INSTALLATION
Remove both access panels.
SELECTING THE BLOWER OFF DELAY
For GMP & GMPV series units, cut the white jumper wire
between pins 1 & 4 of the 9 pin connector.
In the heating mode, the blower off delay can be selected
to obtain a 90, 120 or 150 seconds period. This can be
accomplishedbychangingthepositionofaplasticjumper
located on the ignition control. See the drawing below for
the location of this jumper.
For GMPN & GMN series units, DO NOT cut the white
jumper wire.
Removetheedgecardconnectorandotherwiresfromthe
existing module. Discard the thermostat wires re-
moved from the board (R, W & G).
TWIN
Remove the existing HSI module. Care should be exer-
cised as not to damage the nylon standoffs.
BLOWER
TIME OFF
JUMPER
STATUS
90
120
150
Install the 50T35-743 module.
Reconnect the edgecard connector making sure of good
contact.
W
G
R
Push the 9 pin connector into the HSI module. It can go in
only one way. DO NOT force.
Reconnect the supplied thermostat wires.
Removetheredwirefromthe24voltsideofthesecondary
side of the transformer and discard.
The control is factory set to give a (150) second blower off
delay. See drawing below for the jumper position for all
available settings:
Remove the blue ground wire from the transformer. DO
NOT discard.
Remove the blue wire from the transformer and discard.
Place the red wire from the 9 pin connector on to "24 volt"
of the secondary side of the transformer.
STATUS
90
STATUS
90
STATUS
90
Place the blue wire from the 9 pin connector on to
"Common" terminal of the secondary side of the
transformer. This wire has a piggy back terminal.
120
150
120
150
120
150
Place the blue ground wire, which was previously re-
moved, on to the "Common" terminal of the trans-
former.
JUMPER SET
FOR 90 SEC.
JUMPER SET
FOR 120 SEC.
JUMPER SET
FOR 150 SEC.
Notes:
•
•
•
•
•
If the jumper is removed, the control will default to a
(150) second blower off delay in the heating mode.
24 v. Red
Black
The blower on time in the heating mode is (30)
seconds and is non-adjustable.
115v. Supply
White
Com. Blue
Theblowerontimeinthecoolingmodeis(7)seconds
and is non-adjustable.
GND. Blue
The blower off delay in the cooling mode is (60)
seconds and is non-adjustable.
TRANSFORMER
Caution is to be exercised not to bend the metal pins
whenchangingthetimedelayfromthefactorysetting.
Replace the access panels.
Restore gas and electrical power to the furnace.
Verify the sequence of operation as noted in the Installa-
tion & Operating Instructions.
The Emerson logo is a
trademark and a service mark
of Emerson Electric Co.
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