G2 Gas Technician Module 15 B Revised Already Graded A

G2 Gas Technician Module 15 B Revised Already Graded A What are the three functions of a regulator? 1. To reduce and maintain constant downstream pressure 2. To allow pressure adjustments to the appliance 3. To provide a smoother even flow What are the three operating forces of a gas regulator? 1. Measuring element (diaphragm) 2. Restricting element (orifice) 3. Loading element (spring) What is the closing force in a regulator? Downstream gas pressure What are three functions of regulator vents? 1. Allow for displacement of air above measuring element so it can operate. 2. Allows gas to escape incase of diaphragm rupture or downstream over pressure. 3. Can have leak limiting orifice installed to allow for small discharge in case of diaphragm rupture What does a cent limiting orifice do? What is the drill size? How much gas per hour will it allow to pass? 1. Allows airflow in and out of the top of the regulator. 2. Normally #78 drill size. 3. Will allow one cubic foot per hour gas to pass?(propane) How do you mount a disc limiting orifice? Vertically mounted for proper install When do you use a surge limiting device? How does it work? Used when a regulator is required to be slow opening. Uses a ball to restrict the flow of air. What does a service regulator do? Reduces service pressure down to supply pressure. What does an appliance regulator do? Reduces supply pressure to manifold pressure Where is the system regulator located? Located between the service and appliance regulator. Also known as the low pressure regulator or zone regulator What does a first stage regulator do? Reduces tank pressure down to service pressure. (Propane) 250 psig - 10 psig What does a second stage regulator do? Reduces service pressure down to supply line pressure. (Propane) 10 psig - 11" w.c. How does a twin stage regulator work and what does it do? Has two stages of pressure regulation in one device. Reduces tank pressure to supply pressure. 250 psig - 11" w.c. What does a single stage regulator do? Reduces tank pressure to supply pressure through one orifice. In Ontario what type of regulation must be used in all permanent propane installations? Must have two-stage regulation What does a lock-off type regulator do? Where would it be used? Reduces pressure from lbs to lbs or lbs to inches. Will lock off on high or low pressure. Used where relief vents are not permitted and at gate stations. What is lock up pressure? What should this not exceed? 1. The pressure under which downstream pressure stabilizes at when burner shuts down. 2. Should not exceed operating pressure by more then 20% 8 things you must know to select a gas regulator. 1. Type of gas 2. Max and min rate of flow 3. Max and min inlet pressure 4. Outlet pressure. 5. Range of adjustment 6. Size of pipe connection 7. Type of valve seat 8. Droop What can undercut pipe threads cause in a regulator? May cause pipe to enter regulator to far and block sensing passages Can you use a leak limiting orifice on inside regulators? Yes Where would you install an appliance regulator? As close as possible to the appliance Where would you not install a regulator? In a high heat zone What is maximum first stage pressure? 10 pisg On a service regulator which way do you turn the adjustment screw to increase pressure? Turn clockwise to increase pressure. Incorrect lock up pressure caused by a plugged vent what to do? Clean or replace vent. Incorrect lock up pressure caused by diaphragm rupture how to fix? Replace regulator Incorrect lock up pressure caused by cut valve seat or worn out seat. How to fix? Replace valve seat or regulator Incorrect lock up pressure due to regulator body being twisted. How to fix? Replace regulator Sluggish regulator action caused by linkage friction Replace regulator Sluggish regulator action caused by a stiff diaphragm. Replace regulator Symptoms of incorrect lock up pressure? Pressure is to high, periodic relief valve opening, and periodic odour of gas near vent area Symptoms of a sluggish regulator? Varying pressure or pressure drop when burner fires. What are symptoms of pressure drop at other burners when main burner ignites? No gas at other burners, low fire at other burners, and pilot goes out Types of gas meters? 1. Bellows 2. Rotary-type 3. Orifice-type 4. Turbine Where would you use a bellow type gas meter? Domestic and commercial installs Where would you use rotary type gas meters? Commercial and industrial applications. What can a meter be made of? Tin, cast iron, pressed steel and aluminium What meter does not require lubrication? Bellow meter How much pressure is required to get a bellow moving? 0.5" w.c. How do you transport a meter? Upright What does the number on a gas meter indicate? Indicates btu capcity What are some uses of a gas meter? Measure consumption, test for leaks, and to measure input of an appliance. What state is propane in while under pressure in a container? Both liquid and vapour When pressure of propane changes what also changes directly? Temperature How many times will liquid propane expand when released to atmosphere? 270 times How much does one pound of liquid propane expand when converted to vapour? 8.5 cubic feet How much do you fill a propane tank? 80% What are the 2 classifications of propane containers? Tank or cylinder What is the largest cylinder manufactured? 1000 lbs What is the relief valve set at for a propane cylinder? 375 psig What is the relief valve set at for a propane tank? 250 psig What standards are propane cylinders set by? Transport Canada What standards are propane tanks set by? Boiler and pressure vessel act (ASME) What is the purpose of purging a propane cylinder? To remove H2O How is a liquid withdrawal valve threaded? Right handed Where is a liquid withdrawal valve installed? Threaded into the bottom or internally piped via a dip tube. What must a liquid withdrawal valve be equipped with? Must have an excess flow valve An excess flow valve allows liquid and vapour to flow which way? Both ways. When does an excess flow valve start controlling the flow? When it exceeds 1.5 times normal flow Where must you never store a propane container? Inside this applies to empty containers as well What is the 3 governing rules on discharge distance from a relief valve on a propane container? 1. 3 ft on a horizontal plane from any building open that is below the relief valve 2. 10 feet on a horizontal plane from an appliance air intake or air moving equipment 3. 10 feet horizontally from any ignition source What must a relief valve on a propane cylinder be protected with? A rain cap What temperatures must a propane container never be exposed to? Temps greater than 125 F When should a propane container not be filled? When it shows signs of damage, deterioration or incorrect install What happens if a regulator vent becomes blocked with the regulator in an open position? Excessive downstream pressure Who tests propane tanks? TSSA Who tests propane cylinders? Transport Canada How must meters be set when installed? Facing out from the wall with the inlet and outlet connected to supply and utility dealer piping respectively What is the name of the regulator that is found in a combination gas valve? Appliance regulator What is the purpose of a temperature compensated gas meter? Allows them to work outside at certain temp ranges What 4 things must be down when converting an appliance from natural gas to liquid petroleum? 1. Change orifice 2. Change spring 3. Adjust pressure 4. Label unit Where should propane cylinders be mounted on a recreational vehicle? To the frame What material can a vent line for a pressure regulator utilize? Steel pipe, copper, seamless aluminum or steel tubing Clause 5.5.1.a What size should a regulator vent line be? A size at least equal to the nominal pipe size Clause 5.5.1.b)