Gas Final Flashcards
How far should a swimming pool heater be from the property line?
18”
A direct vent should be how far from the regulator vent?
3’
How many supports are required on a horizontal tank?
2
What is the max pressure in a family dwelling?
2 psig
What is the max propane pressure on a commercial building?
20 psi
What type of material uses gaskets?
Neoprene
What are the joining methods for underground tubing?
- Brazing
- Flare
- Mechanical approved compression
What is the maximum metal flex connector for decorative appliances?
2’ (600mm)
What is the minimum distance for non-special vent termination?
2’
For a hot water tank with 500 BTUH, what is the air supply duct size?
None is required
What is the max setting for a high limit on a forced air furnace?
250 degrees F
On a 3000 BTUH appliance, how much air is required for combustion besides excess air and dilution air?
100 BTUH for 1 cubic foot of air
What type of pipe is not allowed on gas?
Cast iron
What is not allowed regarding piping?
- Piping going through the wall with twin joint
- Piping under foundation wall
What do you need when installing plastic pipe underground?
Tracer wire
What is the bury depth on a gas line?
15”
What is the flammability range of propane?
2.15 - 9.6%
How does the high limit operate?
On rise in temperature
What is the minimum size for the future on a gas line?
Full size if branch
What is the minimum service clearance?
24”
What is the minimum clearance of B vent?
What is the minimum clearance of C vent?
6”
Where is the relief valve on propane located?
Vapour space
Are you allowed to use plastic pipe on liquid propane?
No
What is the minimum length of a dirt pocket?
3”
What must be done in a corrosive environment?
Coated
What is the schedule on 1/2 threaded pipe?
80
What is the pressure test requirement for a gas system of 200’ and 2 psi?
15 psi for 60 min
What is the cause of a big pressure drop in a gas system?
Undersized pipes
What causes internal regulator freeze up?
High demand
What happens if the vent regulator is plugged?
Doesn’t open on call for heat
What happens when the vent is blocked on a regulator?
Sluggish operation
What does the turndown test verify?
Positioning of pilot assembly
Who is responsible to show the consumer how an appliance works?
Installer
What is the orifice size for 4” WC and 24000 BTUH with 4 burners?
27
Why do you drill orifice size two sizes smaller?
Because can drill steady enough to have perfect hole
What type of voltage is on an electromagnetic device (pilot) for forced air furnace?
Millivolts
What has the fastest response time?
Flame rod or thermocouple or thermopile or generator
What can be used on intermittent pilot?
Thermocouple or thermopile
What has the highest voltage?
Spark igniter 10-30 KV AC
Where do you take the rectification signal?
Flame signal to ground
What is the type of regulator on a propane system?
Two stage
What type of current is used on the rectification signal?
DC
What is the minimum vent height on a unit heater?
What engages the relay for the blower motor?
Thermostat
