Electric Heat - Lennox ELITE 12GCS Series Unit Information

3−Reversing Valve L1 (CHP only)
Reversing valve L1 has a 24 volt solenoid coil which re-
verses refrigerant flow during unit operation in all
12CHP units. The reversing valve is in the refrigerant circuit
vapor line.The reversing valve coil is energized during
cooling demand and during defrost.
4−Accumulator (CHP only)
All 12CHP units have an accumulator. The accumulator traps
and evaporates all liquid refrigerant and prevents liquid refriger-
ant from entering the compressor.
5−Defrost Thermostat Switch S6 (CHP only)
Defrost thermostat S6 is a S.P.ST. N.O. switch which closes on
temperature fall (initiating defrost). The switch is located on the
distributor assembly at the inlet of the outdoor coil.The switch
monitors the outdoor coil suction temperature to determine
when defrost is needed. When the outdoor coil suction temper-
ature falls to 32_F+ 4_F (0_C+ 2.2_C) the switch closes (initiat-
ing defrost after minimum run times of 30, 60, or 90 minutes).
The switch will open when the temperature rises to 55_F + 5_F
(12.7_C + 2.8_C).
6−Filter Drier (CHP only)
All 12CHP units have a filter drier in the liquid line. The drier
removes contaminants and moisture from the system.
7−High Pressure Switch (optional all models)
The high pressure switch is an auto−reset N.C. switch that
opens on pressure rise. This switch is an optional feature for all
models.The switch is wired in series with the compressor con-
tactor K1 and is located on the discharge line. When discharge
pressure rises to 450 psig (3102 kPa) the switch opens and
the compressor is de−energized. When discharge pressure
drops to 250 psig (1723 kPa) the pressure switch will close.
III−Electric Heat (optional 12CHP only)
A−Matchups and Ratings
Table 5 shows all approved ECH26 matchups and ratings.
B−Electric Heat Components
See figure 15 for electric heat parts arrangement.
1−Primary Limit S15
S15 is a N.C. auto−reset high temperature limit located on the
electric heat vest panel. Each heating element is wired in series
with a high temperature limit. When S15 opens, the corre-
sponding heating element is de−energized. All other heating
elements remain energized. S15 will automatically close when
temperatures return to normal. Limit rating will be on front side.
ECH26 VESTIBULE PARTS ARRANGEMENT
THERMAL
FUSE
PRIMARY
LIMIT
SEQUENCER
RELAY
2−Thermal Fuse F5
All ECH29 series units use a thermal fuse connected in series
with each element.The thermal fuse provides secondary high
temperature protection to each element. The thermal fuses are
non−resettable fusible links which must be replaced after being
tripped. Fuse rating will be on front side.
3−Electric Heat Sequencer Relays
K32, K33, K34
Relays K32, K33 and K34 are N.O. sequencer relays with a
resistive element for a coil and bi−metal disk which actuates the
contacts. The relays are located on the electric heat vest panel
and are energized by a 24V heating demand (W1 and W2) via
jack/plug P2 which is used to connect electric heat to the blow-
er control circuit. When energized, the internal resistance heats
the bi−metal disk causing the contacts to close. When the relay
is de−energized the disk cools and the contacts open. The re-
lays energize different stages of heat, as well as the blower.
The blower is always first on and last off.
4−Terminal Strip TB2 ECH29−05, −07, −10
For electric heat sections without circuit breakers or fuses, line
voltage connections are made to terminal strip TB2.
5−Heating Element HE1 through HE4
Heating elements are composed of helix−wound bare nich-
rome wire exposed directly to the air stream. The elements are
supported by insulators mounted to the wire frame. Each ele-
ment is energized independently by a corresponding relay lo-
cated on the heat vest panel. Once energized, heat transfer is
instantaneous.
Page 15
(ECH26−20 SHOWN)

ELECTRIC HEAT

ELEMENT
FIGURE 15
CIRCUIT
BREAKER