Specifications magic-pak: hw/hwc, Refer to figure 2-1 – Armstrong World Industries HWC PREMIER 183 User Manual
Page 16
SPECIFICATIONS
Magic-Pak: HW/HWC
2-6
SRM-HW/HWC 2/99
Detailed Sequence - HWC123, 183, 243, 303
Refer to Figure 2-1
POWER
Line Voltage
With the unit at rest (no call from the
thermostat
), line
voltage will be present:
L1 Power
1.
Through the
L1
black lead to the
L1
terminal on the
ignition control
2.
At the
L1
contactor
terminal
3.
At the
transformer
terminal marked
208-240V
L2 Power
1.
Through the
L2
black lead to the
induced draft
blower
2.
At the
L2
contactor
terminal
3.
A
transformer
common terminal
4.
At the
T2
contactor
terminal
5.
At the
R
terminal of the
compressor
6.
At the
capacitor
common terminals
Low Voltage (24 VAC)
With the unit at rest (no call from the
thermostat
), 24
volts A/C will be present:
1.
From the
transformer
24V terminal to pin 4 of the
6-pin chassis low voltage harness
2.
From pin 4 of the chassis low voltage harness to the
24VAC
hot terminal on the
ignition control
3.
From the
24VAC
hot terminal to pin 5 of the 5-pin
thermostat harness (internal to board)
4.
From the
24VAC
hot terminal also to pin 6 of the 6-
pin ignition wire harness
5.
From pin 6 of the ignition wire harness through the
auto reset
limit switch
and the manual reset
rollout switch
to pin 1 of the 6-pin ignition wire
harness
Note: While the unit is at rest, the green LED shows
consistent slow flash. This indicates normal
operation - system at rest (standby mode).
CALL FOR HEAT
Line Voltage
The
ignition control
receives a signal from the
R-W
circuit indicating a call for heat.
1.
The
combustion blower
relay energizes, sending
L1
power to
CMB BLWR
terminal on the
ignition
control
. This causes the
combustion blower
to
start by completing the line voltage circuit through
the
L2
wire connection in the unit.
2.
As the 24-volt signal is sent to pin 4 of the 6-pin
ignition wire harness by the i
gnition control
, a 30-
second
circulating air blower
“on” delay starts.
After the delay, the
ignition control
energizes the
heat speed blower relay. This sends
L1
power to the
ACB HEAT
terminal on the
ignition control
.
3.
L1
power is then sent to the
circulating air blower
terminal block
where it is connected to the blower
motor. The
circulating air blower
starts by
completing the
L1-L2
circuit through the
L2
connec-
tion at the blower motor capacitor.
4.
The
combustion blower
and the
circulating air
blower
continue to run until the
R-W
circuit is
interrupted. After a 5-second post-purge delay, the
CMB BLWR
terminal on the
ignition control
de-
energizes. This interrupts L1 power to the
combus-
tion blower
. After a 120-second
circulating air
blower
“off” delay, the
ACB HEAT
terminal de-
energizes. This interrupts L1 to the
circulating air
blower
. As L1 power is interrupted, the blowers
shut off.
Low Voltage
1.
A call for heat closes the
R-W
circuit, sending a 24-
volt signal to the low voltage white wire in the unit.
2.
The 24-volt signal is received at pin 3 of the 5-pin
thermostat harness on the
ignition control
.
3.
The 24-volt signal causes the
combustion blower
relay to close, causing the
combustion blower
to
run. At this time, a 24-volt signal is also sent out
through pin 2 of the 6-pin ignition wire harness.
4.
The 24-volt signal from pin 2 of the 6-pin ignition
wire harness energizes one side of the Normally
Open
pressure switch
. As the
induced draft
blower
reaches full speed, the
pressure switch
closes and a 24-volt signal is sent to pin 5 of the 6-
pin ignition wire harness.
5.
When the 24-volt signal is received at pin 5 of the 6-
pin ignition wire harness, the
ignition control
starts
a 30-second pre-purge delay.
6.
After the 30-second pre-purge, the
ignition control
initiates a trial for ignition. The
spark ignition
cable
terminal and pin 4 of the 6-pin ignition wire
harness energize simultaneously.
7.
When the 24-volt signal is present at pin 4 of the 6-
pin ignition wire harness, the
ignition control
starts
a 30-second
circulating air blower
“on” delay.
8.
The 24-volt signal from pin 4 of the 6-pin ignition
wire harness is received at the
gas valve
, causing
it to open and the burners to ignite.