Nordyne MGHA Series User Manual

Installation Instructions
Gas Furnaces - Blower & Relay
WARNING:
Figure 1. MGHA and MMHA Series Gas Furnace
Shut off electrical supply to the furnace at
the household breaker box to prevent electri-
cal shock which could cause personal injury.
DANGER:
For MGHA and MMHA Series, Models -05 only, and M1 Series Furnaces
The p/n 903092A 2-wire and p/n 902898A A/C Heat Pump (4 to 7 wire) Relay Boxes install with cur-
rent M1, MGHA and MMHA models of NORDYNE gas furnaces with the new standardized blower
assembly. The 2-wire Relay Box has control switches which are operable through an opening in the
furnace door on MGHA and MMHA furnaces.
IMPORTANT INFORMATION
Read all instructions carefully before starting the installation. Specifi cations or designs are subject
to change or to discontinuance without notice and without incurring obligations.
These instructions are primarily intended to assist qualifi ed individuals experienced in the proper installation of heating and/or air
conditioning appliances. Some local codes require licensed installation/service personnel for this type of equipment. Read all instruc-
tions carefully before starting the installation.
Improper installation may damage equipment,
can create a hazard, and will void the war-
ranty.
!
!
Blower
Screws
Field Installed
Thermostat Wires
Furnace
System Switch
Furnace
Thermostat Wires
Furnace
Control Box
Blower
Plug
Decorative
Nameplate
Insert
Additional
Nameplate Insert
(on older models)
Door Control
Frame
Fig 2. M1* Furnace
Blower
Screw
Relay
Box
Field Installed
Thermostat
Wires
Blower
Plug
Thermostat
Leads
Fan On/Auto
Switch
(on Heating
only Models)

Nordyne MGHA Series Specifications

General

Heating Stages	Single Stage
Ignition Type	Direct Spark Ignition
AFUE Rating	80%
Thermostat Compatibility	Standard
Fuel Type	Gas
Heating Capacity	40, 000 to 120, 000 BTU/h
Warranty	10-Year limited warranty on heat exchanger

Summary

Important Information and Safety Warnings

General Warning

Improper installation may damage equipment, create a hazard, and void the warranty.

Electrical Danger

Shut off electrical supply at the breaker box to prevent electrical shock and personal injury.

Installation Sequence

Blower Speed Selection

Guide for selecting appropriate blower speeds for heating and cooling based on furnace input and cooling capacity.

System Operation

AC/Heat Pump Relay Box Operation

Instructions for setting thermostat and fan switches for heating, cooling, and circulation modes.

2-Wire Relay Box Operation

Instructions for setting switches on the relay box for heating, cooling, and circulation modes.