Heating service exam - Michigan Questions + Answers Graded A+

______________ is to exhaust unburned gas in a combustion chamber before ignition by exhauster so the gas explodes can be prevented - Pre-purge A ______ has two or three operators physically in series but wired in parallel with one another this builtin safety feature allows any operator (pilot or main) to block - Redundant gas valve A ________ In a hydraulic piping system allows for two separate fluids at different temperatures to enter the valve and be controlled so only a single set fluid temperature leaves the valve - Diverter valve A _________ is an electrical process that causes a low level DC current to be conducted from the flame rod through the flame and back to ground - A flame Rectification system A boiler pressure relief valve that is dispensing intermittently is mostly caused by what - The expansion tank being waterlogged A fast acting type of gas valve is the _________ valve ? - Solenoid A few oil furnace in a commercial application operator the range of what psi - 100-300 psi A gas drip leg must ? - Not be smaller in diameter than the pipe which it connects A gas fired boiler with a BTU rating of 150,000 BTU requires what per CSD-1 section CW-410 - The limit to be 150,000 BTUs with a manual reset A gas fired furnace with a 6 inch common vent can have what other type of exhaust or vent listed below connected to vent - No other exhaust may be connected A gas space heater that operates with no external power source would be operating on - MillivoltsA hand shut off valve in a gas line is used to turn gas on and off to - A burner and pilot A limit control is located where in the electrical circuit - Either the 24 or 120 V circuit A oil furnace ignition transformer takes 120 V AC in transform into ________ to ignite the oil droplets - 10,000 V AC A oil furnace in a residential application operates in the range of what psi - 100-150 psi A psychrometer meter is what ? - A Hygrometer consisting of a wet-bulb and dry-bulb Thermometer, The difference in the two readings used to determine the atmospheric humidity A psychrometric chart is a - Chart where the various property of air is plotted A thermostat that cycles too often or not enough indicates - Improper heat anticipator setting A U-shaped tube partially filled with liquid and constructed so that the amount of displacement of the liquid indicates the pressure being exerted on the instrument is an - Manometer A yellow flame in a gas burner indicates - Poor air fuel mixture All boilers shall have the portable water protected with - A backflow preventer All steam boilers must have what - Quick shut off blowout valve, water glass gauges/pressure gauges, controls and limit device required by ASHRE and CSD-1 CGV is the abbreviation for - Combustion gas valveCold air return in bathroom should be ? - omitted Combustion is what type of process - chemical Compared to national gas with the same BTU rating, the orifice opening in an LP gas fire furnace is ? - Smaller Correct pitch for a steam boiler horizontal supply mains and dry returns must be _________ minimum in 10 feet of pipe in the direction of the steam condensate flow - 1/4" Ducks shall be supported at intervals of ? - In accordance with SMACANA HVAC duct construction standards - metal and flexible How much maximum play is allowed in the blower belt of a forced air furnace - 2 inches I need gravity warm air furnace, the limit control setting should not exceed - 250 degrees If too much primary air is used the flame will - Lift off the burner In a steam boiler system with a no heat call, if the steam supply line is Hot and return pipe is cold, the most likely cause would be - Air trapped in system In gas heating a standing pilot burns _________ ? - Consistently In maintaining a forced warm air furnace what is the minimum number of times the blower and electric motor bearing should be oiled - Once each heating season In order for oil to burn air passes through a nozzle to - Be atomized