
Stack switches are wired... - ANS ✔✔"NON-RIGID" for removal during inspection and cleaning.
(You should not have to disconnect the electrical wiring to remove it)
To place the stack switch "IN-STEP" means? - ANS ✔✔To reset the hot and cold contacts by
pulling the lever at the top of the control outward and releasing slowly.
What should you use to clean the contacts? - ANS ✔✔Never use any abrasive files or anything
similar to clean the contacts. Use somthing like a business car to clean the contacts. Place a
vacuum hose over the Bi-Metal helix to remove soot build-up from the helix.
, Scavenger time- - ANS ✔✔Is the amount of time it takes to remove the products of combustion
from the heat exchanger.
How to test scavenger time- - ANS ✔✔Run the system for 5 minutes, shut down the service
switch, when the flame goes out, turn the service switchback on and time how long it takes for
the stack switch to restart the burner.
A stack switch can be wired for... - ANS ✔✔Interrupted ignition or intermittent ignition
What is the operating range of a stack switch? - ANS ✔✔Approx. 400-900 degrees.
What is the lowest operating temperature of a stack switch? - ANS ✔✔300 degrees (this will
cause lockouts)
Where should the stack switch be mounted? - ANS ✔✔The stack switch should be mounted in
the flue pipe 12- 18 inches before the barometric draft regulator.
When wiring a 2 wire thermostat to a primary control with 3 thermostat terminals (R-W-B)
which terminals should you use? - ANS ✔✔Terminals W and B
CAD-CELL Primary safety controls: - ANS ✔✔Operates on resistance to light
The cad cell eyes is also known as... - ANS ✔✔Cadmium Sulfide Cell
The cad cell eye is? - ANS ✔✔A resistor that reacts to light. When the light it sees from the
flame gets "brighter" the electrical resistance through the eye decreases.
QUESTIONS WITH CORRECT
ANSWERS
What is the purpose of the primary safety control? - ANS ✔✔To shut down the oil burner in the
event of a flame failure/ It also keeps the oil burner running and the oil flowing when it senses
the "PRESENCE" OF FLAME.
The primary safety control must? - ANS ✔✔React to the "presence" or "absence" of flame.
Types of primary safety controls: - ANS ✔✔- Thermal
- Visual
Stack switch- - ANS ✔✔(Thermal primary safety control) This is the ONLY primary control that
operates thermally.
A stack switch has a safety lock-out time of? - ANS ✔✔90 seconds
Stack switches are wired... - ANS ✔✔"NON-RIGID" for removal during inspection and cleaning.
(You should not have to disconnect the electrical wiring to remove it)
To place the stack switch "IN-STEP" means? - ANS ✔✔To reset the hot and cold contacts by
pulling the lever at the top of the control outward and releasing slowly.
What should you use to clean the contacts? - ANS ✔✔Never use any abrasive files or anything
similar to clean the contacts. Use somthing like a business car to clean the contacts. Place a
vacuum hose over the Bi-Metal helix to remove soot build-up from the helix.
, Scavenger time- - ANS ✔✔Is the amount of time it takes to remove the products of combustion
from the heat exchanger.
How to test scavenger time- - ANS ✔✔Run the system for 5 minutes, shut down the service
switch, when the flame goes out, turn the service switchback on and time how long it takes for
the stack switch to restart the burner.
A stack switch can be wired for... - ANS ✔✔Interrupted ignition or intermittent ignition
What is the operating range of a stack switch? - ANS ✔✔Approx. 400-900 degrees.
What is the lowest operating temperature of a stack switch? - ANS ✔✔300 degrees (this will
cause lockouts)
Where should the stack switch be mounted? - ANS ✔✔The stack switch should be mounted in
the flue pipe 12- 18 inches before the barometric draft regulator.
When wiring a 2 wire thermostat to a primary control with 3 thermostat terminals (R-W-B)
which terminals should you use? - ANS ✔✔Terminals W and B
CAD-CELL Primary safety controls: - ANS ✔✔Operates on resistance to light
The cad cell eyes is also known as... - ANS ✔✔Cadmium Sulfide Cell
The cad cell eye is? - ANS ✔✔A resistor that reacts to light. When the light it sees from the
flame gets "brighter" the electrical resistance through the eye decreases.
