Gas Valve Adjustment Procedure - Weil-McLain SlimFit Manual

SlimFit
™
commercial condensing gas
Startup procedure
If combustion at either high or low fire is outside
the range given in Figure 89, follow the procedure
given for adjusting the throttle screw on the gas
valve. If throttle screw adjustment does not cor-
rect the problem, then shut down the boiler and
contact your local Weil-McLain representative.
Throttle screw adjustment must be done only by
a qualified technician, using calibrated test instru-
ments. Failure to comply could result in severe
personal injury, death or substantial property
damage.
Figure 89
Acceptable CO
High fire
Boiler
%CO
2
Note 1
SF1000 9 00
SF1500 9 00
SF2000 9 00
The high fire CO
Note 1 vary with conditions, but must not be lower than
8.5% nor higher than 10.0%.
The low fire CO
vary with conditions, but must not be higher than
Note 2
the high fire CO
high fire CO .
2
Figure 90
Gas valve adjustment locations
for use by a qualified technician, using
calibrated combustion test instruments)
Throttle screw
adjustment (high fire)
Offset adjustment
(low fire)
Part number 550-100-116/0713
(continued)
and CO values
2
Low fire
CO %CO CO
2
ppm ppm
Note 2
< 60 8 75 < 60
< 60 8 75 < 60
< 60 8 75 < 60
listed is typical. The value may
2
listed is typical. The value may
2
nor more than 0.5% less than the
2
(ONLY
Solenoid indicator
lights (V1 & V2)
-
fired water boiler
You must re-install the flue gas sample port cover to
prevent flue gas spillage into the boiler room. Failure
to comply could result in severe personal injury, death
or substantial property damage.

Gas valve adjustment procedure

DO NOT
less you are a qualified technician, and with the use
of calibrated combustion test instruments. Follow
instructions in this section.
DO NOT adjust or attempt to the measure gas
valve outlet pressure
for the correct outlet pressure, requiring no field
adjustment. Attempting to alter or measure the gas
valve outlet pressure could result in damage to the
valve, causing potential severe personal injury, death
or substantial property damage.
1. This procedure is only necessary when combustion tests
indicate the need
2. Boiler behavior that might indicate a need to check combustion
values at high fire (as per page 90) to verify boiler is in adjust-
ment include: difficulty igniting, poor flame stability at low fire,
combustion noise or high carbon monoxide values.
3. Combustion readings must be taken at both high fire and low fire.
Adjust valve at high fire
1. Manually set the boiler to high fire (see Figure 87). Perform
combustion test as described at left.
a. Remove the blue cover on the throttle screw opening with a
straight-bit screwdriver.
For the following, make only small (1/8-turn) throttle
screw adjustments. Adjustment can be sensitive. Use a
3-mm hex wrench.
b. If the CO is HIGH, turn the throttle screw CLOCKWISE to
2
lower the input. Allow the boiler to stabilize and take another
reading. Continue until the desired CO
c. If the CO
2
CLOCKWISE to increase the input. Allow the boiler to
stabilize and take another reading. Continue until the desired
CO value is achieved.
2
d. Re-install the blue cover on the gas valve.
Adjust valve at low fire
1. Manually set the boiler to low fire (see Figure 87). Perform com-
bustion test as described at left.
2. If results are acceptable at low fire, verify high fire readings again
and restore the boiler to automatic operation.
3. If combustion results are not acceptable, remove the cover screw
over the offset adjustment (see Figure 90).
a. Use a T40 Torx driver to adjust the setting. Rotate clockwise
to increase CO
Re-install the cover screw when completed.
b. After making an adjustment, go back to check high fire. If the
adjustment on low fire is large enough it can impact the high
fire setting. The process may need to be repeated.
4. Consult your local Weil-McLain representative if acceptable
results cannot be obtained for both high and low fire.
— Boiler Manual
attempt to adjust the gas valve settings un-
The gas valve is factory-set
.
value is achieved.
2
is LOW, turn the throttle screw COUNTER-
, rotate counterclockwise to decrease CO
2
.
2
91