Gas Heat Review
What are the by product of incomplete combustion
carbon monoxide, aldgehydes, soot
What position should the gas valve be adjust to increase and decrease?
clock wise= off counter clock wise= on
whats the manifold on the assembly for?
supplies the fuel
what is the minmeter for
test Pressure
What is the pilot safe switch for?(module)
to prove there is a flame
What can affect the temperature of gas flame according to the module?
type of fuel and amount of premix air
what position on the gas manual determine if the valve is close or open
when the valve line up with the pipe= open when the valve is crossed= close
What can cause lifting flame?
- Any gas-air change which increases burning speed -Increasing primary air
Why gas have a smell?
Add a odor to be detectable
What can affect flame sustainability on a combustion burner?
Lack of air and restriction
What are the 3 type of field gas use on gas furnace according to the module
Propane Methane Butane
Define stand pilot(module)
The main burner required the pilot(stay lit all time)
What is the typical LP manifold pressure
10.5 to 11 in W.C
How do you determine a good thermal couple on a close check?
15 mv
How much W.C per 1 IB of gas?
27.68
What is the typical natural gas manifold pressure
3.5 in W.C
How do you determine a good thermal couple on a open check?
30 mv
2 IB of gas coming into a build, how much of water is coming?
55.36 W.C
Whats the typical gas pressure coming to a build on low pressure?
7 inch W.C
What does 100% shut off on combination gas valve mean?
All of the gas on both the pilot and the main burner is automatically shut off if the pilot goes out.
Define redundant automatic gas valve?
An automatic gas valve that employs two or more valves in series, so that if one should fail to close properly, the closure of the other(s) would insure that the flow of gas is stopped. a safety requirement
What color should the flame look like?
Blue
Define Primary air
Combustion air that is mixed with gas in a Bunsen-type burner before leaving the port
Define secondary air
Combustion air that mixes with the burning gas-primary air mixture in the flame zone
Define Stoichiometric combustion?
Combustion in which the amount of combustion air supplied exactly matches the amount needed for complex oxidation of all the gas; combustion with no excess air
What can cause a flash back on gas burner
Fast burning gas primary air increase gas pressure is low
what is necessary for combustion to happen?
Fuel, air, and ignition
what can cause yellow tipping?
Lacking of primacy air supplied.
what happen if we have contamination with combustion air with chlorine compound?
Produce Hydrochloric acid, hydrofluoric acid, chlorine gas and Phosgene
Purpose of high limit
Protect heat exchanger + equipment from excessive heat + shut off the gas to prevent a fire
Define Specific Gravity(field gas)
The energy of molecular motion; measured with a thermometer;associated with a change in temperature.
Define inres (module) Pilot burner
The one has primary air thats feed in the side
Definition of flammability limits
When fuel gas and air is supplied at proper rate to assure complete of gas combustion
What can cause incomplete combustion?
lack of oxygen and impingement
What cause a flowing flame?
lack of secondary air
Purpose of gas orifice
meter the correct amount of gas into each burner
What Kind of gas burner are used on residential
mono port + multi port burner
What happen to the nitrogen in combustion process?
nitrogen then carbon dioxide then carbon monoxide
