Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53480084-01
Printed in U.S.A.
Form 48/50A-14SI Pg 1
3-11
Replaces: 48/50A-10SI
Installation Instructions
Part Numbers: CRLOWAMB018A00 THROUGH CRLOWAMB026A00
CONTENTS
Page
GENERAL
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SAFETY CONSIDERATIONS
. . . . . . . . . . . . . . . . . . . . . . 1
INTRODUCTION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
INSTALLATION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Step 1 — Install Field-Fabricated Wind Baffles
. . . 3
Step 2 — Mounting and Electrical Connections
for Motormaster® V Control
. . . . . . . . . . . . . . . . . . . . 5
Step 3 — Configure Motormaster V Control
. . . . . 12
Step 4 — Test Motormaster V Control
. . . . . . . . . . . 12
START-UP
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-14
TROUBLESHOOTING
. . . . . . . . . . . . . . . . . . . . . . . . . .14,15
GENERAL
This book contains instructions for the installation, start-up,
and service of the Motormaster V (MMV) control on
48/50A020-060 units.
SAFETY CONSIDERATIONS
Installation, start-up, and servicing of this equipment can be
hazardous due to system pressures, electrical components, and
equipment location (roofs, elevated structures, etc.).
Only trained, qualified installers and service technicians
should install, start up, and service this equipment.
When working on this equipment, observe precautions in
the literature and on tags, stickers, and labels attached to the
equipment and any other safety precautions that may apply.
INTRODUCTION
The Motormaster V control is a motor speed control device
which adjusts condenser fan motor speed in response to varying
liquid refrigerant pressure. A properly applied Motormaster V
control extends the operating range of air-conditioning systems
and permits operation at lower outdoor ambient temperatures.
To operate these units at very low ambient temperatures,
Motormaster V controls (Fig. 1) must be added. Field-fabricated
and installed wind baffles are also required for units in areas with
prevailing winds of more than 5 mph and where temperatures
drop below 32 F. The Motormaster V control permits operation
of the unit to an ambient temperature of –20 F (–29 C). The con-
trol regulates the speed of one 3-phase fan motor (2 fans for 40 to
60 ton units) that is compatible with the control. Replacement of
fan motor on most units is not necessary since the control is com-
patible with the factory-installed fan motors. To verify that unit
fan motors are compatible with control see Table 1.
See Tables 2A-2C and 3 for the Motormaster V control acces-
sory package usage and contents. Field wiring of control is re-
quired.
WARNING
Open all remote disconnects before servicing this equip-
ment. Electrical shock could result in personal injury.
48/50A2,A3,A4,A5,AJ,AK,AW,AY020-060
Low Ambient Operation
MOTORMASTER
®
V Control Accessory
50/60 Hz
256
2
12 13A
13B
13C
1
2
3
TO MOTOR(S)
BLK
YEL
BLU
FROM FUSE BLOCK
B
TO PRESSURE
TRANSDUCER
1
2
5
6
1
12
2
14
13A
13B
13C
15
25
2
30
31
TXA
TXB
COM
+5V
TERMINAL
BLOCK
L1
L2
L3
T1 T2 T3 B- B+
PRESSURE
TRANSDUCER
Fig. 1 — Motormaster® V Control
NOTE: Wire colors for MMPT:
2 — BLACK (A)
5 — GREEN (C)
6 — RED (B)
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