Optional Electric Heat (Ecb40); Matchup And Ratings; Electric Heat Components; J49 Test - Lennox CBX32MV-018/024 Manual

P48 (5-PIN)
HARNESS
MOTOR

Optional Electric Heat (ECB40)

A-MATCHUPS AND RATINGS
The tables on the following pages show all approved
CBX32MV to ECB40 matchups and electrical ratings.
B-ELECTRIC HEAT COMPONENTS
ECB40 parts arrangement is shown in figure 38. All electric
heat sections consist of components mounted to the electric
heat vestibule panel and electric heating elements exposed
directly to the air stream. ECB units are equipped with circuit
breakers or a terminal blocks. The circuit breakers are
designated by CB in the model number.
1. Primary (S15) and Secondary (S20) Temperature
Limits
Each stage of the electric heat is protected by a
primary (S15) and secondary (S20) high temperature
limit. Both S15 and S20 are located in the same housing.
Each stage uses the same style of limits. Both the primary
and secondary limits are wired in series with a heat
element. When either S15 or S20 opens, the
corresponding heat element is de‐energized. All
other heating elements remain energized. The primary
high temperature limit opens on a temperature rise and
closes on a temperature fall. The secondary limit opens on
a temperature rise but must be replaced. See table 17 for
set points.
TABLE 17
Limit Open°
S15 150_F + 5
S20 333_F + 10_F
2. Electric Heat Relays (K32, K33, K34, K35 and K36)
Relays K32, K33, K34, K35 and K36 are N.O. relays
located on the electric heat vestibule panel and are
energized by a 24V heating demand (W1, W2, and W3)
via jack/plug 2 (J2), which is used to connect electric heat
to the blower coil control circuit. The relays energize
different stages of heat, as well as the blower. The
blower is always first on and last off.
CBX32MV
P49 (4-PIN) HARNESS
J49 4 Pin
CONTROL MODULE
Figure 37. J49 Test (Emerson)
Close°
110 + 9
Replace limit
Page 66
24v Transformer
3. Terminal Strip (TB2)
For the electric heat sections without circuit breakers or
fuses, line voltage connections are made to terminal strip
TB2. The terminal strip is located in the lower left corner of
the electric heat vestibule panel. Single‐phase electric
heat uses two pole terminal strips; while three‐phase
electric heat uses three pole terminal strips.
4. Circuit Breaker (CB1, CB2 and CB3)
Line voltage connections are made to circuit breakers
CB1,CB2 and CB3 in the electric heat sections with circuit
breakers (designated by CB in the model numbers).
Tables in the following pages show the amp rating for each
circuit breaker used. Single‐phase electric heat uses two
pole circuit breakers; while three‐phase electric heat uses
three pole circuit breakers.
NOTE - Electric Heat Circuit Breakers are sized for 240VAC
operation. Electric heaters operating at voltages other than
240VAC may require the factory installed circuit breaker be
replaced with a field installed circuit breaker. See
Maximum Overcurrent Protection column in the Electric
Heat Tables to determine if a circuit breaker change is
required.
NOTE - Do not remove patch plate or insulation on units
without circuit breakers!!
5. Heating Elements (HE1 through HE6)
Heating elements are composed of helix wound bare
nichrome wire exposed directly to the air stream. The
elements are supported by insulators mounted to the wire
frame. For single phase applications, one element is
used per stage.
independently by the corresponding relay located
on the electric heat vestibule arranged in a three
phase delta. Once energized, heat transfer is
instantaneous. High temperature protection is
provided by primary
temperature limits.
P48 (5-PIN)
HARNESS
J49 Connector
Each stage is energized
and secondary high