Gas Valve Adjustment Procedure - Weil-McLain Ultra Commercial Installation And Start-Up Manual

COMMERCIAL GAS
Startup — final checks
7. Measure natural gas input:
a. Operate boiler 10 minutes.
b. Turn off other appliances.
c. At natural gas meter, measure time (in seconds) required to
use one cubic foot of gas.
d. Calculate gas input:
3600 x 1000
number of seconds from step c
e. Btuh calculated should approximate input rating on boiler
rating label.
8. Use the U-Control display to navigate to Manual test mode (see
Figure 65, page 63) and force the firing rate to MIN (low fire).
9. Look at the flame through the flame inspection window. The low
fire flame should be stable and evenly distributed over burner
surface with a uniform orange color.
10. Repeat the combustion test of steps 5 and 6 above.
11. Use the U-Control display to navigate to Manual test mode (see
Figure 65, page 63) and force the firing rate to AUTO (normal
operation).
12. Re-install the flue gas temperature sensor.
You must re-install the flue gas temperature sensor to
prevent flue gas spillage into the boiler enclosure. Failure
to comply could result in severe personal injury, death
or substantial property damage.

Gas valve adjustment procedure

DO NOT attempt to adjust the gas valve settings un-
less you are a qualified technician, and with the use of
calibrated combustion test instruments. Adjust the valve
settings only as needed to meet the combustion values
given in Figure 68.
1. This procedure is only necessary when combustion tests indicate
the need, as explained under "
with instruments, page 73."
2. Boiler behavior that might indicate a need to check combustion
values at high fire (as per page 73) to verify boiler is in adjustment
include: difficulty igniting, poor flame stability at low fire, combus-
tion 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. Use the U-Control display to navigate to Manual test mode (see
Figure 65, page 63) and force the firing rate to MAX (high fire).
After the boiler has had time to stabilize and high-fire RPM value
(see Figure 74, page 82) is reached, take a CO
a. See Figure 69 to adjust if necessary.
b. Remove the blue cover on the throttle screw opening with a
straight-bit screwdriver.
Make only small (1/8-turn) throttle screw adjustments.
Adjustment can be sensitive, especially on propane.
c. If the CO is HIGH, turn the throttle screw CLOCKWISE to
2
lower the input. Allow the boiler to stabilize and take another
74
-
FIRED WATER BOILER
(continued)
= Btuh
Check flame & combustion
reading.
2
— Boiler Manual
Throttle screw location (ONLY for use by
a qualified technician, using calibrated
combustion test instruments)
reading. Continue until the desired CO
achieved.
d. If the CO is LOW, turn the throttle screw COUN-
2
TERCLOCKWISE to increase the input. Allow the
boiler to stabilize and take another reading. Con-
tinue until the desired CO
e. Re-install the blue cover on the gas valve.
Adjust valve at low fire
1. Lock the boiler into low fire using the U-Control module
screen. Verify that the blower rpm value is correct for
low fire (see Figure 74, page 82).
2. Check the combustion readings.
3. If results are acceptable at low fire, verify high fire read-
ings again. Restore firing rate to AUTO.
4. If combustion results are not acceptable, remove the
cover screw over the offset adjustment (see Figure 69).
5. Use a T40 Torx driver to adjust the setting. Rotate clock-
wise to increase CO
CO . Re-install the cover screw when completed.
2
6. Consult your local Weil-McLain representative if ac-
ceptable results cannot be obtained for both high and
low fire.
Adjust and test boiler controls
1. Follow instructions in this manual to set and verify
operation of the boiler controls.
value is
2
value is achieved.
2
, rotate counterclockwise to decrease
2
Part number 550-100-086/0809