York R-407C Manuel D’Utilisation

YORK INTERNATIONAL

In order to use the electrical service required for the
cooling only Eco

2

 rooftop, use the appropriate calcula-

tions listed below from U.L. 1995. Based on the operat-
ing mode and configuration of the rooftop, the calcula-
tions will yield different MCA (minimum circuit ampac-
ity), and MOP (maximum overcurrent protection).

Using the following load definitions and calculations,
determine the correct electrical sizing for your unit. All
concurrent load conditions must be considered in the
calculations, and you must use the highest value for
any combination of loads.

• LOAD1 is the current of the largest motor – com-

pressor or fan motor.

• LOAD2 is the sum of the remaining motor currents

that may run concurrently with LOAD1 (i.e., exhaust
fan motor).

• LOAD3 is the current of the electric heaters – zero

for cooling only units.

• LOAD4  is the sum of any remaining currents

greater than or equal to 1.0 amp

Use the following calculations to determine MCA
and MOP for units supplied with a single-point power
connection:

MCA = (1.25 x LOAD1) + LOAD2 + LOAD4

MOP = (2.25 x LOAD1) + LOAD2 + LOAD4

If the MOP does not equal a standard current rating of
an overcurrent protective device, then the marked maxi-
mum rating is to be the next lower standard rating. How-
ever, if the device selected for MOP is less than the
MCA, then select the lowest standard maximum fuse
size greater than or equal to the MCA.

TABLE 9 – COMPRESSORS

4

SZ160

54.0

265.0

48.8

265.0

24.2

135.0

19.4

120.0

4

SZ160

54.0

265.0

48.8

265.0

24.2

135.0

19.4

120.0

4

SZ185

62.3

380.0

56.3

380.0

27.9

175.0

22.3

140.0

4

SZ185

62.3

380.0

56.3

380.0

27.9

175.0

22.3

140.0

* Values shown are per compressor