Robertshaw Uni-Kit 780-001 Installation and user guide

INSTALLATION DATA
780-001 / 780-002 / 780-003
Universal ignition ModUle
replaceMent Uni-Kit®
Robertshaw® Universal Ignition Control Uni-Kit®is available in both
nonlockout (780-001) and lockout (780-002). The 780-003 is lockout
with a prepurge function.
The Universal Ignition Control Uni-Kits feature a flame sense circuit
that automatically detects the presence of a remote sense probe (2
rod system) or it switches to local sense (1 rod system) utilizing the
pilot assembly as a sensing source. If both systems are provided,
failure of one causes automatic reversion to the other.

The automatic recycle features assure that, in the event of flame
failure, main gas is disabled and the spark repetition sequence is
restarted until pilot gas is ignited. Only after pilot ignition has been
reestablished can main gas be returned to the burner.

These kits have a lockout feature to shut off all gas to the furnace,
should pilot ignition fail to occur after a predetermined time period.
The 780-002 provides 3 tries for ignition. Each ignition period is 60
seconds followed by a 5 minute time delay between ignition attempts.
After 3 tries if no pilot flame is sensed, unit goes into lockout and must
be reset at the thermostat.




Input voltage 24V AC to 50/60 Hz
Transformer 24V AC / 20 VA
Safety lockout timing
(780-002 only)
60 seconds*
Prepurge (780-003 only) 45 seconds*
Spark rate 3 to 4 sparks per second
Relay contact ratings
Pilot valve 1 amp at .5 PF
Main valve 1 amp at .5 PF
Combined load 1.5 at .4 PF
Flame sense current .7 µA DC @ 25°C / 24 VAC
Maximum total current load 1.5 amp
Flame failure reignition time .8 seconds maximum
Thermostat anticipator setting .7 amp
Ambient temperature rating - 40°F to 175°F
(- 40°C to 80°C)
Relative humidity 95% noncondensing at 104°
*The SP745 lockout ignition control used in the 780-002 and
780-003 Uni-Kit provides 3 tries for ignition. Each ignition period
is 60 seconds followed by a 5 minute time delay between
ignition attempts. After 3 tries if no pilot flame is sensed, the
unit goes into lockout and must be reset at the thermostat.

2



1. Turn OFF all electrical power to the appliance being serviced.
2. Remove the old ignition control unit, but leave the wires
connected at this time.
3. Install the new Universal Ignition Control Module in the same
location as the old one.
4. Locate the 'grey or white plug' assembled to the SENSOR
terminal. Remove it and discard. It is no longer required.
5. Remove one wire at a time from the old l.C.U. Reconnect it to
the same terminal on the new Universal l.C.U. Example: PV to
PV.
6. The wiring and installation of the new ignition module is now
compete.
7. Restore electrical power to the appliance being serviced.
Proceed as directed in SYSTEM CHECKOUT PROCEDURES
section.
780-715*
Replaces:
SP715, SP715A, USI715U
780-745*
Replaces:
SP735, SP735A, SP745†
*Uni-Line part number for the individual model
†Intermittent (spark pilot) model only

The Robertshaw 780-001 (nonlockout), 780-002 (lockout) and
780-003 (lockout with prepurge) Universal Replacement Module
Uni-Kit®is designed to replace the Johnson Controls Spark Ignition
System Modules listed on pages 5 and 6. The 780-002 kit must be
used whenever a Johnson Controls Y79 Series lockout module is
present on the system being serviced.
The 780-001 and 780-002 Uni-Kit replaces only the existing
control module, while utilizing the existing Johnson gas valve,
pilot sensor and ignitor. The Uni-Kit includes a special mounting
bracket for mounting the new module onto the existing gas
valve. A special wiring adaptor, (included with the Uni-Kit) is used
whenever the existing system includes a Johnson Controls M15/
Y15 Series Vent Damper.


1. Locate the Johnson Controls part number on the existing
module.
2. Find this number in the cross-reference list (pages 5 and 6) to
determine which wiring diagram to use.
Refer to Wiring
Diagram Number
Existing Module (Control Part)
Part Number
3. Over the years Johnson Controls has gone through many
different model variations of ignition control units. Along
with the many different models, Johnson Controls has
also had dozens of different wiring combinations for these
controls.
We have provided for you what we feel are the most accurate
wiring schematic(s) that we can. If you encounter problems with
your wiring, Robertshaw I.C.U. terminals and their functions are
listed below:
TH = 24 volt signal from wall thermostat
PV = Pilot valve - pilot gas only
MV = Main valve - main burner gas
SENSOR = Flame sensor (2 rod system)
ACCESSORY TERM E3 = Not used
MV/PV = Common return for MV and PV (grounded)
TR = Transformer common (grounded)
GND. = Ground
IGNITOR = Spark electrode lead wire

3


CAUTION: 



NOTE: The following instructions are based on the premise that
the appliance being serviced is in correct operating order
except for the failed control module. If other problems are
present, they must be corrected or the new module may
not perform correctly.
1. Turn off all electrical power to the appliance being serviced.
2. Using the wiring tags provided, label each wire with the old
terminal designation as you disconnect it. It is not necessary
to label the high voltage cable as it is readily identifiable.
3. If a vent damper wiring harness (not just the "dummy plug")
is plugged into the six-pin molex connector, make sure that
you use the 1751-724 (G60 Vent Damper Adaptor), included
with the Uni-Kit.
4. Remove and discard the screws that held the ignition module
(control part) onto the mounting plate. Discard the old
ignition module. See Figure 1.
Figure 1


1. Locate the G60 adaptor bracket, 6" green grounding wire and
using the two #12 x 1/2" sheet metal screws provided, mount
the adaptor bracket and 6" ground wire to the gas valve
mounting plate as shown in Figure 2. The adaptor bracket fits
onto the mounting plate in more than one position. Use the
position that gives the easiest access to the mounting screw
locations. Actual orientation of the bracket is not important.
The screws will accept either a 1/4" flat screwdriver or a
5/16" nut driver. Make sure no wires are pinched between the
bracket and mounting plate.
2. Locate the 'grey or white plug' assembled to the SENSOR
terminal. Remove it and discard. It is no longer required.
3. Remove the protective backing from one side of the double-
sided tape. Place the side of the tape with the exposed
adhesive on the bottom of the new Robertshaw ignition
module.
4. Referring back to the appropriate wiring instructions, place
the wires on the correct terminals.
5. Remove the remaining protective backing from the double-
sided tape on the ignition module. Center the module over
the previously installed bracket and press down. See Figure 2.
3" x 3" Double-sided Tape
#12 x 1/2 Hex Screw G60 Adaptor Bracket
6" Green
Grounding Wire
Existing Gas Valve
(Wires Not Shown for
Clarification)
Figure 2
6. Connect the green ground wire, that was attached in Step
1, to any one of the following terminals that are not already
being used; GND, MV/PV or TR.

4
7. Locate the high voltage cable adaptor included in the kit.
Attach it to the IGNITOR terminal on the new ignition module.
See Figure 3.
High Voltage
Cable Adaptor
IGNITOR
Terminal
Figure 3
8. Attach the existing high voltage cable (from the pilot ignitor)
to the high voltage cable adaptor or IGNITOR terminal.
9. If a vent damper is present in the system, proceed as follows,
if not proceed to Step 10.
A. Locate the orange lead wire on the 1751-724 adaptor,
See Figure 4. Wire nut it to the power lead that came off
terminal #5 or #6 on the old unit.
B. Wire nut the red wire on the 1751-724 adaptor to the
thermostat wire. This is the wire that was connected to
terminal #2 on the old unit.
C. Connect the gray wire on the 1751-724 to the TH
terminal on the new module.
Figure 4
10. The wiring and installation of the new ignition module is now
complete.
11. Restore electrical power to the appliance being serviced.
Proceed as directed in SYSTEM CHECKOUT PROCEDURES
section.

5


 








CSA35A-617R 780-001 3 5
CSA35A-618R 780-001 3 5
CSA42A-600R 780-001 3 4
CSA42A-601R 780-001 3 4
CSA42A-602R 780-001 3 4
CSA42A-603R 780-001 3 4
CSA42A-604R 780-001 3 4
CSA43A-600R 780-001 3 4
CSA44A-600R 780-001 3 4
CSA45A-601R 780-001 3 4
CSA45A-602R 780-001 3 4
CSA46A-600R 780-001 3 4
CSA48A-600R 780-001 3 4
CSA49A-600R 780-002 3
CSA49A-601R 780-002 3
CSA49A-605R 780-002 3
CSA51A-601R 780-002 3
CSA52A-600R 780-002 3
G600AX-1 780-001 3
G600AX-2 780-002 3
G600AX-3 780-002 3
G600AY-1 780-001 5
G600KX-1 780-002 3
G600LX-1 780-002 3
G600LX-2 780-002 3
G600LY-1 780-002 5
G600MX-1 780-002 3
G600NX-1 780-002 3
G600RX-1 780-002 3
G60AAA-1 712-017 3
G60AAG-1 780-001 3 5
G60AAG-2 780-002 3 5
G60AAG-3 780-001 3 5
G60AAG-4 780-001 3 5
G60AAG-5 780-001 3 5
G60AAG-6 780-001 3 5
G60AAG-7 780-002 3
G60CAA-1 712-017 3
G60CAA-3 712-017 3
G60CAG-1 780-002 3 5
G60CAG-2 780-002 3 5
G60CAG-3 780-002 3 5
G60CAG-4 780-002 3 5
G60CAG-5 780-001 3 5
G60CAG-6 780-002 3 5
G60CAG-7 780-002 3 5
G60CAG-8 780-002 3 5
G60CAG-9 780-002 3 5
G60CBA-1 712-017 3
G60CBA-2 712-017 3
G60CBA-3 712-017 3
G60CBG-1 780-001 3 5
G60CBG-10 780-001 3 5
G60CBG-11 780-001 3 5
G60CBG-12 780-001 3 5
G60CBG-14 780-001 3 5
G60CBG-16 780-001 3 5
G60CBG-17 780-001 3 5
G60CBG-2 780-002 3 5
G60CBG-3 780-002 3 5
G60CBG-4 780-002 3 5
G60CBG-5 780-002 3 5
G60CBG-6 780-002 3 5
G60CBG-7 780-002 3 5


 








G60CBG-8 780-002 3 5
G60CBG-9 780-002 3 5
G60CCA-1 712-017 3
G60CCG-1 780-001 3 5
G60CPG-1 780-001 3 5
G60DBG-1 780-001 3 5
G60DBG-2 780-001 3 5
G60DCG-1 780-001 3 5
G60DCG-2 780-001 3 5
G60DCG-3 780-001 3 5
G60DCG-4 780-001 3 5
G60DGB-1 780-001 3
G60PAG-1 780-001 3
G60PAG-2 780-001 3 4
G60PAG-3 780-001 3 4
G60PAG-4 780-001 3 4
G60PAG-5 780-001 3 4
G60PAG-6 780-001 3 4
G60PAJ-1 780-001 3 4
G60PAK-1 780-001 3 4
G60PAK-2 780-001 3 4
G60PFH-1 780-002 3
G60PFH-2 780-002 3
G60PFL-1 780-002 3
G60PFQ-1 780-001 3
G60PML-1 780-002 3
G60PVL-1 780-002 3
G60QAG-1 780-002 3 4
G60QAG-2 780-001 3 4
G60QAG-3 780-002 3 4
G60QAG-4 780-001 3 4
G60QAK-1 780-002 3 4
G60QBG-1 780-001 3 4
G60QBG-2 780-001 3 4
G60QBG-3 780-001 3 4
G60QBG-4 780-001 3 4
G60QBG-5 780-001 3 4
G60QBG-6 780-001 3 4
G60QBG-7 780-001 3 4
G60QBG-8 780-001 3 4
G60QBG-9 780-001 3 4
G60QBH-1 780-001 3 4
G60QBK-1 780-001 3 4
G60QBK-2 780-002 3 4
G60QBK-3 780-002 3 4
G60QBL-1 780-001 3 4
G60QBL-2 780-001 3 4
G60QCG-1 780-002 3 4
G60QCJ-1 780-001 3 4
G60QCL-1 780-001 3 4
G60QDG-1 780-001 3 4
G60QFL-1 780-002 3 4
G60QGH-1 780-002 3 4
G60QHL-1 780-002 3
G60QHL-2 780-002 3
G60QJL-1 780-002 3
G60QLG-1 780-001 3 4
G60QLK-1 780-002 3 4
G60QPL-1 780-001 3 4
G60QRH-1 780-002 3
G60QRH-2 780-002 3
G60QRH-3 780-002 3
G60QRL-1 780-002 3
G60QRL-2 780-001 3


 








G60QRL-3 780-001 3
G60QSL-1 780-002 3
G60QTH-1 780-002 3
G60QTL-1 780-002 3
G60QUL-1 780-002 3
G60RAG-1 780-001 3 4
G60RBG-1 780-001 3 4
G60RBG-2 780-001 3 4
G60RBG-3 780-001 3 4
G60RBK-1 780-001 3 4
G60RBK-2 780-001 3 4
G60RCG-1 780-001 3 4
G60RCG-2 780-001 3 4
G60RCJ-1 780-001 3 4
G60RDG-1 780-001 3 4
G60RDK-1 780-001 3 4
G60RGL-1 780-002 3
G60RHL-1 780-002 3
G60RHP-1 780-001 3
G60RPL-1 780-001 3 4
G60RSL-1 780-002 3
G60ZAG-1 780-002 3 4
G60ZAG-2 780-002 3 4
G65BBG-1 780-001 3 4
G65BBG-2 780-001 3 4
G65BBG-3 780-001 3 4
G65BBG-4 780-001 3 4
G65BBG-5 780-001 3 4
G65BBG-6 780-001 3 4
G65BBG-7 780-001 3 4
G65BBG-8 780-001 3 4
G65BBM-1 780-001 3
G65BBM-2 780-001 3
G65BBM-3 780-001 3
G65BBM-4 780-001 3
G65BCG-1 780-001 3 4
G65BCM-1 780-001 3
G65BFG-1 780-001 3 4
G65BKG-1 780-001 3 4
G65BKG-2 7801-001 3 4
G65BKG-3 780-001 3 4
G65BKM-1 780-001 3
G65BKM-2 780-001 3
G65BKM-3 780-001 3
G65BLG-1 780-002 3 4
G65BLG-2 780-001 3 4
G65DBM-1 780-002 3 4
G65DBM-2 780-002 3
G65DBM-3 780-002 3
G65DCM-1 780-002 3
G65DFM-1 780-002 3
G65DKM-1 780-002 3
G65DLM-1 780-002 3
G65QBM-1 780-002 6
G65QBM-3 780-002 6
G66AG-1 780-001 3 4
G66AG-2 780-001 3 4
G66BG-1 780-001 3 4
G66MG-1 780-002 3
G66MG-2 780-002 3
G66NG-1 780-002 3
G670AW-1 780-002 6
G670AW-2 780-002 6
G67AG-10 780-002 6 2

6
 JOHNSON CONTROLS ROBERTSHAW
1 (PV) PV•
2 (THS) TH
3 (MV) MV•
4 SENSOR
5 NOT USED
GRD. *
*On the Robertshaw I.C.U. the following terminals are grounded; MV/
PV, TR and GND.
•Connect the grounded leads of the PV and MV from the Johnson
Controls module to the MV/PV terminal on the Robertshaw I.C.U.


 








G67AG-11 780-002 6
G67AG-3 780-002 6
G67AG-4 780-002 6
G67AG-7 780-002 6
G67AG-8 780-002 6
G67AG-9 780-002 6 2
G67BG-2 780-002 7 8
G67BG-3 780-002 7 8
G67BG-4 780-002 7 8
G67BG-5 780-002 7 8
G67KG-1 780-002 3
G67LG-1 780-002 3
G67MG-1 780-002 3
G67MG-2 780-002 3
G67MG-3 780-002 3
G67MG-4 780-002 3
G67NG-2 780-002 3
G67NG-4 780-002 3
G770KGA-1 780-002 1
G770KHA-1 780-002 1
G770KHA-2 780-001 1
G770LGA-1 780-002 1
G770LGA-2 780-002 1


 








G770LGC-1 780-002 1
G770LGC-2 780-002 1
G770LGC-3 780-002 1
G770LGC-4 780-002 1
G770LHA-1 780-002 1
G770LHA-2 780-002 1
G770LHC-1 780-003 1
G770MGA-1 780-002 1
G770MGA-2 780-002 1
G770MGA-3 780-002 1
G770MGC-1 780-002 1
G770MGC-2 780-002 1
G770MGC-3 780-002 1
G770MGC-4 780-002 1
G770MGC-5 780-002 1
G770MGC-6 780-002 1
G770MHA-1 780-002 1
G770MHA-2 780-002 1
G770MHC-1 780-003 1
G770NGA-1 780-002 1
G770NGC-4 780-002 1
G770NGC-5 780-002 1
G770NGC-6 780-002 1


 








G770NGC-7 780-002 1
G770NHA-1 780-002 1
G770NHC-1 780-003 1
G770RGA-1 780-002 1
G770RHA-1 780-002 1
G770RHA-2 780-002 1
G775RGA-1 780-002 1
G775RHA-1 780-002 1
G775RHA-2 780-002 1
G779LHA 780-002 1
Y79ABC-1 780-002 *
Y79ABC-2 780-002 *
Y79ABC-3 780-002 *
Y79ABC-4 780-002 *
Y79ABC-5 780-002 *
Y79ABC-6 780-002 *
Y79ABC-7 780-002 *
Y79ABD-1 780-002 *
Y79ABD-2 780-002 *
Y79BBA-1 780-002 *
Y79BBA-2 780-002 *
CAUTION:
CAUTION:
*To determine the correct wiring diagram, find the Johnson Control I.C.U. model number in this chart and follow the wiring diagram indicated.

7

See Step 6 on page 3
JOHNSON CONTROLS ROBERTSHAW
1PV•
2 TH
3MV•
4 SENSOR
5 NOT USED
6†
GRD. *
*On the Robertshaw I.C.U. the following terminals are grounded; MV/
PV, TR and GND.
Connect the THS lead from the Johnson Controls Y79 module to the
TH terminal on the Robertshaw I.C.U.
†This is a hot wire from the 24V transformer secondary and is not
used in the Robertshaw installation. Cut off the connector, utilizing
the supplied wire nut; connect any wires on terminal 6 together, or
insulate the single wire and secure in the appliance.
•Connect the grounded leads of the PV and MV from the Johnson
Controls module to the MV/PV terminal on the Robertshaw I.C.U.
Cut the thermostat lead at the Y79A module and connect it to
the TH terminal on the Robertshaw I.C.U. On this application, the
Robertshaw I.C.U. (780-002) has the lockout feature built-in. Therefore
the Johnson Controls Y79A lockout module can be removed and
discarded.
 JOHNSON CONTROLS ROBERTSHAW
1PV
2 TH
3 MV
4 SENSOR
5 NOT USED
6 †
GRD. *
*On the Robertshaw I.C.U. the following terminals are grounded; MV/
PV, TR and GND.
†This is a hot wire from the 24V transformer secondary and is not
used in the Robertshaw installation. Cut off the connector, utilizing
the supplied wire nut; connect any wires on terminal 6 together, or
insulate the single wire and secure in the appliance.

8
 JOHNSON CONTROLS ROBERTSHAW
1PV
2 TH
3 MV
4 SENSOR
5 NOT USED
6†
GRD. *
*On the Robertshaw I.C.U. the following terminals are grounded; MV/
PV, TR and GND.
†This is a hot wire from the 24V transformer secondary and is not
used in the Robertshaw installation. Cut off the connector, utilizing
the supplied wire nut; connect any wires on terminal 6 together, or
insulate the single wire and secure in the appliance.
Cut the MV wire at the Y79B module and connect it to the MV
terminal on the Robertshaw I.C.U. Cut the PV wire at the Y79B module
and connect it to the PV terminal on the Robertshaw I.C.U. Connect
the grounded leads from the MV and PV to the MV/PV terminal on
the Robertshaw I.C.U. On this application, the Robertshaw I.C.U. (780-
002) has the lockout feature built-in. Therefore the Johnson Controls
Y79B lockout module can be removed and discarded.
 JOHNSON CONTROLS ROBERTSHAW
1PV
2
3 MV
4 SENSOR
5 NOT USED
6†
GRD. *
*On the Robertshaw I.C.U. the following terminals are grounded; MV/
PV, TR and GND.
†This is a hot wire from the 24V transformer secondary and is not
used in the Robertshaw installation. Cut off the connector, utilizing
the supplied wire nut; connect any wires on terminal 6 together, or
insulate the single wire and secure in the appliance.
Cut the thermostat lead at the Y79A module and connect it to
the TH terminal on the Robertshaw I.C.U. On this application, the
Robertshaw I.C.U. (780-002) has the lockout feature built-in. Therefore
the Johnson Controls Y79A lockout module can be removed and
discarded.

9

See Step 6 on page 3
JOHNSON CONTROLS ROBERTSHAW
1PV•
2 TH
3MV•
4 SENSOR
5 NOT USED
6†
GRD. *
*On the Robertshaw I.C.U. the following terminals are grounded; MV/
PV, TR and GND.
†This is a hot wire from the 24V transformer secondary and is not
used in the Robertshaw installation. Cut off the connector, utilizing
the supplied wire nut; connect any wires on terminal 6 together, or
insulate the single wire and secure in the appliance.
•Connect the grounded leads of the PV and MV from the Johnson
Controls module to the MV/PV terminal on the Robertshaw I.C.U.

See Step 6 on page 3
 
1PV†
2 TH
3MV†
4 SENSOR
5 NOT USED
6 NOT USED
GRD. *
*On the Robertshaw I.C.U. the following terminals are grounded; MV/
PV, TR and GND.
†Connect the grounded side of the PV and MV from the Johnson
Controls module to the MV/PV terminal on the Robertshaw I.C.U.

See Step 6 on page 3
 
1
2 TH
3
4 SENSOR
5 NOT USED
6 NOT USED
GRD. *
*On the Robertshaw I.C.U. the following terminals are grounded; MV/
PV, TR and GND.
Connect the grounded side of the PV and MV from the Johnson
Controls module to the MV/PV terminal on the Robertshaw I.C.U.
Connect the MV wire from the Y79B module to the MV terminal on
the Robertshaw I.C.U. Connect the PV wire from the Y79B module
to the PV terminal on the Robertshaw I.C.U. On this application,
the Robertshaw I.C.U. (780-002) has the lockout feature built-in.
Therefore the Johnson Controls Y79B lockout module can be removed
and discarded.

10

The Robertshaw 780-001 (nonlockout), 780-002 (lockout) and 780-
003 (lockout with prepurge) Universal Replacement Module Uni-
Kits®are designed to replace the Honeywell Spark Ignition System
Modules shown on page 11. The 780-002 or 780-003 kit must be
used whenever a Honeywell lockout module is present on the
system being serviced.
The Uni-Kits replace  the existing control module, while
utilizing the existing Honeywell gas valve, pilot sensor and ignitor.
A special wiring adaptor, (included with the Uni-Kit) is used
whenever the existing system includes a Vent Damper.


1. Locate the Honeywell part number on the existing module.
2. Find this number in the cross-reference list (page 11) to
determine which wiring diagram to use.
Refer to Wiring
Diagram Number
Existing Module (Control Part)
Part Number
3. Over the years Honeywell has gone through many different
model variations of ignition control units.
We have provided for you what we feel are the most accurate
wiring schematic(s) that we can. If you encounter problems with
your wiring, Robertshaw I.C.U. terminals and their functions are
listed below:
TH = 24 volt signal from wall thermostat
PV = Pilot valve - pilot gas only
MV = Main valve - main pilot
SENSOR = Flame sensor (2 rod system)
ACCESSORY TERM E3 = Not used
MV/PV = Common return for MV and PV (grounded)
TR = Transformer common (grounded)
GND. = Ground
IGNITOR = Spark electrode lead wire


CAUTION: 



NOTE: The following instructions are based on the premise that
the appliance being serviced is in correct operating order
except for the failed control module. If other problems are
present, they must be corrected or the new module may
not perform correctly.
1. Turn off all electrical power to the heating appliance being
serviced.
2. Remove the Red ignitor wire or cable from the Honeywell
ignition module. Place the wire out of the way for now.
3. Disconnect the wires from the Honeywell module one at a
time and reconnect it to the appropriate terminal on the 780
kit module. Follow the wiring instructions shown in Figure 5.
Figure 5
4. Remove Honeywell module and install new 780 kit module in
its place using old mounting screws or new mounting screws
or double-sided tape provided.
5. Locate the ignitor terminal adaptor included in the kit. Install
the adaptor onto IGNITOR terminal on new module, See
Figure 6. Connect ignitor lead to the adaptor.
High Voltage
Cable Adaptor
IGNITOR
Terminal
Figure 6
6. If a vent damper is present in the system, proceed as follows,
if not proceed to step #7.
A. Locate the orange lead wire on the 1751-724 adaptor,
See Figure 5. Wire nut it to the power lead that came off
terminal 25V+ on the old unit.
B. Wire nut the red wire on the 1751-724 adaptor to the
thermostat wire. This is the wire that was connected to
terminal #2 on the old unit.
C. Connect the gray wire on the 1751-724 to the TH
terminal on the new module.
D. Connect the white wire on the 1751-724 adaptor to the
MV/PV terminal on the new 780 replacement module.