10
48/50A2,A3,A4,A5060 MCHX UNITS — Two Motormas-
ter
®
controls are used to control two independent outdoor-fan
motors. The refrigerant circuit A Motormaster controlled OFM
is the no. 3 OFM. The refrigerant circuit B Motormaster con-
trolled OFM is the no. 1 OFM (see Fig. 3). The no. 2 and 4
OFMs are controlled to shutoff at 55 F and on at 65 F outdoor-
air temperature. All OFMs in this unit are compatible with the
Motormaster control and do NOT need to be changed out.
Use the following procedure to mount and connect the
MMV controllers to this unit:
1. Disconnect power to the unit. Lockout and tag power dis-
connect.
2. Remove control box covers.
3. Mount accessory fuse blocks HY11UT035 (label 1 as
MMF-A and the other as MMF-B) and fan relay bases
HN79KK035 (label 1 as FR-A and the other as FR-B) in-
side control box as shown in Fig. 4. Secure components
with ½-in. sheet metal screws.
a. Insert fuses into fuse blocks and relays into relay
bases.
b. Install harnesses 48EJ402454 from load side of
CCB (control circuit breaker terminals 21, 22, 23)
to line side of MMF-A and MMF-B fuse blocks as
shown in Fig. 10. Note that it may be easier to pick
up the load side of CCB (control circuit breaker)
from the ¼-in. male quick connect terminals on the
line side (terminals 11, 12, 13) of the OFCs (out-
door fan contactors). See power schematic on con-
trol box door.
c. Connect FR-A coil to OFC3 coil and FR-B coil to
OFC1 coil using the 72 in. long 16 gage white and
gray wires (stripped end goes to FR) as shown in
Fig. 10.
4. Mount the MMV controller enclosures 30RA500381on
the inside of the unit corner post, as shown in Fig. 11, us-
ing the mounting brackets 50EJ500656 installed on the
enclosures (label 1 as MMV-A and the other as MMV-B).
Remove the enclosure covers and install the ½-in.
HW60EA001 and 1-in. HW60HH006 connectors in the
holes in the lower right hand side of the enclosures.
5. Connect transducers HK05ZZ001 to the liquid line ser-
vice Schrader ports, located under the V-coil of the con-
denser fan sections, of refrigerant circuit A and B. Circuit
A is the one closest to the indoor fan motor section, and
circuit B is the one closest to the control box, (label cir-
cuit A transducer as MMPT-A and circuit B transducer as
MMPT-B).
6. Plug transducer cables 48EJ403240 into transducers (la-
bel stripped end of circuit A cable as MMPT-A and the
stripped end of circuit B cable as MMPT-B). Run cables
along inside of unit base rail and up the corner post to the
MMV enclosures.
7. Run MMPT-A cable through ½-in. connector of MMV-A
enclosure, and MMPT-B cable through ½-in. connector
of MMV-B enclosure (do not tighten connector screws at
this time). Connect red, green, and black wires to MMV-
A and MMV-B terminals 6, 5, and 2 as shown in Fig. 10.
Terminate drain wire of transducer cables under one of
the lower MMV mounting screws.
8. Make remaining electrical connections to MMV-A and
MMV-B (see Fig. 10).
a. In main control box, disconnect black, red, blue,
and green wires from load side (terminals 21, 22,
23) of OFC1 and OFC3 contactors (label cable
from OFC1 as OFM1 and cable from OFC3 as
OFM3). Pull wires out through the hole in the bot-
tom of the control box and run them through the
opening of the cable tray on the back of the control
box (where existing transducer cables come out).
Route wires along bottom edge of back of control
box and up the corner post to the MMV enclosures.
b. Run the OFM1 cable through the 1-in. connector
of the MMV-B enclosure (do not tighten connector
screws at this time). Remove ring terminals from
black, red, and blue wires and strip insulation back
3/8-inch. Connect black, red, and blue wires to
MMV-B terminals T1, T2, and T3. Connect green
ground wire to MMV-B ground screw.
c. Run OFM3 cable through 1-in. connector of
MMV-A enclosure (do not tighten connector
screws at this time). Remove ring terminals from
black, red, and blue wires and strip insulation back
3/8-inch. Connect black, red, and blue wires to
MMV-A terminals T1, T2, and T3. Connect green
ground wire to MMV-B ground screw.
d. In main control box connect 1 Motormaster® VFD
harness 50EJ400657 to the load side of MMF-A
(label the opposite end of this harness as MMF-A)
and the other Motormaster VFD harnesses
50EJ400657 to the load side of MMF-B (label the
opposite end of this harness as MMF-B). Run the
harnesses along the bottom of the control box and
out through the hole that the OFM harnesses were
in. Pull the harnesses out through the hole in the
bottom of the control box and run them through the
opening of the cable tray on the back of the control
box (in the same manner as the OFM harnesses).
e. Run the MMF-A cable through 1-in connector of
MMV-A enclosure (do not tighten connector
screws at this time). Connect L1, L2, and L3 wires
to MMV-A terminals L1, L2, and L3. Connect
green ground wire to MMV-A ground screw. Place
one large varnish cloth 48DA510141 around both
cables at the point they enter the 1-in. connector.
Tighten down connector screws being careful not
to damage the cables.
f. Run the MMF-B cable through 1-in. connector of
MMV-B enclosure (do not tighten connector
screws at this time). Connect L1, L2, and L3 wires
to MMV-B terminals L1, L2, and L3. Connect
green ground wire to MMV-B ground screw. Place
the other large varnish cloth 48DA510141 around
both cables at the point they enter the 1-in. connec-
tor. Tighten down connector screws being careful
not to damage the cables.
g. In main control box connect 1 Motormaster VFD
(variable frequency drive) harness 50EJ400658 to
the N.O. (normally open) contact of FR-A (see
Fig. 11) (label the opposite end of this harness as
FR-A) and the other Motormaster VFD harness
50EJ400658 to the N.O. contact of FR-B (label the
opposite end of this harness as FR-B) Run the har-
nesses along the bottom of the control box and out
through the hole that the OFM harnesses were in.
Pull the harnesses out through the hole in the bot-
tom of the control box and run them through the
opening of the cable tray on the back of the control
box (in the same manner as the OFM harnesses).
h. Run the FR-A cable through the 1/2-in. connector
of the MMV-A enclosure (do not tighten connector
screws at this time). Connect black wire to MMV-
A terminal 2 and red wire to MMV-A terminal 1,
13A, or 13C (see Table 4). Place 1 small varnish
cloth 38C24601 around both cables at the point
they enter the 1/2-in. connector. Tighten down con-
nector screws being careful not to damage the
cables.
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