17
PART 3. GAS CONNECTION
G. GAS CONVERSION
If the appliance is to be converted in
the field for using Propane (LPG), the
following steps must be taken:
• Turn screw [1] clockwise (Figure
3-2
, page 15) ¾ of one turn (270°)
on models 299 and 1 full turn
(360°) on model HW399
• On model HW599 (
Figure 3-3
,
page 15) turn screw on left hand
valve closed (clockwise) and
turn right valve 1-¾ of a full turn
clockwise.
• Run the appliance. If the burner
does not ignite after four starting
efforts, turn the screw [1] one
half turn back (180°) (counter
clockwise).
• After conversion, follow the steps
in Sections E and F for setting the
maximum and minimum loads,
using the LP gas values shown in
Table
3-3
, page 17.
H. GAS VALVE MAINTENANCE/REPLACEMENT
1) When checking or replacing a
gas valve, the CO2 percentage
in the flue gas is the preferred
measuring method to insure
proper combustion and firing rate.
CO is used as the alternate.
2) Gas valve replacement for the
HW 599:
The left hand gas valve (which is
normally factory-set and sealed and
must not be adjusted) must be set
up to factory specifications before
any combustion related adjustments
can be performed on the right hand
valve. An electronic manometer must
be used, as it will be set to a scale of
0.01" WC.
The adjustment screw [1] (see
Figure 3-3, page 15) normally used
for setting maximum flow rate must
be turned counterclockwise until
it begins to click when turned. The
screw will not fall out, but will be fully
retracted at this point.
This is for
Natural Gas, for LP gas, close the
left hand valve (clockwise) until it
is closed down.
The digital manometer must now
be connected to the outlet pressure
tapping [4] on the left hand valve
only (marked do not adjust in Figure
3-3 page 15), and the appliance
fired. It must be placed in the service
mode and held at the minimum firing
rate (1653 rpm fan speed). With the
appliance firing at this rate, adjust
the offset (minimum firing rate)
screw [2] to a pressure of “0” +/-
.0.01" WC.
Be sure the manometer
has been zeroed out prior to
making this setting.
Once this operation is complete,
you may follow the instructions for
setting the minimum and maximum
firing rate as shown in Sections E
and F,
for the right hand gas valve
only.
FAILURE TO FOLLOW ALL PRECAUTIONS
COULD RESULT IN FIRE, EXPLOSION OR
DEATH!
WARNING
