Specifications

Part number 550-100-090/0809
g a s -f i r e d w a t e r b o i l e r — Boiler Manual
36
Startup — final checks (continued)
 Check flame & combustion with instruments
For Ultra-399 propane boilers, special start-up is re-
quired. See page 37 for procedure. See DANGER on
page 45 before proceeding.
Initiate a call for heat on one of the heat demand inputs.1.
Access the U-Control installer menus by pressing and holding the 2.
UP and DOWN arrow keys for five seconds.
Use the U-Control display to navigate to Manual test mode (see 3.
Figure 102, page 86) and force the firing rate to MAX (high fire).
Look at the flame through the flame inspection window. The high 4.
fire flame should be blue and should be stable. The burner surface
should be covered with orange dots.
Remove the flue temperature sensor from the flue pipe and in-5.
sert a combustion test probe., using a calibrated combustion test
instrument.
Test for CO6.
2
(or O
2
) and for CO. The CO
2
values must be within
1.0% of the values listed in Figure 40. If results are acceptable,
proceed to step 7. IF NOT, follow the instructions under “Throttle
screw adjustment procedure” to set the throttle screw position. See
WARNING below.
If combustion at either high or low fire is outside the
range given in Figure 40, follow the procedure given
on page 37 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 representative. 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 damage.
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.
Btuh calculated should approximate input rating on boiler e.
rating label.
Use the U-Control display to navigate to Manual test mode (see 8.
Figure 102, page 86) and force the firing rate to MIN (low fire).
Look at the flame through the flame inspection window. The low 9.
fire flame should be stable and evenly distributed over burner
surface with a uniform orange color.
Repeat the combustion test of steps 4 and 5 above.10.
Use the U-Control display to navigate to Manual test mode (see 11.
Figure 102, page 86) and force the firing rate to AUTO (normal
operation).
Replace the flue gas temperature sensor. When replacing the sen-12.
sor, remove the rubber grommet from the probe. Insert the rubber
Models 80 & 105 — Throttle screw Figure 37
location (ONLY for use by a qualied
technician, using calibrated combustion
test instruments)
Models 155, 230 & 299 — Throttle screw Figure 38
location (ONLY for use by a qualied
technician, using calibrated combustion
test instruments)