13
6. ACCESSORIES
Relay Boxes
Only the M1GH requires a relay box. All other M1G and M1M
furnaces are AC ready. The M1GH series furnaces are
certified to be used with either a 4 wire relay box (p/n 902898A)
or a 2 wire relay box (p/n 903092A). Follow the instructions
included with the relay box for proper installation.
Cooling Blowers
If you are installing an AC system which exceeds the maxi-
mum AC capacity of your system, a larger blower will have to
be installed. A blower assembly may also need to be installed
for high static pressure applications or crossover systems.
Refer to “Blower Data” for further information.
A/C Capacity
Blower Wheel
Motor-Hp
Ton
903412
10 x 8
1/3
2, 2½ & 3
903413
11 x 8
1/2
2, 2½, 3 & 4
903414
10 x 8
3/4
2, 2½, 3, 4 & 5
Part No.
Blower / Motor Assembly
Table 8. Field Installation Blower Assemblies
Fan Timer Kit
The M1G furnace uses a temperature activated switch type
fan control (The M1M uses a time delayed control, so this
information does not apply). A fan timer kit may need to be
installed with this type of switch if the following conditions
exist:
1.
Very cold outside air temperatures being drawn in through
the VentilAire system.
2.
Night time thermostat set back to a very low temperature.
3.
System is left off for extended periods of time.
The fan may be cycling during a normal call for heat. For gas
models, make sure the gas valve is reaching high fire. If there
are no problems with the firing rate, install a Nordyne fan timer
kit, part number 903490. See instructions with kit for installa-
tion. Since many factors outside our control may contribute
to blower short cycling, Nordyne does not consider this to be
a warranty issue.
Optional Add-On Air Conditioning – Packaged Units
Necessary when the Furnace is Used with Some Central Air
Conditioners – If an air conditioner is installed that does not
use the furnace blower for air distribution and that operates
independently of the furnace, the thermostat system must
have an interlock to prevent the furnace and air conditioner
from operating at the same time. This interlock system usually
contains either a “Heat-Cool” switch which must be turned to
the “Heat” or “Cool” position to activate either heating or
cooling operation, or a positive “OFF” switch on the cooling
thermostat.
Figure 12. Coil Cavity
Damper
Figure 13. Damper without
Coil Cavity
The furnace must also be equipped with an automatic damper
(See Figure 37 or 38, NORDYNE p/n 901996 for furnaces
without coil cavity, or p/n 901083 with coil cavity) to prevent
cold air from being discharged up around the heat exchanger.
Cold air may cause condensation inside the heat exchanger,
which can lead to rust and early failure.
Optional Add-On Air Conditioning – Split Systems
There is a NORDYNE split-system or package air conditioner
designed for your total comfort needs. Whether split system
or single package, an energy-saving NORDYNE unit is avail-
able that has been designed specifically for manufactured
housing applications and can best handle your home comfort
needs.
Listed and ARI Certified, all models are protected by the
NORDYNE Air Conditioner Limited Warranty.
Split system units with vertical discharge for quiet operation
connect to the NORDYNE cooling coil furnace (optional coil
cavity required with “A” model furnaces).
All Weather Cap - Roof Jack Accessories
1.
In case of high wind or icy conditions, a 903656 all
weather cap may be needed. See Pilot Outage section.
2.
In regions where snow can accumulate and cover any
portion of the roof jack, up to two optional external
extensions can be added — part #901937- each 16” long.
