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TSSA G2 FINAL EXAM 200 QUESTIONS & CORRECT
ANSWERS WITH RATIONALES ALREADY GRADED A+
NEW
On a pilot what causes a lazy yellow flame? - CORRECT ANSWER >>> Dirty lint screen Primary air opening Orifice too big Main functions of a gas regulator? - CORRECT ANSWER >>> Reduce and maintain downstream pressure.Pressure to appliance can be adjusted.Smooth and even flow. What does the measuring element do? - CORRECT ANSWER >>> Measures downstream pressure. What is the restricting element? - CORRECT ANSWER >>> Increases or decreases gas flow Loading element does what? - CORRECT ANSWER >>> set operating pressure. What is the closing force in a regulator? - CORRECT ANSWER >>> The downstream outlet gas pressure What is the function of a regulator vent? - CORRECT ANSWER >>> Allow gas to escape in case of diaphragm rupture or downstream over pressure At the leak limiting orifice how much gas is allowed to leak in a one hour period? - CORRECT ANSWER >>> 1 cu ft per hour.
Surge limiting valve are used where? - CORRECT ANSWER >>> Applications where regulators are required to be slow opening. Where is the service regulator located?And used to do what? - CORRECT ANSWER >>> At the end of the utility's pipeline. It's used to reduce supply pressure to the building pressure. Appliance regulators serve what purpose? - CORRECT ANSWER >>> The reduce the building pressure to the manifold pressure on the appliance. What is the system regulator?And what pressures does it bring it down to? - CORRECT ANSWER >>> The regulator between the service regulator and the appliance regulator.From 125 - 5 psig What does a first stage regulator do, and brings it down to what pressure? **- CORRECT ANSWER
** It reduces cylinder pressure down to supply line pressure.Reduces pressure from 250- 375 psig down to 10 psig.
Second stage regulator does what? And brings it down to what pressures? **- CORRECT ANSWER
** It reduces supply line pressure to building pressure.Pressure reduced from 10 psig down to 11" w.c. Corrugated metal gas connector, connected to a range must not exceed **- CORRECT ANSWER ** 6ft Black iron pipe 2 1/2 NPS at 150ft long shall be pressure tested to? - CORRECT ANSWER >>> 1. times the maximum operation pressure for 180 minutes A manual shut off valve shall be installed - CORRECT ANSWER >>> In either drop of riser of a ** Applications where regulators are required to be slow opening. Where is the service regulator located?And used to do what? - CORRECT ANSWER >>> At the end of the utility's pipeline. It's used to reduce supply pressure to the building pressure. Appliance regulators serve what purpose? - CORRECT ANSWER >>> The reduce the building pressure to the manifold pressure on the appliance. What is the system regulator?And what pressures does it bring it down to? - CORRECT ANSWER >>> The regulator between the service regulator and the appliance regulator.From 125 - 5 psig What does a first stage regulator do, and brings it down to what pressure? - CORRECT ANSWER >>> It reduces cylinder pressure down to supply line pressure.Reduces pressure from 250- 375 psig down to 10 psig. Second stage regulator does what? And brings it down to what pressures? - CORRECT ANSWER >>> It reduces supply line pressure to building pressure.Pressure reduced from 10 psig down to 11" w.c. Corrugated metal gas connector, connected to a range must not exceed - CORRECT ANSWER >>> 6ft Black iron pipe 2 1/2 NPS at 150ft long shall be pressure tested to? - CORRECT ANSWER >>> 1. times the maximum operation pressure for 180 minutes A manual shut off valve shall be installed - CORRECT ANSWER >>> In either drop of riser of a residential appliance
A combination fan limit control on a residential warm air furnace shuts off fan heating cycle at?
- CORRECT ANSWER >>> 90F Diode - CORRECT ANSWER >>> Only allows current to flow in one direction A heat anticipator is wired in? - CORRECT ANSWER >>> Series with the gas valve Thermocouple open test - CORRECT ANSWER >>> 25 - 30 mV Redundant gas valve - CORRECT ANSWER >>> Contains a pilot valve and a main valve A voltmeter with analog scale is to be used on a circuit of unknown voltage, the scale would be set on? - CORRECT ANSWER >>> 0 - 600V A zero reading on a voltmeter across R&C on a circuit board in a furnace would indicate? - CORRECT ANSWER >>> The fuse is burnt An aluminum 14/2 conductor, 60ft long requires a current protection of? **- CORRECT ANSWER
** 15A Electronic air cleaner (EAC) - CORRECT ANSWER >>> Has ionizing plates that are positively and negatively charged. Hearing a zapping sound means its dirty and it would produce high levels of ozone. Spalling - CORRECT ANSWER >>> Pieces of chimney flue flake and delaminate Tip over switch - CORRECT ANSWER >>> Used on construction heaters
Pressure switch - CORRECT ANSWER >>> A normally open switch Muriatic acid or pickling vinegar - CORRECT ANSWER >>> Used to descale a boiler Heating output of a boiler should? - CORRECT ANSWER >>> Exceed calculated space heating loss of the building Selecting the right circulating pump - CORRECT ANSWER >>> Size based of btu of the system. flow rate of pump should be be 1 GPM per 10,000 Btu input of the water heater Size anode should be changed - CORRECT ANSWER >>> 3/8" Size anode should be - CORRECT ANSWER >>> 3/4" Fan turns on - CORRECT ANSWER >>> 140F Fan turns off - CORRECT ANSWER >>> 90 - 100F Types of ignition - CORRECT ANSWER >>> HSI (hot surface igniter Standing pilot Spark ignition Most heat resistant vent - CORRECT ANSWER >>> Type A Fan control operation - CORRECT ANSWER >>> Line voltage 120V
Two types of thermistors - CORRECT ANSWER >>> Positive Temperature coefficient (PTC) Negative temperature coefficient (NTC) Basic Sections of a control System - CORRECT ANSWER >>> - Operating controls
- Limit and safety controllers
- Combustion safety controller
- Ignition control module Operating controllers - CORRECT ANSWER >>> These controls respond to changes in the controlled variable (temp, pressure, etc.) and make or break circuits. Examples include thermostats, aquastats and pressure controls. Limit and safety controllers - CORRECT ANSWER >>> They take the command away from the operating controls when continued operation would cause an unsafe situation. Examples include low water cut off switches, high limit aquastats, high limit pressure controls and flow switches Combustion safety controls - CORRECT ANSWER >>> It monitors the flame initiation and allows the gas to flow only if a stable flame is initiated and maintained. Examples include flame sensors and air proving switches Ignition control module - CORRECT ANSWER >>> It sequences the safe light-up of the burner system (providing the limit controls indicate a safe condition) Examples include intermittent pilot, direct spark ignition, hot surface ignition control modules and flame safeguard controls. Thermostats for millivolt circuits are specifically manufactured for ______ systems only - CORRECT ANSWER >>> 750 millivolt
Normally closed switch that controls the temperature of the water inside the boiler. If the ________ is set for 180F, the contacts will remain closed until the water reachers this temperature. At this point, the contacts open and cut off power to the main gas valve - CORRECT ANSWER >>> Operating Aquastat If you set the _________ to 3 psig, the contacts stay closed until the steam pressure reaches 3 psig. Once it has reached this pressure, the contacts open and cut off power to the main gas valve. The contacts close again when the steam pressure reduces to a different setting. - CORRECT ANSWER >>> Operating Pressure control Low gas-pressure switch - CORRECT ANSWER >>> A reverse acting (RA) in that they open if the gas pressure falls below the setpoint of the appliance pressure regulator High gas-pressure switch - CORRECT ANSWER >>> A direct acting (DA) in that they open when gas pressure exceeds the outlet pressure of the outlet pressure of the appliance regulator Flame Rectification - CORRECT ANSWER >>> Although powered by an AC source, the size difference between the burner head and the flame rod creates a pulsating current that can be read by a dc micro-ammeter Inferred flame sensor - CORRECT ANSWER >>> The main element is a lead sulfide cell that is used as an electrical switch. The lead sulfide material is in itself a semi-conductor but when exposed to inferred radiation it loses its resistance and allows free movement of electricity. When installed in the control circuit and (sighted) at the infrared part of the pilot flame, the lead sulfide cell will energize the circuit only if it detects infrared radiation, proving the pilot flame Ignition control must be heated to? - CORRECT ANSWER >>> 2200F Hot surface ignition (HSI) control module range of resistance - CORRECT ANSWER >>> 35 - 85 ohms
3 types of DC motors - CORRECT ANSWER >>> - The series
- The shunt
- The compound Start Capacitor - CORRECT ANSWER >>> Wired in series with the start winding for more starting torque. Have a voltage range of operation Run Capacitor - CORRECT ANSWER >>> Improves the running efficiency of the split phase motor. Has a positive(+) to negative range(-) Passive house - CORRECT ANSWER >>> a voluntary standard for energy efficiency in a building that reduces its ecological footprint so that it requires little energy for space heating or cooling Factors that determine building comfort - CORRECT ANSWER >>> Heat, air, moisture Factors that cause moisture flow - CORRECT ANSWER >>> - Gravity
- Capillary Reaction
- Diffusion
- Air movement Relative humidity level in a home - CORRECT ANSWER >>> 35%-50% Factors that affect flow in a building - CORRECT ANSWER >>> - Stack Effect
- Wind Effect
- Flue & Ventilation Effect
- Combined effect
Depressurization Test - CORRECT ANSWER >>> Checking to see if there is any potential for spillage for backdraft into the house & that appliance has enough combustion air. Also to see the tightness of the house. If there is potential for induced pressure. Building negative pressure can undergo 0.02 w.c or 5 pa Windward - CORRECT ANSWER >>> Positive pressure side of the building Leeward - CORRECT ANSWER >>> Negative pressure side of the building Types of building construction - CORRECT ANSWER >>> Solid Ballon frame Platform frame R-2000 home - CORRECT ANSWER >>> Tight house standard Downdraft - CORRECT ANSWER >>> A downward current or draft of air or a pressure induced backdraft Conduction - CORRECT ANSWER >>> The transfer of heat from molecule to molecule Convection - CORRECT ANSWER >>> The transfer of heat by the movement of a fluid or air flow Radiation - CORRECT ANSWER >>> The transfer of heat by electromagnetic waves Negative building pressure - CORRECT ANSWER >>> caused by insufficient supply of makeup and combustion air
Stack Effect - CORRECT ANSWER >>> The difference between indoor and outdoor creates pressure differences due to the difference in the air densities. This pressure difference causes the building to act as a large chimney. Cold air infiltrates through holes in the lower building envelope, is heated, rises then exfiltrates through the holes in the upper building envelope. Wind Effect - CORRECT ANSWER >>> Can cause a positive pressure on the windward side of the building and negative pressure on the leeward side and on the sides parallel to the wind flow. Depending on the relative airtightness of the pressurized side compared to the other sides, the building pressure may increase, decrease or vary between separated rooms When Polyethylene plastic pipe is used underground what minimum AWG gauge copper wire is taped along the piping for tracing purposes using a metal detector or radio signal? - CORRECT ANSWER >>> 16 AWG Ignition temperature of Acetylene - CORRECT ANSWER >>> 763 - 824F Unsheathed conductors should be used where? - CORRECT ANSWER >>> Outdoors and must be enclosed in liquid tight conduit A power-pile open test - CORRECT ANSWER >>> 750 - 850 mV A breaker is installed in a main panel will protect what? - CORRECT ANSWER >>> The load connected by that breaker V bevel ends at an angle of approximately? - CORRECT ANSWER >>> 37 1/2 degrees The gap (or root) opening between the two ends is evenly spaced at? **- CORRECT ANSWER
** 1/16- 1/8 inch (1.6-3.2mm) Fire watch after welding should last - CORRECT ANSWER >>> not less than 30 mins
Air changes required in a welding shop - CORRECT ANSWER >>> 4 The amount of gas that flows through a pipe increases as the: - CORRECT ANSWER >>> - Pipe diameter increases
- Pressure drop across the length of the pipe decreases
- Length of the pipe decreases
- Density of the gas decreases Pipe sizing procedure - CORRECT ANSWER >>> 1. Sketch system 2.Select a table 3.Determine code zone 4.Size Pipe sections
- Prove code zone is correct 6.Consult code table 6.23.7 - CORRECT ANSWER >>> If the piping NPS 4 or larger, and air has been used for testing, it must be first purged with carbon dioxide, nitrogen, or a mixture of these, and then purged with the gas Weight per volume (Aluminum) - CORRECT ANSWER >>> 165 Weight per volume (Concrete) - CORRECT ANSWER >>> 150 Weight per volume (Copper) - CORRECT ANSWER >>> 560 Weight per volume (Lead) - CORRECT ANSWER >>> 710
Contactor - CORRECT ANSWER >>> Similar to a relay, except that it contains large-load contacts designated to control large amounts of current The thermocouple only generates a voltage if the temperature difference between the hot and cold junctions is at least ______ - CORRECT ANSWER >>> 400F Voltage rating for thermostat - CORRECT ANSWER >>> 0 - 1.5VDC Thermocouple closed test - CORRECT ANSWER >>> 10 - 15mV Thermocouple drop test - CORRECT ANSWER >>> 2 - 4mV (90 second duration) Thermopile closed test - CORRECT ANSWER >>> Over 140mV Thermopile closed test (with load) - CORRECT ANSWER >>> 140 - 275mV Thermistor - CORRECT ANSWER >>> programable thermostat Heat anticipator - CORRECT ANSWER >>> A mechanical thermostat that controls system overshoot Pressure between 1st and 2nd regulator should be? - CORRECT ANSWER >>> Maximum 10psig Loading element - CORRECT ANSWER >>> Usually a spring
Measuring element - CORRECT ANSWER >>> Usually a diaphragm Restriction element - CORRECT ANSWER >>> An orfice and valve seat Atmospheric vent - CORRECT ANSWER >>> A vent on the atmospheric side of the diaphragm Over pressure shut off valve - CORRECT ANSWER >>> To pipe your system outside you would need Balancing Diaphragms - CORRECT ANSWER >>> Separates the lower main diaphragm area and the upper valve section. It creates a balancing and stabilization in the pressure. Lockout Pressure - CORRECT ANSWER >>> When you have an immense amount of downstream pressure moving up once youtube turn off the regulator Zero Governors - CORRECT ANSWER >>> Designed to deliver an outlet pressure equivalent to the atmospheric pressure. They are normally double-diaphragm units equipped with an 0-ring seal diaphragm (balancing diaphragm). This isolates the inlet gas pressure from the lower chamber of the main control diaphragm. Droop and offset - CORRECT ANSWER >>> The downstream pressure drop below set-point Set-point - CORRECT ANSWER >>> The desired outlet pressure Lockup - CORRECT ANSWER >>> The pressure above setpoint that is used to shut the regulator off tight Criteria to evaluate the various overpressure protection - CORRECT ANSWER >>> Continuity
The seam for gas dryer vents should be upwards and slopped towards **- CORRECT ANSWER
** Outside Warp switch - CORRECT ANSWER >>> Acts as a safety device to break the circuit to glow coil and pilot valve when one of the following malfunctions occur
- Main burner does not light at initial start up because of interrupted gas supply - Pilot fails to light
- Pilot flame is faulty and not generating enough heat to cause the pilot switch to operate Low pressure system (0.25-0.5w.c) - CORRECT ANSWER >>> Typical residential duct system 2 ton unit - CORRECT ANSWER >>> 400 cfm Single Pole Double Throw - CORRECT ANSWER >>> A thermostat with a single mercury bulb Reduces condensation - CORRECT ANSWER >>> mechanical ventilation system Centrifugal switch - CORRECT ANSWER >>> Proves a dryer motor is running 80% - CORRECT ANSWER >>> maximum filling density of a cylinder with liquid propane Ammonia & Hydrogen - CORRECT ANSWER >>> used in a absorption refrigeration cycle Testing a high limit - CORRECT ANSWER >>> disconnect circulating blower 48in - CORRECT ANSWER >>> service clearance to a boiler
Temperature decreases - CORRECT ANSWER >>> when heating output from air handler decreases 12in from floor - CORRECT ANSWER >>> Discharge piping from temperature and pressure relief valve on water heater shall not terminate more than Gurgling sound - CORRECT ANSWER >>> situation where deliming is required No less than 7ft - CORRECT ANSWER >>> vent terminating on paved sidewalk 2 sides open - CORRECT ANSWER >>> furnace terminating under a veranda should have 24 in (7.6.1) - CORRECT ANSWER >>> service clearance for furnace EAC is working correctly - CORRECT ANSWER >>> If you hear a snapping sound 5000ppm (7.23.1 c)) - CORRECT ANSWER >>> Level of carbon monoxide measured by infrared heater should be interlocked with gas valve - CORRECT ANSWER >>> If a mechanical device is used for combustion air it must be Centrifugal blower - CORRECT ANSWER >>> used on a forced warm air furnace blower current increase - CORRECT ANSWER >>> when forced warm air furnace door is removed
