Specifications

32
6.8 Mechanical Draft System for a Gas-red
Fireplace with multiple ues and Safety
System per NFPA54/IFGC
Application
This is used in the same situations as System 6,
but where multiple fans are required to handle the
exhaust volume. It is a typical installation for large
replaces where a single ue cannot handle the
amount of exhaust gases generated.
*For one fan serving two ues please refer to
section 6.6 as the wiring diagram is identical. A
special plenum box may be required.
Sequence of Operation
The fans should be wired in series and connected
to the ADC100. Each ue should be connected to a
separate proven draft switches and they should also
be connected in series.
1. During commissioning, the fan speed is set using
the potentiometer located on the ADC100
control board.
2. When the gas igniter is activated, the fan speed
increases. Once the proven draft switches
close, the fan returns to the speed setting of the
potentiometer and the ADC100 releases the
gas valve.
3. If proper draft is not maintained, the ADC100
will increase fan speed gradually until the PDS
closes. If both proven draft switches have
not closed 10 seconds after the fan reaches
100% speed, the ADC100 will shut off the gas
valve and go into alarm mode. If the PDS closes
while in alarm mode, the fan will resume the
original speed setting.
4. Once the replace is turned off, the fan will
continue to operate for a set post-purge time
(adjustable between 0-10 minutes) to remove any
remaining products of combustion before shutting
down.
5. In case of a mechanical or electrical failure the
ADC100 will shut off the gas valve.
System 8
Chimney
Fans
Chimney
Probe
Chimney
Probe
PDS
Proven Draft
Switch
ADC100
+/-
Gas-Fired Fireplace
RED ORANGE WHITE BLACK GREEN
FAN
MOTOR
120/1/60
NOTES:
THE DISCONNECT MEANS AND CIRCUIT PROTECTION ARE TO
BE PROVIDED BY THE INSTALLER OF THIS DEVICE
1
All wiring must be in
flexible or rigid metal
conduit
LEGEND:
24 VAC
120 VAC
N
L
FAN CONTROL UNIT
7 8 9 10 11 12 13 14 15 16 17 18 19
1 2 3 4 5 6
WEATHERPROOF BOX
MAIN CONTROL UNIT
6 5 4 3 2 1
All wiring must be in
metal conduit or
shielded cable