What is the purpose of the roll-out switches?
A) to shut the gas valve off if flames roll out of the combustion area
B) to shut of the gas valve if the flames do not light within a few seconds
C) to shut off the gas valve if the air leaving the furnace becomes too hot
D) to coordinate the fan operation with the normal flame rollout on the furnace
Question 2
How is a concentric vent used in a high-efficiency furnace?
A) It creates two close exit points for the vent pipe and combustion air pipe.
B) It allows the vent pipe to combine with condensate drainage.
C) It directs the combustion air pipe to an outdoor exit.
D) It allows a single outdoor exit point for the vent and combustion air pipe.
Superior view of heart valves illustrating position, size, and shape of each valve.
(a) Homologous traits are similar due to shared ancestry. (b) Analogous traits (bats’, birds’, and f
The pressure valve maintains the system pressure and allows excess pressure to vent. The vacuum ...
A blow-off valve is used in some turbocharged systems to relieve boost pressure during ...
A steady but low reading could indicate retarded valve or ignition timing.
Apply light tapotement on the head. Tapping lightly with the fingertips works well for this purpose.