Goodman GMV series - Page 31

PRODUCT DESIGN
31
Corrections must be in accordance with the latest edition of
the National Fuel Gas Code NFPA 54/ANSI Z223.1 and/or
CSA B149 Installation Codes.
If resizing is required on any portion of the venting system,
use the appropriate table in Appendix G in the latest edition
of the National Fuel Gas Code ANSI Z223.1 and/or CSA B149
Installation Codes.
Thermostat Requirements
A single-stage furnace requires a single-stage thermostat
while the two-stage furnace requires a two-stage thermostat
for proper operation (see note below). The single-stage ther-
mostat provides "W1" for only one stage of heat while the
two-stage thermostat provides "W1" and a "W2" terminals
for control of low stage and high stage heat. Refer to Electri-
cal Connections - 24 Volt Thermostat Wiring section in this
manual or the installation instructions for correct installation
procedure for these thermostats.
NOTE: A single-stage thermostat with only one heating
stage can be used to control a two-stage furnace. The ap-
plication of a single-stage thermostat does not offer "true"
thermostat driven two-stage operation, but provides a timed
transition from low to high fire. The furnace will run on low
stage for a fixed period of time before stepping up to high
stage to satisfy the thermostat's call for heat. The delay
period prior to stepping up can be set at either 5 or 10 min-
utes through the DIP switch adjacent to the Heat Off delay
DIP switches on the integrated control module. To use a
single-stage thermostat, turn off power to the furnace, move
the thermostat selection jumper on the integrated contro
module from the "two-stage" position to the "single-stage"
position, turn power back on. Refer to the following figures.
3
2
1
T
W
O
S
I
N
G
L
E
TSTAT
OFF
3
2
1
T-Stat selection jumper in
single-stage thermostat
position.
DIP switch position 3: ON
Delay Period: 10 minutes.
DIP switch position 3: OFF
Delay Period: 5 minutes.
T
W
O
S
I
N
G
L
E
TSTAT
ON
NOTE: The AMH, GCH, GDH, GMH and GME hybrid fur-
naces require a single stage thermostat. These furnaces
utilize a control board with single stage or two stage capa-
bility. The second stage feature is established by setting a
dip switch on the board, either one stage or two stage. All of
the second stage timing is then controlled by dipswitch 3 on
the circuit board.
O
N
O
F
F
2
O
N
O
F
F
3
SECOND
STAGE
ONLY
5
MINUTES
O
N
O
F
F
1
150
SECOND
DELAY
100
SECOND
DELAY
1-STAGE
2-STAGE
HEAT OFF
DELAY
MODE
AUTO
Dehumidistat Requirements
A dehumidistat can be used in conjunction with the two-
stage variable speed 80% or 90% furnace to lower the hu-
midity in the conditioned space. The dehumidistat will im-
prove dehumidification of the conditioned air by prompting
the furnace to reduce the speed of the circulator blower dur-
ing operation in the cooling mode. To be compatible with
these furnaces, a dehumidistat must operate on 24 VAC
and utilize a switch which opens on humidity rise. Refer
to Electrical Connections - 24 Volt Dehumidistat Wiring sec-
tion in this manual or the installation instructions for correct
installation procedure.
Thermostat and Dehumidistat Location
In an area having good air circulation, locate the thermostat
and dehumidistat (if applicable) about five feet high on a vi-
bration-free inside wall. Do not install the thermostat or
dehumidistat where it may be influenced by any of the fol-
lowing:
• Drafts, or dead spots behind doors, in corners, or un-
der cabinets.
• Hot or cold air from registers.
• Radiant heat from the sun.
• Light fixtures or other appliances.
• Radiant heat from a fireplace.
• Concealed hot or cold water pipes, or chimneys.
• Unconditioned areas behind the thermostat and
dehumidistat, such as an outside wall.
HOT
COLD
DRAFTS OR DEAD SPOTS
-BEHIND DOORS
-IN CORNERS
-UNDER CABINETS
Thermostat Influences