HVAC Apprenticeship Practice Exam
The main purpose of the accumulator is to: - ANS-Prevent liquid slugs at the compressor
Heat that changes the physical state of a substance without effecting a change in its
temperature is known as: - ANS-Latent heat
The location of the thermal bulb for the TXV on the evaporator affects: - ANS-The amount of
liquid in the evaporator
If the spring is adjusted to increase the superheat, this new setting will: - ANS-Shorten the frost
line
The amount of heat required to raise the temperature of 1 lb of water 1°F is: - ANS-1 Therm
The low pressure oil safety switch: - ANS-Must be reset manually
Suction line oil traps should be installed when the condenser is: - ANS-On the third floor roof
and the evaporator is in the basement
The proper location for an oil separator is between the: - ANS-compressor and condenser
On a TXV, the purpose of an external equalizer is to: - ANS-Compensate for a pressure drop
across the evaporator coil
The approximate boiling point of R-12 at atmospheric pressure at sea level is: - ANS--21°F
The freezing point of water is - ANS-32°F
Crankcase heaters are energized - ANS-When the compressor is of
An accumulator can be located between the - ANS-Evaporator and compressor
On a central air conditioning system, a frosted suction line at the compressor inlet
indicates - ANS-Low back pressure
The normal temperature of the liquid in an air conditioning evaporator is - ANS-35 to 40°F
In an A/C unit, dirty air filters will cause - ANS-Low suction pressure
The reversing valve is commonly used - ANS-On all heat pumps
, If the suction pressure is low and the evaporator temperature high, the cause will be a -
ANS-Starved evaporator
A gage commonly used to measure the pressure in a system while it is being dehydrated is the -
ANS-Micron millimeter gage
When an A/C system is excessively low on refrigerant - ANS-It can become contaminated with
water
There can be nuisance trip outs
The suction line may be too hot to touch
[ALL OF THE ABOVE]
When an A/C system is excessively low on refrigerant - ANS-Low on refrigerant
Dirty air filter
[BOTH A & B]
While the system is operating, the discharge line should be - ANS-At the same temperature as
the crankcase
The most common method used to determine superheat is accomplished by - ANS-Using the
suction gage and a pressure temperature chart and taking a thermometer reading under the
suction line insulation near the gage port
The biggest problem caused by moisture in the refrigeration system is - ANS-Burned out
compressor motors
When used as a drier in the liquid line, silica gel - ANS-Dehydrates water
When is a condensate trap not required - ANS-When the condensate drain is on the discharge
side of the blower
An instrument used to indicate humidity conditions is a - ANS-Hygrometer
Excessive head pressure is often caused by - ANS-Air cooled condenser is plugged
What is the suction gas temperature of R-22 if the pressure is measured as 68 psig - ANS-40°F
With a 5/8" x 5/8" x ¾" tee, what size is the center connection - ANS-¾"
Why is the suction line insulated - ANS-To prevent excessive heat gain
To prevent water damage from condensate on line
[BOTH A & B]
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller ACTUALSTUDY. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £6.47. You're not tied to anything after your purchase.
