Installation Guide

Part number 550-100-066/0608
75
g a s -f i r e d w at e r b o i l e r — Boiler Manual
Startup — final checks (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.
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 85, page 64) and force the firing rate to MIN (low fire).
Look at the ame through the ame inspection window. The low 9.
fire ame 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 85, page 64) and force the firing rate to AUTO (normal
operation).
Replace the ue gas temperature sensor.12.
You must replace the ue gas temperature sensor to
prevent ue gas spillage into the boiler enclosure. Failure
to comply could result in severe personal injury, death
or substantial property damage.
Throttle screw adjustment procedure
DO NOT attempt to adjust the throttle screw unless by
a qualified technician, and with the use of calibrated
combustion test instruments. Adjust the throttle screw
only as needed to meet the combustion values given in
Figure 88.
This procedure is only necessary when combustion tests indicate 1.
the need, as explained under “ Check flame & combustion
with instruments, page 74.”
Boiler behavior that might indicate a need to check combustion 2.
values at high fire (as per page 74) to verify boiler is in adjustment
include: difficulty igniting, poor ame stability at low fire, combus-
tion noise or high carbon monoxide values.
Combustion readings must be taken at both high fire and low fire. 3.
DO NOT attempt an adjustment of the throttle screw at low fire.
Just check the combustion values.
Use the U-Control display to navigate to Manual test mode (see 4.
Figure 85, page 64) and force the firing rate to MAX (high fire).
After the boiler has had time to stabilize, take a CO
2
reading.
If the a. CO
2
is HIGH, turn the throttle screw CLOCKWISE to
lower the input. Allow the boiler to stabilize and take another
reading. Continue until the desired CO
2
value is achieved.
If the b. CO
2
is LOW, turn the throttle screw COUNTERCLOCK-
WISE to increase the input. Allow the boiler to stabilize and
take another reading. Continue until the desired CO
2
value is
achieved.
Lock the boiler into low fire. Check the combustion readings. If 5.
results are acceptable at low fire, verify high fire readings again.
Restore firing rate to AUTO.
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

Consult your local Weil-McLain representative if ac-6.
ceptable results cannot be obtained for both high and
low fire.
 Adjust and test boiler controls
Follow instructions in this manual to set and verify 1.
operation of the boiler controls.