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C20 TEST 4 EXAM 2024 WITH 100% ACCURATE SOLUTIONS
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When you replace a capacitor, the replacement can be ______ the rating of the current capacitor. 10% under 10% over 15% over 20% over - ANSWER ☑☑10 % over How many acres of flooded land would be considered a flood? 1/2 acre 1 acre 2 acres 3 acres - ANSWER ☑☑2 acres What is the minimum overlap for aluminum tape? 2" 1" 3/4" 1/2" - ANSWER ☑☑1" Which of the following is not a type of compressor? crew
combustion scroll centrifugal - ANSWER ☑☑combustion When do you change the oil in a compressor? after 6 months after 1 year every 2-3 years when it is dirty - ANSWER ☑☑when it is dirty Which of the following would you switch to reverse a three-phase motor? L1 and L T1 and T T1 and L T4 and L2 - ANSWER ☑☑T1 and T Which government agency accepts reclaimed refrigerants and under which code? ARI 700 EPA 608 DSA 509 OSHA 302 - ANSWER ☑☑EPA 608 Which of the following is function of a draft diverter? llow sufficient down drafts prevent excessive down drafts
use an ohmmeter - ANSWER ☑☑shut off the condenser fan What is the EPA minimum requirement when removing Freon from a system? recycle it reclaim it recover it purge it - ANSWER ☑☑recover it What type of expansion valve is used in a high efficiency coil? automatic expansion valve (AXV or AEV) thermostatic expansion valve (TXV or TEV) thermal-electric expansion valve (THEXV) capillary tube - ANSWER ☑☑thermostatic expansion valve (TXV or TEV) A hermetic compressor is running and stable. What is the maximum amount of oil that should be in the sight glass? none 1/2 full 2/3 full 3/4 full - ANSWER ☑☑1/2 full Question 16: What kind of metal can be used for ductwork? galvanized steel stainless steel
aluminum all of the above - ANSWER ☑☑all of the above When can a fireplace be installed in a bedroom? when it obtains combustion air from outside when the homeowner wants it if it is not wood-burning never - ANSWER ☑☑when it obtains combustion air from outside What size condensate drip pan would you use for a horizontal condensing unit? 1" tall and the same length as the unit 1" tall and 3" longer than the unit 3" tall and the same length as the unit 3" tall and 3" longer than the unit - ANSWER ☑☑3" tall and 3" longer than the unit How are capacitors rated? microfarads and VAC amps and VAC microfarads and amps HP and VAC - ANSWER ☑☑microfarads and VAC If the condenser of an AC unit is installed on the roof and the coil is located a floor below, for which line must a trap be installed? iquid line suction line
What should you do if you find asbestos while working? stop working and call Cal/OSHA stop working and call the fire department stop working and go home stop working and call the superintendent - ANSWER ☑☑stop working and call Cal/OSHA Who conducts the final inspection of the installation? - ANSWER ☑☑local authority What is the maximum tonnage for units with a 3/4-inch diameter condensate drain? - ANSWER ☑☑ 20 tons What is the minimum size opening to HVAC area? 22" x 30" 24" x 30" 30" x 30" 50" x 50" - ANSWER ☑☑24" x 30" A DX coil is: direct access direct expansion drop excess drop expansion - ANSWER ☑☑direct expansion What happens when you increase the motor shaft pulley? RPMs increase
RPMs decrease belt will sag nothing - ANSWER ☑☑RPMs increase What should you do if you are soldering in an enclosed space? wear a respirator open the door wear a dust mask never solder in an enclosed space - ANSWER ☑☑wear a respirator What is the minimum slope for a condensate drain? 1/2 in/ft 1/4 in/ft 1/8 in/ft 3/16 in/ft - ANSWER ☑☑1/8 in/ft A log must be kept for equipment with _______ of refrigerant or more. - ANSWER ☑☑50 lb What would you use to solder ducts on a roof? soldering gun propane gas torch cutting torch any of the above - ANSWER ☑☑propane gas torch What is the maximum length of a clothes dryer duct? - ANSWER ☑☑14ft
1/2 sq in for every 1000 btu/h 1 sq in for every 1000 btu/h 2 sq in for every 1000 btu/h 3 sq in for every 1000 btu/h - ANSWER ☑☑2 sq in for every 1000 btu/h Where should an HVAC system be installed? in an open area in a closed room away from areas subject to mechanical damage on the roof - ANSWER ☑☑away from areas subject to mechanical damage When pressure is applied to refrigerant: the temperature increases the temperature decreases the volume increases it lowers the boiling point - ANSWER ☑☑the temperature increases What is the longest length gas flex allowed? 18 inches 24 inches 36 inches 48 inches - ANSWER ☑☑36 inches How does a heat anticipator work? turns the furnace on when it reaches the pre-set temperature
turns the furnace off when it reaches the pre-set temperature simultaneously turns on the heating element and the fan turns the furnace off before it reaches the pre-set temperature - ANSWER ☑☑turns the furnace off before it reaches the pre-set temperature What is the maximum height at which thermostat should be installed in a commercial building? 44" 48" 54" 60" - ANSWER ☑☑48" Dividers are used for: drawing a straight line reducing duct diameter drawing a circle cutting metal - ANSWER ☑☑drawing a circle A fire damper passing through a 2-hour fire wall must have a fire-protection rating of: 30 minutes 1 hour 1 hour, 30 minutes 2 hours - ANSWER ☑☑1 hour, 30 minutes What is the function of a vacuum pump? to remove air from the system
on the discharge line at the condenser outlet at the expansion valve outlet - ANSWER ☑☑at the condenser outlet What can empty disposable refrigerant cylinders be used for? nothing recovering the same type of refrigerant recovering any type of refrigerant storing contaminated refrigerant - ANSWER ☑☑nothing An extension ladder is 22' long when fully extended. How much should the two sections overlap? 1 ft 2 ft 3 ft 4 ft - ANSWER ☑☑3 ft What does a pumpdown cycle do? removes excess water removes refrigerant from the low pressure side removes oil from the refrigerant lines slows the motor - ANSWER ☑☑removes refrigerant from the low pressure side How much current is needed for a 200W/120V crankcase heater? 0.6 amps 1.2 amps
1.67 amps 3.34amps - ANSWER ☑☑1.67 amps What size wire should be used for a 25-amp circuit? 8 AWG copper 10 AWG copper 12 AWG copper 14 AWG copper - ANSWER ☑☑12 AWG copper What is the minimum gage metal duct passing through a fire wall that does not require a fire damper? 28 ga 26 ga 24 ga 20 ga - ANSWER ☑☑26 ga HVAC scroll compressors: can rotate both directions are designed to rotate in only one direction are part of a reciprocating compressor there is no such thing - ANSWER ☑☑are designed to rotate in only one direction Where do you not drain condensate? dry well floor drain dry vent
What should be placed on the main switch when servicing a unit? caution tape screen off the box a lock a note - ANSWER ☑☑a lock Which of the following is approved by the EPA? Recycle and Recover Recover and Reuse Reuse and Recycle Recover and Purge - ANSWER ☑☑Recycle and Recover What is the temperature setting for a high-limit switch on a gas furnace? 200°F 250°F 300°F 375°F - ANSWER ☑☑ 250 °F Which of the following refrigerant safety classifications is the most flammable? class A class A class A class B1 - ANSWER ☑☑class A
What should you do with an extension ladder on a windy day? never use a ladder on a windy day tie at the roof use to 1/2 extension use to 1/4 extension - ANSWER ☑☑tie at the roof What do you do with an empty disposable cylinder? recycle the metal reuse it send it back to the manufacturer store it for 6 months then send it to the landfill - ANSWER ☑☑recycle the metal What kind of pilot comes on when heat is called for, and goes off when the heating is turned off? interrupted intermittent standing blocked - ANSWER ☑☑intermittent What is the specific heat of water? 1
5 8.33 - ANSWER ☑☑ 1 What do you use to connect a branch duct to the plenum?
What happens to a heat pump if there is a sudden spike in power? alarms will go off it will run hotter it will run in reverse it will shut off - ANSWER ☑☑it will shut off Bare copper wire in an air-conditioning circuit is: ground power lead neutral not used - ANSWER ☑☑ground On a heat pump, which wire should be fused? ground line side neutral side load side - ANSWER ☑☑load side Refrigerant should be added to: low side high side line set none of the above - ANSWER ☑☑low side What is the minimum height above the bottom of a furnace that a type BW vent may terminate?
6 ft 10 ft 12 ft 18 ft - ANSWER ☑☑12 ft How many rpms is a 240V electric motor with 4 poles at 60 cycles? - ANSWER ☑☑You have to divide the number of current changes per minute by the number of stator poles to find the rpm of an electric motor. 2 changes/cycle x 60 cycles/sec = 120 changes/sec. 120 changes/sec x 60 sec/min = 7200 changes/min. 7200 ÷ 4 = 1800 rpm. What is the term for using the system condenser to store refrigerant? circulation evaporation pump down recycling - ANSWER ☑☑pump down How are fuses rated? amps and ohms amps and volts amps and watts volts and ohms - ANSWER ☑☑amps and volts What is the minimum amount of make-up air required for a room containing a commercial exhaust hood? half the amount exhausted the same amount as exhausted
