2
INSTALLATION
Remove both access panels.
For GMP & GMPV series units, cut the white jumper wire
between pins 1 & 4 of the 9 pin connector.
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).
Remove the existing HSI module. Care should be exer-
cised as not to damage the nylon standoffs.
Install the 50T35-743 module.
Reconnect the edgecard connector making sure of good
contact.
Pushthe9pin connectorintotheHSI module.Itcango in
only one way. DO NOT force.
Reconnect the supplied thermostat wires.
Removetheredwirefromthe24voltsideofthesecondary
side of the transformer and discard.
Remove the blue ground wire from the transformer. DO
NOT discard.
Remove the blue wire from the transformer and discard.
Placethe red wire from the9 pinconnector onto "24volt"
of the secondary side of the transformer.
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.
Place the blue ground wire, which was previously re-
moved, on to the "Common" terminal of the trans-
former.
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.
SELECTING THE BLOWER OFF DELAY
Inthe heatingmode, 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.
Thecontrolisfactorysettogivea(150)secondbloweroff
delay. See drawing below for the jumper position for all
available settings:
Notes:
• If the jumper is removed, the control will default to a
(150) second blower off delay in the heating mode.
• The blower on time in the heating mode is (30)
seconds and is non-adjustable.
• Theblowerontimeinthecoolingmodeis(7)seconds
and is non-adjustable.
• The blower off delay in the cooling mode is (60)
seconds and is non-adjustable.
• Caution is to be exercised not to bend the metal pins
whenchangingthetimedelayfromthefactorysetting.
STATUS
90
120
150
P3
JUMPER SET
STATUS
90
120
150
P3
JUMPER SET
STATUS
90
120
150
P3
JUMPER SET
FOR 90 SEC. FOR 120 SEC. FOR 150 SEC.
BLOWER
TIME OFF
JUMPER 90
120
150
STATUS
P3
TWIN
W
G
R
Black
White
24 v. Red
Com. Blue
GND. Blue
TRANSFORMER
115v. Supply
The Emerson logo is a
trademark and a service mark
of Emerson Electric Co.
