CR-39 Part 1| Ques ons and answers | Updated RATED
A+ | 2026
Given: A 42 in x 30 in register has a velocity of 500fpm, and 75% free area. What is the CFM
capacity of this register?
3,281 CFM
3 mul ple choice op ons
CFM = FPM x Area in sq+
(42 x 30 = 1260 sq. Inches) / 144 (sq inches per sq foot) = 8.75 square feet
(8.75 x .75 (75%) + 6.5625 (free area)
6.5625 (free area sq. feet) x 500 (FPM) = 3,281 cfm
What is the max smoke devolved ra4ng of foam plas4c insula4on?
450
3 mul ple choice op ons
Refrigera4on equipment installed on a rood and or electrical outlets used for servicing roof
mounted equipment must be install a minimum of how far from the edge if no guardrail is
present?
10 +
3 mul ple choice op ons
What se8ng should the fuel gas valve be set for the boiler?
Per the manufacturer recommenda4on
3 mul ple choice op ons
What is the max distance a UV scanner can be from a flame?
18 In
3 mul ple choice op ons
The TXV or TEV ( Thermosta4c expansion valve) or metering device is located [BLANK] of a
refrigera4on system.
, between the high pressure side and the low pressure side
3 mul ple choice op ons
Copper tubing in a fuel oil system shall have [BLANK] minimum wall thickness.
0.032in
3 mul ple choice op ons
Which of the following does not have an effect on the size of the thermosta4c expansion valve?
refrigerant type
3 mul ple choice op ons
Which of the following does a star4ng relay open a+er a herme4c compressor reaches about
two-thirds of its rated speed?
start windings
3 mul ple choice op ons
When is superheat added to gas?
When suc4on gas temperature s too high or motor compressor is overheated
3 mul ple choice op ons
Embedded copper pipe shall be joined how?
Brazed
3 mul ple choice op ons
The minimum ID size for a fuel oil return is?
1/4 in.
3 mul ple choice op ons
A furnace that is installed in a residen al garage shall have the burners, fan motors and
electrical devices installed a minimum of how many inches above the floor?
18 in.
3 mul ple choice op ons
What is the minimum required size of a condensate drain pipe?
3/4 in.
A+ | 2026
Given: A 42 in x 30 in register has a velocity of 500fpm, and 75% free area. What is the CFM
capacity of this register?
3,281 CFM
3 mul ple choice op ons
CFM = FPM x Area in sq+
(42 x 30 = 1260 sq. Inches) / 144 (sq inches per sq foot) = 8.75 square feet
(8.75 x .75 (75%) + 6.5625 (free area)
6.5625 (free area sq. feet) x 500 (FPM) = 3,281 cfm
What is the max smoke devolved ra4ng of foam plas4c insula4on?
450
3 mul ple choice op ons
Refrigera4on equipment installed on a rood and or electrical outlets used for servicing roof
mounted equipment must be install a minimum of how far from the edge if no guardrail is
present?
10 +
3 mul ple choice op ons
What se8ng should the fuel gas valve be set for the boiler?
Per the manufacturer recommenda4on
3 mul ple choice op ons
What is the max distance a UV scanner can be from a flame?
18 In
3 mul ple choice op ons
The TXV or TEV ( Thermosta4c expansion valve) or metering device is located [BLANK] of a
refrigera4on system.
, between the high pressure side and the low pressure side
3 mul ple choice op ons
Copper tubing in a fuel oil system shall have [BLANK] minimum wall thickness.
0.032in
3 mul ple choice op ons
Which of the following does not have an effect on the size of the thermosta4c expansion valve?
refrigerant type
3 mul ple choice op ons
Which of the following does a star4ng relay open a+er a herme4c compressor reaches about
two-thirds of its rated speed?
start windings
3 mul ple choice op ons
When is superheat added to gas?
When suc4on gas temperature s too high or motor compressor is overheated
3 mul ple choice op ons
Embedded copper pipe shall be joined how?
Brazed
3 mul ple choice op ons
The minimum ID size for a fuel oil return is?
1/4 in.
3 mul ple choice op ons
A furnace that is installed in a residen al garage shall have the burners, fan motors and
electrical devices installed a minimum of how many inches above the floor?
18 in.
3 mul ple choice op ons
What is the minimum required size of a condensate drain pipe?
3/4 in.
