Specifications

36
Gas-Fired Fireplace
6.12 Mechanical Draft System for a Gas-red
Fireplace with Modulating Fan Speed and
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 ADC150. One ue should be connected to
one pressure switch and the other ue should be
connected to a separate proven draft switch.
1. During commissioning, the fan speed is set using
the potentiometer located on the ADC150
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 ADC150 releases the
gas valve.
3. If proper draft is not maintained, the ADC150
will increase fan speed gradually until the XTP2
closes. If both proven draft switches have
not closed 10 seconds after the fan reaches
100% speed, the ADC150 will shut off the gas
valve and go into alarm mode. If the XTP2 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
ADC150 will shut off the gas valve.
6. If two RS16s are used, an EBC12x should be
incorporated.
System 12
Chimney
Fans
Chimney
Probe
Chimney
Probe
PDS
Proven Draft
Switch
ADC150
+/-
XTP2
Pressure Switch
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