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LEFT COIL
MOTORMASTER
tt
BLOWER ACCESS
ACCESS PANEL
PANEL
COMPRESSOR
ACCESS PANEL
MODELS
A48ES-A, 48EZ-A, 48VL-A, 48VT-A
50ES-A, 50EZ-A, 48VL-A, 48VT-A
§74D--A, 674D--A, 577C--A, 677C--A
704D--A, 604D--A, 707C--A, 607C--A
PGDS, PODS, PGD4
PADS, PHD3, PAD4, PHD4
PY3G, PA3G
WPGS3, WPA3, WPH3
A11089
oS
a
Se
=S
mae
SSS
|
BeESS
SSSSSSS | 222222
SSSSSPS
SSS
Sass
SSSS8S85 | SS
aes
SSSSSSS | SSeS
See
SSSSS25 | See
ess
SSSS3SS3S3 |
SeSeess
SSSiSS3 | See
eSes
Motormaster If
SSSSSSS3 | SSS
eee
SSSSSS8 | 222222
SSQSS8SS|
Seo
SeSes
SSSSS538 | SSeeees
SSSSSS88 | Spe
aees
SSS
S|
SSeS
Ss
SSSSS838|
2BeesteZ
SSSSS323|
2eSeee=
SSSSSS8 | 222222
SSSS8S2 |
SSeS Sese
SSSSSS35) | Sree Sseesee
SSSSSS838 | 2Geeaeee
SSSSSSS | SSeeeses
SSSSSS83) | 2eeeee
SSSESS 2 |
Sree
eae
SSSSS383 | 2ereees
SSSSSSS8|
ZB2Z22Z222
SSS8 |
Sees
.
SSSSSS
ZZZE
Electrical/
SSNS
Ze
Compressor
ASS
Coil
Access
OS
Panel
Models
50ZHB, 50ZPB, PHJ3, PAJ3,
PH3Z, PA3Z, WJH3, WJA3
A11090
Fig. 2 - Access Panel and Motormaster Location
SENSOR
INTEGRAL
WIRE TIE
3/8"
HEADER TUBE,
CONDUCTIVE GREASE
OR RETURN BEND
NOTE: INSTALLED SENSOR MUST BE LEFT UNINSULATED,
Sensor Connection Detaiis
A11106
Fig. 3 - Connection Details
DESCRIPTION AND USAGE
The
Motormaster
II head pressure controller is a cycle control
device activated by a temperature sensor mounted on a header tube
of the outdoor
coil (see
Fig.
1). It is designed
to cycle
the
outdoor-fan
motors
to
maintain
the
saturated
condensing
temperature within normal operating limits of approximately 130
to 110°F
high (54°C to 43°C), 70 to 50°F
low (21 to 10°C). The
controller
maintains
working
head
pressure
at
low
ambient
temperatures down to -20°F (-29°C) when properly installed.
INSTALLATION
1. Disconnect power to unit. Install lockout tag.
2. Remove
unit
electrical,
blower
and
compressor
access
panel. (See Fig. 2.)
3. Disconnect black lead from the outdoor-fan motor (OFM)
and connect to Motormaster control (See Wiring Schematic,
Fig. 7 or 8).
4. Using a knockout punch
and die combination, make hole
in the access panel to feed MotormasterII Control wire leads
to the side of its mounting location (See Fig. 2 and Fig. 4 or
Fig. 5).
NOTE:
Field-supplied conduit must be used between controller
and access panel (or wire into unit entrance).
Created hole on the
access panel must be sealed to comply with National Electric Code
(NEC).
5. Mount Motormaster II Controller on unit. Refer to
Fig. 2
and Fig. 4 or Fig.
5, The
controller must
be mounted
vertically with the leads at the bottom. Using the Mounting
Template
(Fig.
9) as a guide,
drill mounting
holes. To
ensure electrical ground, insert star washers (supplied with
the controller) under the heads of mounting screws.
6. Determine sensor location by referring to Fig. 10-41. Route
sensor wire through bottom of Motormaster II Controller
(Fig. 1) to sensor location specified. Prior to installation,
apply conductive grease supplied with accessory to contact
surface of sensor.
4&
CAUTION
COMPONENT
DAMAGE
HAZARD
Failure to follow
this caution
may
result in component
damage.
Sensor assembly is delicate. Handle with care.
7. Attach sensor to tube as shown in Fig. 3. Installed sensor
must be left uninsulated.
8. Power
wiring
must
comply
with
all local
and National
Electrical
Code
(NEC)
and
International
Electric
Code
(IEC) requirements. Refer to Fig. 7 and 8 for power wiring
connections.
Coil up all excess wire and secure. (Yellow
and blue wires, from controller, must run to unit contactor
and connect on the load side.)
4&
CAUTION
UNIT
OPERATION
AND
COMPONENT
DAMAGE
HAZARD
Failure to follow this caution may result in improper unit
operation or component damage.
All wires must be secured so that they are not in contact
with unit tubing.
9, To prevent wind cross-currents form causing abnormally
low condensing temperatures, louvered panels are required
on some models. See Table 1 and 2 for models requiring/not
requiring louvered panels.
10. Screw back ail access panels
11. Reconnect power to the unit.
The Motormaster II head pressure controller is equipped with an
alternate
operating
mode.
When
this
mode
is
selected,
the
controller shifts the fan cycle sequence
to effectively
raise the
average condensing
temperature
approximately
20°F
(-6.7°C)
higher than the standard operating mode. In this alternate mode, the
outdoor fan begins cycling at higher outdoor ambient temperatures.
This mode should only be used if the evaporator coil shows signs
of frosting at low outdoor ambient temperatures.
To select the alternate operating mode, move the jumper wire on
the Motormaster II control board from reset T1 to T2.
Refer to Fig. 6 for thermistor resistance vs. temperature.
2
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