Manual D

The basic objective of Manual D is to design a duct system that will work with the ___(Blank)___ that is supplied with the HVAC equipment. A.) BTU output B.) BTU input C.) Blower D.) Electrical circuit ampacity

C.) Blower

Excessive path (oversized ducts) CFM Problems are resolved by ___(Blank)___ in appropriate locations. A.) Installing additional elbows B.) Installing additional fittings C.) Installing and adjusting balancing dampers D.) Remove Straight run ducts

C.) Installing and adjusting balancing dampers

___(Blank)___ CFM is required for room with a 4000 BTU room load, a 1,000 blower cfm and a heating load of 30,000 BTU's. A.) 100 B.) 133 C.) 157 D.) 168

room load x blower / heating load= CFM B.) 133

___(Blank)___ CFM would be required if the Manual J heating load was 62,000 BTU's with supply air temperature of 127 degrees F and return air temperature of 70 degrees F with an altitude correction factor of 1.2 A.) 824 B.) 904 C.) 984 D.) 1084

Load/ 1.1xACFxTD A.) 824

Using the Psychometric Airflow Calculation formula of Section 1-13, ___(Blank)___ CFM would be required if the Manual J heating load was 62,000 BTU's with a supply air temperature of 127 degrees F and return air temperature of 70 degrees F with an altitude correction factor of 1.2 A.) 1050 B.) 1203 C.) 1283 D.) 1313

Load/ 1.1xACFxTD C.) 1283

What would be the sensible cooling of a system with a 1,320 CFM duct reading, a supply register temperature reading of 56 degrees F and a return grill temperature reading of 74 degrees F be? A.) 24,200 B.) 25,660 C.) 26,810 D.) 27,560

BTU=CFMxTDx1.08 B.) 25,660

A forced air furnace with a 920 CFM duct reading, a supply register temperature reading of 108 degrees F and return grille temperature reading of 68 degrees F would have a final reading of ___(Blank)___. A.) 37,248 B.) 38,822 C.) 39,744 D.) 40,256

BTU=CFMxTDx1.08 C.) 39,744

Duct sizing is not based on the amount of pressure that the blower produces but on the net pressure that is ___(Blank)___ to move the air through the circulation path that produces the most resistance to airflow. A.) Available B.) Delivered C.) Expected D.) Anticipated

A.) Available

The procedure for sizing a duct system with multiple supply and return air outlets creating multiple effective length is to size based on the ___(Blank)___ effective length value A.) Largest B.) Average C.) Return duct D.) Supply duct

A.) Largest

The airflow resistance produced by the duct system (Duct runs, fittings, and air-side-components) in terms of static pressure, shall ___(Blank)___ the external static pressure (ESP) produced by the blower package when the blower delivers the desired CFM. A.) Match B.) Be < C.) Be > D.) Double

A.) Match

Once the design value for the value for the blower CFM is known, the air flow required for each room can be estimated by ___(Blank)___ the blower CFM by the room load and then ___(Blank)___ the result by the Manual J design load A.) Multiplying, Dividing B.) Dividing, Multiplying C.) Adding, Subtracting D.) Subtracting, Adding

A.) Multiplying, Dividing

Normally the blower is a factory installed component, however, one part of Manual D is used to see if blower performance is ___(Blank)___ the airflow and pressure requirement of the proposed air distribution system. A.) Roughly compatible with B.) Quarter of C.) Third of D.) Half of

A.) Roughly compatible with

When adding a ducted return air to the system, some pressure is used to move air through the return air duct so less pressure is available for the supply side of the system. The only change in the formula to convert the system pressure drop value to a friction rate value will be the ___(Blank)___. A.) Total effective length B.) Fan Performance C.) CFM D.) Heat load

A.) Total effective length

Using the information in question 5, calculate the friction rate for a forced air furnace with a blower capacity of 1400 CFM and a pressure drop of 0.18 with a total effective length (TEL) of 280 feet of duct allowing for the additional 100 feet of return air duct. A.) 0.10 B.) 0.06 C.) 0.04 D.) 0.01

B.) 0.06

Total Effective Length (TEL) is obtained by ___(Blank)___ the straight run length and the fitting equivalent length. A.) Multiplying B.) Adding C.) Dividing D.) Subtracting

B.) Adding

To achieve the heating and cooling factors, the design loads are divided into the ___(Blank)___. A.) Room loads B.) Blower CFM C.) Total effective length D.) Friction rate

B.) Blower CFM

Friction rate duct sizing is not the only criteria to design a duct system. velocity noise also needs to be considered. in most cases duct sizing that satisfies the friction rate procedure are too small to satisfy the velocity limit therefore two sizes are created. the final design always uses the ___(Blank)___ of these two sizes A.) Average B.) Larger C.) Smaller D.) Most common available

B.) Larger

Available static pressure is the pressure that is available for the straight duct runs and fittings after it is subtracted from the eternal static pressure value from the ___(Blank)___. A.) HVAC Supply B.) OEM's blower table C.) OEM's temperature rise rating D.) Mechanical engineer

B.) OEM's blower table

A ___(Blank)___ is the pressure loss that occurs between any two points in a duct system, wheres, ___(Blank)___ is the pressure loss that occurs between two points in a duct system that are separated by a specific distance. A.) Friction rate, pressure drop B.) Pressure drop, friction rate C.) Effective length, velocity limits D.) Velocity limits, Effective length

B.) Pressure drop, Friction rate

The total pressure drop for a duct run equals the pressure loss for all ___(Blank)___ sections plus the pressure loss produced by each and every ___(Blank)___ in the duct run. A.) Straight/turn B.) Straight/fitting C.) Round/trun D.) Round/fitting

B.) Straight/fitting

With a known cooling factor or 0.050 and a room sensible load of 6,000 Btus, an estimated ___(Blank)___ CFM is known. A.) 400 B.) 350 C.) 300 D.) 250

C.) 300

Pressure drop is measured in inches of water column and friction rates are measured in inches of water column per ___(Blank)___ feet of duct A.) 200 B.) 150 C.) 100 D.) 50

C.) 100

With the friction rate known for the above duct system, using the friction rate charts in appendix 2, ___(Blank)___ round galvanized duct would be required. A.) 12" B.) 14" C.) 16" D.) 17"

C.) 16"

with the friction rate known for the above duct system, using the friction rate charts in appendix 2, ___(Blank)___ round galvanized duct would be required. A.) 22" B.) 20" C.) 18" D.) 16"

C.) 18"

The cooling factor of ___(Blank)___ would be required for a room with a cooling load of 4,000 BTU's and a required 200 CFM air flow. A.) 0.25 B.) 0.50 C.) 0.025 D.) 0.050

D.) 0.050

When considering air velocity for noise control, the maximum velocity for the supply side trunk is ___(Blank)___ fpm and ___(Blank)___ fpm for the return air trunk using rigid duct. A.) 600,700 B.) 700,600 C.) 700,900 D.) 900,700

D.) 900,700

Resistance created when air is forced through equipment or a device installed in the air stream translates to a ___(Blank)___ across the component A.) Increased static pressure B.) Increased residual pressure C.) Pressure increase D.) Pressure drop

D.) Pressure drop

The airflow rate that is required for a conditioned space depends on either the sensible cooling load or heating load and on the temperature difference (TD) between the supply air and the ___(Blank)___. A.) Ambient temperature B.) Barometric pressure C.) Thermostat setting D.) Room air

D.) Room air

Calculate the friction rate for a forced air furnace with a blower capacity of 1400 CFM and a pressure drop of 0.18 with a total effective length (TEL) of 180 feet of duct. A.) 0.18 iwc/100 B.) 0.14 iwc/100 C.) 0.12 iwc/100 D.) 0.10 iwc/100

PDx100 /TEL= FR D.) 0.10 iwc/100