Harman® • PF-120 Installation Manual_R1 • 2014 -___ • 03/14
22
3-90-08121i
If installing a bulk hopper auger system:
The PF-120 has a pilot output that energizes when the low
fuel sensor is activated. See Wiring diagram below of Main
Junction Box.
This pilot output can operate a relay to start and stop the
bulk hopper auger motor.
Note:
These wires are to operate a relay ONLY.
Note:
Power for the bulk hopper auger motor CAN NOT be
taken from this junction box.
LOW FUEL PIL
O
T OUTPUT *
M
AIN JUNC
TION BO
X
10 A
MP CIR
CUIT BREAKER
POWER TO THE UPS *
120VAC 60 hz
BLACK
120VAC INPUT
TERMINALS
DRK BL
UE
WHITE
WHITE
GREEN
N
L
BROWN
DRK BL
UE
VIOLET
BR
OWN
BLACK
RED
BROWN
GREEN
WHITE
WHITE
GREEN
WHITE
BROWN
SK
Y BL
UE
WHITE
Figure 5.15
E. Installing Duct System
EXISTING
UNIT
Supply Duct
Return Duct
PF100
The pellet furnace warm air supply and the cold air return
must be installed in a parallel arrangement. EXAMPLE:
The warm air supply duct from the pellet furnace is to be
connected to the warm air supply of the existing furnace.
Also the cold air return duct from the existing furnace is to
be connected to the cold air return duct of the pellet furnace.
Isolation dampers (2) should be installed in the ductwork.
(1) in the warm air supply duct for the existing furnace and
(1) in the warm air supply duct of the pellet furnace after or
“downstream” of the high limit/fan control. These dampers
can be manually operated or fully automatic. In either case,
the unit that is not being used must be prevented from being
operated. (This also can be done manually or automatically.)
NOTE:
Any control wiring, power wiring needed should be
performed by a qualified installer and/or electrician.
The warm-air supply outlet of the pellet furnace shall not be
connected to the cold-air return inlet of the existing furnace
because of the possibility of overheating components of the
existing furnace, causing the existing furnace to operate
other than as intended.
We recommend that the warm air supply plenum be
constructed of sheet metal.
DO NOT USE DUCT ELBOwS HAVING AN INSIDE RADIUS
OF LESS THAN 150 MM (6 IN).
Add-on unit shall only be installed on a furnace duct
system and chimney that are in good operating condition.
The duct piping must be of metal construction in
accordance with NFPA 90B, 2-1.3.
Installing Duct
The pellet furnace may be connected to a gas or oil-fired
central furnace or heat pump duct system Figure 5.15.
Prior to installation, determine whether all requirements for
installation including all clearances can be met.
