Wiring Diagrams - Lennox HP21 Installation Instructions Manual

7. Wiring connections for 3−pole, 25A contactor with end
switch:
a − Single−Phase units: Locate the 10" long 18−gauge
blue wire and connect one end to the normally
closed contacts (NC) of the end switch. Move the
wires from the existing 5−pole end switch to the
end switch terminals of the replacement 3−pole,
25A contactor (Com to Com, NO to NO and NC to
NC).
b − Three−Phase units: Move the wires from the
existing 5−pole end switch to the end switch
terminals on the new 3−pole, 25A contactor (Com
to Com and NC to NC).
NOTE − The provided 10" long 18−gauge blue wire
is not wired to the end switch on the three−phase
units.
8. Install the 3−pole, 25A contactor with the end switch on
the left side of the template as shown in figure 1.
9. Install the 3−pole 40A contactor on the right side of the
template as shown in figure 1.
10. Locate the 6" long 18−gauge yellow wire and install
each end to the common side terminals of both
replacement contactor 24 volt coils. See the wiring
diagrams in figures 2 through 7.
11. Contactor coil wiring:
a − Single−Phase units: Locate the 10" long 18−gauge
blue wire installed on the normally closed contacts
(NC) of the end switch. Route the other end of the
blue wire to the Hot coil terminal on the 3−pole, 40A
contactor (K226). See figures 2 through 6.
b − Three−Phase units: Move the wires that are on the
existing 5−pole coil onto the coil terminals of the
new 3−pole, 25A contactor. Locate the 10" long
18−gauge blue wire and connect one side of the
wire to the Hot coil terminal on the 3−pole, 40A
contactor and the other side to the Hot coil
terminal of the existing 3−pole, 25A contactor
(K69).
12. Confirm end switch and 24 volt coil wiring.
13. Transfer line voltage wiring from the 5−pole contactor
to the two 3−pole replacement contactors. See the
wiring diagrams in figures 2 through 7.
14. Confirm all electrical connections are tight.
15. Apply applicable wiring diagram on dry clean surface
beside existing factory wiring diagram.
16. Apply line and low voltage power to unit.
17. Perform operation sequence check. (Use operation
sequence in these instructions as reference.)
18. Confirm that all access panels are installed, all
controls are correctly set and operating mode has
been properly selected.
Compressor Compressor
Speed
Low
High

Wiring Diagrams

Point−to−point wiring diagrams which detail the changes
required during kit installation in single−phase units are
given in figures 2 and 3. See figure 4 for a schematic
diagram for a single−phase unit after the kit has been
installed.
Point−to−point wiring diagrams which detail the changes
required during kit installation in three−phase units are
given in figures 5 and 6. See figure 7 for a schematic
diagram for a three−phase unit after the kit has been
installed.
Page 2
Contactor Energized
Single Phase Three Phase
K1 and K226 K1
K1 and K69 K69 and K226