Weil-McLain ULTRA Ultra-105, Service Manual, Page: 39 / 60

39
Part number 550-100-029/0810
GAS
-
FIRED WATER BOILER SERIES
1 & 2
—
Control supplement & Service guide
Combustion testing and adjustment
(continued)
Measure natural gas input: 7.
Operate boiler 10 minutes. a.
Turn off other appliances. b.
At natural gas meter, measure time (in seconds) required to c.
use one cubic foot of gas.
Calculate gas input:
d.
3600 x 1000
number of seconds from step
c
= Btuh
Btuh calculated should approximate input rating on boiler e.
rating label.
Press and hold the Ultra control panel “Mode” and “-” buttons 8.
simultaneously until the display shows “L”.
The “L” in the first digit means the boiler will operate at low fire
9.
when the blower speed reaches minimum.
Look at the flame through the flame inspection window. The low
10.
fire flame should be stable and evenly distributed over burner
surface with a uniform orange color.
Test for CO
11.
2
(or O
2
) and for CO. The CO
2
values must be within
1.0% of the values listed in Figure 24, page 40.
If results are acceptable, proceed to step . a.
IF NOT, follow the instructions under b. “Throttle screw adjust-
ment procedure”, page 40, to set the throttle screw position.
See WARNING below.
If combustion at either high or low fire is outside
the range given in Figure 24, page 40, follow the
procedure given on page 40 for adjusting the throttle
screw on the venturi. If throttle screw adjustment
does not correct the problem, then shut down the
boiler and contact your local Weil-McLain repre-
sentative. Throttle screw adjustment must be done
only by a qualified technician, using calibrated test
instruments. Failure to comply could result in severe
personal injury, death or substantial property dam-
age.
If combustion test results at high fire and low fire are correct, press 12.
and hold the “+” and “-” buttons to return boiler to automatic
firing.
Re-install the flue gas temperature sensor. When inserting the
13.
sensor, remove the rubber grommet from the probe. Insert the
rubber grommet into the flue pipe, then insert the probe into the
rubber grommet.
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.
Re-install boiler jacket front door after servicing. The
boiler front door must be securely fastened to the boiler
to prevent boiler from drawing air from inside the boiler
room. This is particularly important if the boiler is lo-
cated in the same room as other appliances. Failure to
keep the door securely fastened could result in severe
personal injury or death.
-ODELSˆ4HROTTLESCREW
&IGURE
LOCATION/.,9FORUSEBYAQUALIlED
TECHNICIANUSINGCALIBRATEDCOMBUSTION
TESTINSTRUMENTS
ˆ3EEPREVIOUSPAGEFOR5LTRAORˆ