MOTORMASTER® CONTROL
(LOW AMBIENT KIT)
INSTALLATION
The accessory low-ambient kit contains a fan speed (Motor-
master) control device activated by a temperature sensor (Fig. 8).
The kit controls condenser fan motor speed in response to
the saturated condensing temperature. For outdoor tempera-
tures down to −20 F (−29 C), it maintains the condensing
temperature at 100 610 F (38 66 C).
The low-ambient (Motormaster) control consists of a solid-
state circuit on a printed circuit board encased in an alumi-
num extrusion. The control must be fastened to a panel in
the unit, and the sensor assembly (Fig. 8) mounted to a re-
turn bend on the unit’s condenser coil. Parts necessary for
mounting control and sensor are included in the kit.
Pre-Installation
DISCONNECT UNIT POWER — To prevent electric shock,
open and tag all disconnects before modifying the condens-
ing unit.
INSTALL WINTER START CONTROL — The unit must
be modified for winter start control before installing and us-
ing the low-ambient kit. Order Winter Start Control acces-
sory no. 38AE900021 and install according to the instruc-
tions supplied with the kit. See Fig. 9 for wiring.
FABRICATE AND INSTALL WIND BAFFLES — The
38AKS units equipped with the low-ambient kit require baffles
to prevent wind crosscurrents from causing abnormal opera-
tion as the fan is modulated. Construct and install wind baffles
as shown in Fig. 10.
VERIFY POWER WIRING — Power wiring must comply
with NEC (National Electrical Code) and all requirements.
Confirm that supply voltage meets minimum voltage speci-
fied on the unit’s rating plate and that it matches the voltage
rating of the low-ambient kit.
LEGEND
C—Contactor
HPS — High-Pressure Switch
IP — Internal Protector
LPS — Low-Pressure Switch
TDR — Time-Delay Relay
Field-Supplied Wiring
Fig. 9 — Connection Points, Time-Delay Relay,
Accessory Winter Start Package 38AE900021
KIT NO. VOLTS AMPS A B C
32LT900301 All except 460 8.0 5
7
⁄
8
6
3
⁄
16
3
3
⁄
8
32LT900611 460 4.0 5
7
⁄
8
7
3
⁄
8
3
3
⁄
8
Fig. 8 — Low-Ambient (Motormaster) Control and
Sensor Assembly
LOW-AMBIENT
CONTROL
SENSOR
ASSEMBLY
A
B
C
9
To Next Page
Loading...
