Page 13
1−Condenser Fan
All 15CHAX units use single phase condenser fans. Specifica-
tions for the condenser fans are at the front of this manual. See
figure 12 for fan and motor replacement.
FIGURE
12
hub and shaft
should be flush
fan guard
1 1/2"
2−High Pressure Switch S4
S4 is a N.C. auto−reset high pressure switch located on the
liquid line. The switch shuts off the compressor when liquid
pressure rises above the factory setting. The switch on
15CHAX units is set to open at 590 + 10 psi and close at
418 + 10 psi.
3−Low Pressure Switch (S79)
The low pressure switch is an auto−reset N.C. switch that
opens on pressure drop. The switch is wired in series with
the high pressure switch S4 and compressor contactor
K1 and is located on the suction line . When suction pres-
sure drops to 10
psig
(68.95kPa)
the switch opens and the
compressor is de−energized. When suction pressure
rises to 30 psig
(206.85 kPa) the pressure switch will
close.
III−Electric Heat
A−Matchups and Ratings
Matchups and ratings are listed with ELECTRICAL DATA"
See table of contents.
B−Electric Heat Components
See figure 13 for electric heat parts arrangement.
1− Limit Switches 1, 2, 3 and 4
Limit switches 1, 2, 3and 4 are N.C. auto−reset high tempera-
ture limits located on the electric heat vest panel. Each heating
element is wired in series with a high temperature limit. When
the limit opens the corresponding heating element is de−ener-
gized. All other heating elements remain energized. The limits
will automatically close when temperatures return to normal.
Limit rating will be on front side.
2−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.
FIGURE 13
PHK VESTIBULE PARTS ARRANGEMENT
(PHK−10)
SEQUENCER
RELAY
PRIMARY
LIMITS
TB 2
3−Terminal Strip TB2 PHK−05, −07, −10
For electric heat sections without circuit breakers or fuses, line
voltage connections are made to terminal strip TB2.
4− Sequencer Relays 1 and 2
Relays 1 and 2 are N.O. sequencer relays with a resistive ele-
ment 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 blower
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.
5−Circuit Breaker CB1 and CB2 (option)
PHK−15, −20,
Line voltage connections are made to circuit breakers CB1 and
CB2 in electric heat sections with circuit breakers. Table 5
shows amp rating for each circuit breaker used. Two−pole cir-
cuit breakers are used.
TABLE 5
Circuit Breakers
UNIT
CB1 AMPS
CB2 AMPS
PHK15CP
60 AMPS
30 AMPS
PHK20CP
60 AMPS
60 AMPS
