Low Draft Voltage Adjustment - Harman Stove Company XXV Installation & Operating Manual

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.

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
igniter operation. The XXV 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 unit's permanent installation conditions.
The control board on the XXV is equipped with a low draft
adjustment port. Located on the control face just to the left 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 change 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 efficiency is lost.
If the unit is adjusted too low, the low draft pressure switch
will not allow the feed motor or the igniter to operate.
3-90-00684R22_04/13
low draft Voltage adjustment
Fig.29
Draft Meter
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.
Neither pellets or a fire are required for this test.
3. With the mode selector in the "OFF" position, turn the feed
adjuster to "TEST".
4. Record the high draft_____in W.C. (Normal is -.50 to -.60)
The control will be on the High Draft for a total of 1 minute.
5. After 1 minute, 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 -.35 and -.45, 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: In some cases, the draft may not go as low as
-.35 to -.45 even with the set screw completely counter-
clockwise, ideally, you should just set it as low as
possible.
Draft Meter bolt hole location
is just behind the left front leg,
near the top of the ash pan area.
XXV Pellet Stove
17