Service manual
THE SMART SOLUTION FOR ENERGY EFFICIENCY
Vertical Stack
Rev.: 11/09/12
23
climatemaster.com
Table 6 below lists recommended wire sizes and lengths
to install the thermostat. The total resistance of low-
voltage wiring must not exceed 1 ohm. Any resistance
in excess of 1 ohm may cause the control to malfunction
because of high voltage drop.
A9155 Series Thermostats have 6” pigtail ending with
9-pin Molex. This allows an easy connection to either
surface mount or remote with whip option. AT Series
Thermostats have to be wired to screw terminals under
the cover.
TRM cabinets with optional electric heat require
thermostat with minimum 2 stages of heat with
emergency heat mode, similar to ATP32U03. Stage 1 is
heat pump only. Stage 2 is heat pump with supplemental
electric heat and emergency heat is electric heat only.
Installation of Optional Wall-Mounted Thermostat -
The unit can be furnished with a 24-volt surface mounted
ACO or MCO control circuit or a remote 24-volt ACO
or MCO thermostat. A typical fi eld connection diagram
is shown in Figure 6. Refer to instructions provided with
remote thermostat for wiring instructions.
Low-voltage wiring between the unit and the wall
thermostat must comply with all applicable electrical
codes (i.e., NEC and local codes), and be completed
before the unit is installed. Use of four-wire, color-coded,
low-voltage cable is recommended.
Note: All customer-supplied wiring to be copper only,
and must conform to NEC and local electrical codes.
Wiring shown with dashed lines must be fi eld-supplied
and fi eld-installed.
UNIT
JUNCTION
BOX
A
L2
Grd
L1
R
G
Y
O
B
R
GYO
Thermostat
PDB
CXM
{
Table 6: Recommended Thermostat Wire Sizes
Legend:
A = Two power wires and ground for single-phase units.
B = Low voltage (24 vac) up to 9 wires required.
Check your thermostat.
Thermostat - 1H/1C, MCO or ACO
MCO = Manual changeover thermostat.
ACO = Automatic changeover thermostat.
WARNING! Disconnect electrical power source to prevent
injury or death from electrical shock.
CAUTION! Use copper conductors only to prevent
equipment damage
Figure 6: Typical Field Connections for units
with Wall-Mounted 24V Thermostat
WARNING!
WARNING! Zone integrity must be maintained to effi ciently
control units or groups of units. Unless zones of control are
considered and accounted for, adjacent units may operate in
heating and cooling modes simultaneously.
WIRE SIZE MAX. WIRE LENGTH
22-Gauge 30 Feet
20-Gauge 50 Feet
18-Gauge 75 Feet
16-Gauge 125 Feet
14-Gauge 200 Feet
*Physical distance from thermostat to unit
Thermostat Installation
WARNING!
CAUTION!