313D System Installation and Startup 2

Question 1

When installing a split-system condenser outdoors, what is the minimum recommended clearance from the top of the unit to any overhead obstruction?

Accepted Answer

48 inches

Answer

12 inches

Answer

24 inches

Answer

36 inches

Question 2

During system startup, the technician measures suction pressure lower than expected and superheat higher than normal. What is the most likely cause?

Accepted Answer

Restricted liquid line filter-drier

Answer

Overcharge of refrigerant

Answer

Excessive airflow across the evaporator

Answer

Oversized metering device

Question 3

What is the purpose of installing a crankcase heater on a scroll compressor before startup?

Accepted Answer

To boil off refrigerant that has migrated into the oil

Answer

To increase discharge pressure during startup

Answer

To pre-lubricate the compressor bearings

Answer

To prevent high-pressure lockout on cold days

Question 4

When connecting refrigerant line sets, which brazing rod alloy is preferred to minimize oxidation scaling inside copper tubing?

Accepted Answer

Stay-Silv 15 with nitrogen purge

Answer

Silfos 0 without flux

Answer

Harris 56 with flux

Answer

Tin-lead solder with rosin flux

Question 5

A residential condensing unit is installed on a rooftop. Which installation precaution is most important for preventing vibration transmission to the structure?

Accepted Answer

Using rubber isolation pads or spring isolators under the unit

Answer

Securing refrigerant lines with metal clamps every 6 feet

Answer

Insulating the suction line with foam wrap

Answer

Installing a liquid line solenoid valve

Question 6

During a new installation leak check using nitrogen, at what pressure should the technician hold the system before releasing and checking for leaks?

Accepted Answer

150 psig for 24 hours

Answer

25 psig for 10 minutes

Answer

The maximum operating pressure plus 10%

Answer

Triple the low-side design pressure

Question 7

Which document must be completed and left with the homeowner after completing a new residential AC installation?

Accepted Answer

Manufacturer's warranty registration and startup checklist

Answer

EPA 608 certification copy

Answer

Technician's refrigerant purchase receipt

Answer

Local building permit application