Installation Instructions

ManualsBrandsGoodman ManualsAir Handlers4 - 5 Ton , Multi-Speed Modular Blower

cal tape. (Insulated crimp type connectors, field supplied, may

be substituted for the wire nuts and electrical tape provided

proper size connectors are used.) A ground wire MUST be

connected to the ground lug inside the unit.

LOW VOLTAGE WIRING

Low voltage wiring connections are made at the top of the cabi-

net. See the “Thermostat Wiring” section of this manual for

typical low voltage wiring connections. A minimum 18 AWG

wire must be used for installations up to 50 feet and 16 AWG

wire for installations over 50 feet.

MISCELLANEOUS ELECTRICAL

The unit transformer is factory connected for 240 V operation.

If unit is to operate on 208 V, disconnect the red wires from

terminal 3 of the unit transformer and connect them to terminal

2 of the unit transformer.

INSTALLER: It is important to follow these instructions when

installing the MB series of air handlers.

THERMOSTAT CONNECTIONS

The following composite wiring diagrams detail various con-

figurations in which your MB air handler can be used. Examples

include single stage cooling, two stage cooling and heat pump

with single or two stage electric heating. All these configura-

tions can be applied with convenient connections to outdoor

thermostat applications.

The following sections will be detailed:

• Single Stage Cooling (GMC Thermostat part # CHT18-

60 or equivalent)

• Heat Pump (GMC Thermostat part #HPT18-60 or equiva-

lent)

• Two Stage Cooling with Conventional Two Stage Ther-

mostat (GMC Thermostat part #CHT90-120 or equiva-

lent)

• Two Stage Cooling with Conventional Two Stage Ther-

mostat (Encoded with Add-on Diodes)

• Two Stage Encoded Thermostat from Goodman Manu-

facturing Part #CHET18-60

Each diagram details the connections between room thermo-

stat and MB air handlers, and the connections between the

MB air handlers and the Condensing Unit (or Heat Pump) with

optional connections to Outdoor Thermostats. For each con-

figuration,

refer to the explanation of the proper jumper(s) to remove for

the corresponding blower speed that will result in the pro-

grammed ECM

motor on MBE units.

Important: When matching the MBE air handlers to a single

stage cooling unit or heat pump, remember to connect the “Y/

Y2” thermostat connection on the Variable speed board (VSTB)

to the thermostat. Connecting “Y1” will result in first stage

cooling blower speed.

Note: The two stage configurations are illustrated to detail con-

nections to the two capacity condensing units and heat pumps.

An equivalent thermostat can be used in place of the Goodman

thermostat part number. The GMC thermostats listed are

mercury type.

When utilizing the encoded version of a conventional two stage

cooling and heating electronic thermostat (add-on diodes), a

hard wire “C” (common of 24V secondary voltage) must be

used. This encoded version will not work with a “power robbing”

thermostat (i.e. no common connection). One TSTWK01 kit

is required for the encoded applications on MBE units.

NOTE: When using a conventional two stage thermostat for cooling

or heat pump applications with a two stage compressor, dip switch

#4 must be set to the “OFF” position on MBE units.

MBE MOTOR

This section references the operation characteristics of the

MBE model motor only. The ECM control board is factory set

with the dipswitch #4 in the “ON” position and all other

dipswitches are factory set in the “OFF” position. For most

applications, the settings are to be changed according to

the electric heat size and the outdoor unit selection.

The MBE product uses a General Electric ECM

motor. This

motor provides many features not available on the traditional

PSC motor. These features include:

• Improved Efficiency

• Constant CFM

• Soft Start and Stop

• Improved Humidity Control

MOTOR SPEED ADJUSTMENT

Each ECM™ blower motor has been preprogrammed for op-

eration at 4 distinct airflow levels when operating in Cooling/

Heat Pump mode or Electric Heat mode. These 4 distinct

levels may also be adjusted slightly lower or higher if desired.

The adjustment between levels and the trim adjustments are

made by changing the dipswitch(s) either to an "OFF" or "ON"

position.

DIPSWITCH FUNCTIONS

The MBE air handler motor has an electronic control that con-

tains an eight (8) position dip switch. The function of these

dipswitches are shown in Table 1.

Dipswitch Number Function

N/A

Indoor Thermostat

Cooling & Heat Pump CFM

CFM Trim Adjust

Electric Heat

Table 1

CFM DELIVERY

Tables 2 and 3 show the CFM output for dipswitch combina-

tions 1-2, and 5-6.