Thermostat; Electric Heaters - Carrier WeatherMaster Series Installation Instructions Manual

Open Controller for Building Management Systems, using
non-CCN protocols. (RTU Open controller is available as a
factory-installed option only.)

THERMOSTAT

Select a Carrier-approved accessory thermostat. When
electric heat is installed in the 50HC unit, the thermostat must
be capable of energizing the G terminal (to energize the In-
door Fan Contactor) whenever there is a space call for heat
(energizing the W1 terminal). The accessory thermostats list-
ed on the unit price pages can provide this signal but they are
not configured to enable this signal as shipped.
Install the accessory thermostat according to installation
instructions included with the accessory.
Locate the thermostat accessory on a solid wall in the con-
ditioned space to sense average temperature in accordance
with the thermostat installation instructions.
If the thermostat contains a logic circuit requiring 24-v
power, use a thermostat cable or equivalent single leads of
different colors with minimum of seven leads. If the thermo-
stat does not require a 24-v source (no "C" connection re-
quired), use a thermostat cable or equivalent with minimum
of six leads. Check the thermostat installation instructions for
additional features which might require additional conductors
in the cable.
For wire runs up to 50 ft. (15 m), use no. 18 AWG (Amer-
ican Wire Gage) insulated wire (35°C minimum). For 50 to
75 ft. (15 to 23 m), use no. 16 AWG insulated wire (35°C
minimum). For over 75 ft. (23 m), use no. 14 AWG insulated
wire (35°C minimum). All wire sizes larger than no. 18 AWG
cannot be directly connected to the thermostat and will re-
quire a junction box and splice at the thermostat.
See Fig. 30 for typical low-voltage control connections.
Typical
Thermostat
Connections
C
G
W2
(Note 2)
W1
O/B/Y2
(Note 1)
Y1
R
Note 1: Typical multi-function marking. Follow manufacturer's configuration
instructions to select Y2.
Note 2: W2 connection not required on units with single-stage heating.
Field Wiring
Fig. 30 — Typical Low-Voltage Control Connections
Central Terminal Board
The Central Terminal Board (CTB) is a pass through con-
nection point. The CTB provides the capability to add facto-
ry-installed options and field-installed accessories to the units
Central
Terminal
Board
X X
C C
G G
W2 W2
W1 W1
Y2 Y2
Y1 Y1
R
R
T–STAT
by cutting jumper wires without having to change or reroute
wires through the structure of the unit. The CTB does not pro-
vide any microprocessor control; it is simply a basic multi-
function wiring terminal configuration.
Unit without Thru-Base Connection Kit
Pass the thermostat control wires through the hole provid-
ed in the end panel (see item "D" in the view labeled "LEFT"
in Fig. 2 and Fig. 3) then feed the wires through the raceway
built into the corner post to the control box. Pull the wires
over to the terminal strip on the upper-left corner of the Cen-
tral Terminal Board (CTB) See Fig. 31.
RACEWAY
HOLE IN END PANEL (HIDDEN)
Fig. 31 — Field Control Wiring Raceway
NOTE: If thru-the-bottom connections accessory is used, refer to
the accessory installation instructions for information on routing
power and control wiring.
Heat Anticipator Settings
Set heat anticipator settings at 0.14 amp for the first stage
and 0.14 amp for second-stage heating, when available.

ELECTRIC HEATERS

The 50HC units may be equipped with factory or field-in-
stalled electric heaters. The heaters are modular in design,
with heater frames holding open coil resistance wires strung
through ceramic insulators, limit switches and one or two
control contactors. One or two heater modules may be used in
a unit.
Heater modules are installed in the compartment below the
indoor (supply) fan outlet. Access is through the indoor ac-
cess panel. Heater modules slide into the compartment on
tracks along the bottom of the heater opening. See Fig. 32-
34.
Not all available heater modules may be used in every
unit. Use only those heater modules that are UL listed for use
in a specific size unit. Refer to the label on the unit cabinet
for the list of approved heaters.
Unit heaters are marked with Heater Model Numbers, but
heaters are ordered as and shipped in cartons marked with a
corresponding heater Sales Package part number. See Table 3
for correlation between Heater Model Number and Sales
Package part number.
NOTE: The value in position 9 of the part number differs be-
tween the sales package part number (value is 1) and a bare heat-
er model number (value is 0).
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