Harman Stove Company PC 45 Installation And Operating Manual page 18

Fig.29
Low Draft Voltage Adjustment
These units are pre-tested at the factory with
exactly 120 Volts A.C., 60 Hz. They are checked and
adjusted for firebox tightness, gasket leakage, motor
operation and ignitor operation. The PC 45 is then
factory set at a mid-point adjustment and in most
cases will not need any adjustments. NOTE: The
factory low draft setting may not be correct for
the units permanent installation conditions.
The control board on the PC45 is equipped
with a low draft adjustment port. Located on the
control face just to the right of the igniter light. This
voltage adjustment is provided to allow the unit to be
adjusted for the household voltage where the unit is
going to be in permanent operation. NOTE: The line
voltage varies from area to area and often home to
home.
The low draft voltage should be adjusted to
achieve the most efficient burn on low burn or
"maintenance". This voltage adjustment allows the
installer to c hange the low voltage set point
approximately 10 volts. This adjustment should be
done by the installer during set up because a draft
meter reading is required to insure proper set up.
If the unit is not adjusted properly, it does not
cause a safety concern. If the unit is adjusted too
high, only effiency is lost. If the unit is adjusted too
low, the low draft pressure switch will not allow the
feeder motor or the igniter to operate
18 PC 45 Corn/Pellet Stove
Low Draft Voltage Adjustment
Combustion Motor
Speed Control
Low draft only set
point.
The small straight
screwdriver slot is
plastic; therefore, the
unit can be adjusted
while in operation.
.
Dr aft M ete r bo lt
hole location
On a PC 45 the draft
hole is under the left
rear corner of the
firebox.
Fig. 30
A simple draft test should be performed after
completing the flue pipe installation. To record the
results for future reference:
1. Plug unit into a 120VAC, 60 HZ outlet.
2. Close the hopper lid, front view door, and the ash
pan access door. Neither fuel or a fire are required
for this test.
3. W ith the mode selector in the "OFF" position,
turn the feed adjuster to "TEST".
4. Record the high draft_____in W.C. (Normal is
-.35 to -.55) The control will be on the High Draft for
a total of 2 minutes.
5. After 2 minutes is up, the combustion motor will
go down to low draft and the distribution blower will
go on high. Allow approximately 15 seconds to pass
for the combustion motor to slow before checking
the low draft.
6. If the low draft is between -.25 and -.35, record
the reading _____ in W.C. If the reading is higher,
slowly turn the set screw counter-clockwise until the
draft lowers. If the reading is lower, very slowly turn
the set screw clockwise until the draft increases.
NOTE: The test mode alternates from high to
low draft every 60 seconds. If more time is
needed for draft adjustment, wait until the next
low draft cycle.
NOTE: In some cases, the draft may not go as
low as -.25 to -.35 even with the set screw
completely counter-clockwise. This is not a
problem.