Set 2: Rooftop Units With Electric; Heat - Trane IntelliPak 1 Installation, Operation And Maintenance Manual

I I n n s s t t a a l l l l a a t t i i o o n n
N N o o t t e e : : If selected MOP is less than the MCA, then select
the lowest standard maximum fuse size which is
equal to or larger than the MCA, provided the
selected fuse size does not exceed 800 amps.
Set 2: Rooftop units with Electric Heat
S S i i n n g g l l e e S S o o u u r r c c e e P P o o w w e e r r u u n n i i t t s s ( ( 4 4 6 6 0 0 V V a a n n d d 5 5 7 7 5 5 V V ) )
To arrive at the correct MCA and MOP values for these
units, two sets of calculations must be performed. First
calculate the MCA and MOP values as if the unit was in
cooling mode (use the equations given in Set 1). Then
calculate the MCA and MOP values as if the unit were
in heating mode as follows. (Keep in mind when
determining LOADS that the compressors don't run
while the unit is in heating mode).
For units using heaters less than 50 kW:
MCA = 1.25 x (LOAD1 + LOAD2 + LOAD4) + (1.25 x
LOAD3)
For units using heaters equal to or greater than 50 kW:
MCA = 1.25 x (LOAD1 + LOAD2 + LOAD4) + LOAD3
The nameplate MCA value will be the larger of the
cooling mode MCA value or the heating mode MCA
value calculated above.
MOP = (2.25 x LOAD1) + LOAD2 + LOAD3 + LOAD4
The selection MOP value will be the larger of the
cooling mode MOP value or the heating mode MOP
value calculated above.
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Select a fuse rating equal to the MOP value. If the MOP
value does not equal a standard fuse size as listed in
NEC 240-6, select the next lower standard fuse rating.
N N o o t t e e : : If selected MOP is less than the MCA, then select
the lowest standard maximum fuse size which is
equal to or larger than the MCA, provided the
selected fuse size does not exceed 800 amps.
D D u u a a l l S S o o u u r r c c e e P P o o w w e e r r u u n n i i t t s s ( ( 2 2 0 0 0 0 – – 2 2 3 3 0 0 V V w w i i t t h h E E l l e e c c t t r r i i c c
H H e e a a t t ) )
These units will have two circuit values shown on the
nameplate. The first circuit value will be the
refrigeration (cooling mode) values calculated per Set
1. The second set of circuit values shown on the
nameplate will be for the electric heating circuit as
follows.
MCA = (1.25 x LOAD3)
MOP = (2.25 x LOAD3)
Select a fuse rating for the electric heating circuit that is
equal to the MOP value obtained in the equation above.
If the MOP value does not equal a standard fuse size as
listed in NEC 240-6, select the next lower standard fuse
rating (see note below for exception).
N N o o t t e e : : If the available MOP option is less than the MCA
obtained in the equation above, then reselect the
lowest standard maximum fuse size which is
equal to, or larger, than the MCA, provided the
reselected fuse size does not exceed 800 amps.
RT-SVX072A-EN