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14
Selection Guidelines
Motor Specifications
Blower motor information
must be specified to select
unit. The horsepower,
voltage, phase and enclosure
availability is presented
in the table on the right. If
exhaust and supply blower
horsepower are different,
consult the CAPS program.
Minimum Circuit Amps (MCA) Calculations for ERV Units
Wheel drive, 24 volt internal control amp and standard electric preheat kW. Single or three phase ERV units
Model
Wheel Drive Amps
24v
Control
Amps
Standard Electric Preheat kW
115 208/230 460 115/1 208/1 230/1 208/3 230/3 460/3
ERV-251 0.6 0.6 NA 0.5 2.5 2.1, 4.1 2.5, 5 NA NA NA
ERV-361 NA 1.2 0.6 1 NA NA NA 4.1, 8.2, 12.3 5, 10, 15 5, 10, 15
ERV-521 NA 2.8 1.4 1 NA NA NA
8.2, 12.3,
15.5
10, 15, 19 10, 15, 20, 25, 30
ERV-581 NA 1.6 0.8 1 NA NA NA 12.3, 15.5 15, 19 15, 20, 25, 30, 38
ERV-522 NA 5.6 2.8 1 NA NA NA 15.5 19 20, 25, 30, 45
ERV-582 NA 3.2 1.6 1 NA NA NA 15.5, 24.5 19, 30 20, 38, 50
NA = not available
Model
Open TE Two Speed Open
115/1 230/1 230/460/3 230/1 230/460/3 230/1 230/460/3
ERV-251S*
1
⁄4
1
⁄4 - - - - -
ERV-251H*
1
⁄2
1
⁄2 - - - - -
ERV-361* -
1
⁄4 - 2
1
⁄4 - 2
1
⁄4 - 2
1
⁄4 - 2
1
⁄2 - 1
1
⁄2 - 1
1
⁄2
ERV-521* -
1
⁄2 - 3
1
⁄2 - 5
1
⁄2 - 1
1
⁄2
1
⁄2 - 5
1
⁄2 - 1
1
⁄2 - 3
ERV-581* - - 1 - 5 - 1 - 5 - 1 - 3
ERV-522* - 1
1
⁄2 - 3 1
1
⁄2 - 15 1
1
⁄2 1 - 15 - 1 - 7
1
⁄2
ERV-582* - - 1
1
⁄2 - 15 - 1 - 15 - 1 - 7
1
⁄2
UL Listing is available on most open drip proof motors.
*Energy wheel drive motor is only available with open drip proof motors
.
MCA Example Calculation
Greenheck ERV selected: ERV-361S-B, 2 hp
supply motor, 1
1
⁄2 hp exhaust motor, 15kW
preheater operating at 460 volt, three phase.
Step 1: Consult NEC table (not shown) for 2 hp
supply motor amps = 3.4 A
Step 2: Consult NEC table (not shown) for 1
1
⁄2 hp
exhaust motor amps = 2.6 A
Step 3: Calculate 15kW preheater amp draw =
15,000W/ [460 * 3 ] = 18.8 A
If no preheater is used skip step 3
Step 4: Wheel drive amps for ERV-361 from
table above = 0.6 A
Step 5: 24v Control Amps for ERV-361 from
table above = 1.0 A
Step 6: MCA = Amperage total from steps
1 thru 5 x 1.25
MCA = (3.4 + 2.6 + 18.8 + 0.6 + 1.0)
1.25 = 33 A
Note: Calculations are approximate, use our Computer Aided Product Selection (CAPS) program for exact
MCA calculations.
Filter Pressure Drop
Model CFM
Intake Hood
with 2-inch
aluminum
filters
Pleated
2-inch
filters
ERV-251
500 0.09 0.09
1,000 0.32 0.19
ERV-361
1,000 0.09 0.10
2,200 0.45 0.28
ERV-521
2,500 0.13 0.14
4,500 0.45 0.32
ERV-581
4,500 0.17 0.15
5,500 0.30 0.24
ERV-522
6,000 0.15 0.14
9,000 0.40 0.25
ERV-582
9,000 0.13 0.16
12,000 0.45 0.27