Install Instructions
Part number 550-100-131/0715
– 89 –
™
GAS-FIRED WATER BOILER — Boiler Manual
Gas Valve Adjustment
$/./4 attempt to adjust the throttle or offset screw
unless done by a qualified technician, and with the use of
calibrated combustion test instruments. Adjust the throttle
or offset screw only as needed to meet the combustion val-
ues given in Figure 86. Must confirm correct low fire RPM
before making any adjustments to Offset regulating screw.
1. Throttle screw adjustment is ONLYNECESSARYif specified elsewhere
in this manual or if combustion tests indicate the need, as explained
under “#HECKmAMECOMBUSTIONWITHINSTRUMENTS,” page 88.
2. Boiler behavior that might indicate a need to check combustion values
at high fire (as per page 88) to verify boiler is in adjustment 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.
DO NOT attempt an adjustment of the throttle screw at low fire.
s See Figure 85 for location of the throttle screw. Remove the cover
screw to access the throttle adjustment screw.
Adjust the throttle adjustment screw in small movements.
&IGURE Throttle screw (ONLY for use by a qualified technician,
using calibrated combustion test instruments)
&IGURE Acceptable combustion values —
measured values must be within the ranges
given below
(IGH&IRE
Make sure the Max firing rate is set to the maximum and confirm the
rpm valve during operation given in the table Figure 93, page 98. If not,
adjust as necessary. Then navigate to DIAGNOSTICS — Manual test
mode (Figure 78, page 79) and force the firing rate to HIGH (maximum
output). After the boiler has had time to stabilize, take a CO
2
and CO
readings.
a. If the 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.
b. If the CO
2
is LOW, turn the throttle screw COUNTERCLOCKWISE
to increase the input. Allow the boiler to stabilize and take another
reading. Continue until the desired CO
2
value is achieved.
c. Confirm that the CO is within limits.
"OILER
MODEL
&UEL
(IGHlRE ,OWlRE
%
CO
2
CO
ppm
%
CO
2
CO
ppm
220
NG 9.25 ± 0.5 < 100 8.75 ± 0.5 < 50
LP 10.75 ± 0.5 < 120 10.25 ± 0.5 < 50
299/300
NG 9.25 ± 0.5 < 100 8.75 ± 0.5 < 50
LP 10.75 ± 0.5 < 120 10.25 ± 0.5 < 50
399
NG 9.25 ± 0.5 < 100 8.75 ± 0.5 < 50
LP 10.75 ± 0.5 < 120 10.25 ± 0.5 < 50
s 6ALUES ABOVE ARE WITH THE BOILER FRONTDOOR REMOVED.
Values will increase about 0.2% once the door is reinstalled.
s 2%).34!,, the boiler door after completing service.
s 4HELOWlRE#/
2
listed is typical. The valve may vary with conditions,
but must be 0.35% to 0.75% lower than the high fire CO
2
value.
Low Fire
1. Adjust the boiler to (LOW) (minimum output) and allow the
boiler to stabilize. Confirm the rpm valve during operation
with the table Figure 93, page 98.
2. Remove the slotted cap, see Figure 85, for Offset screw
adjustment.
a. If the CO
2
is HIGH, turn the offset regulating screw
COUNTERCLOCKWISE to lower the input. Allow the
boiler to stabilize and take another reading. Continue until
the desired CO
2
value is achieved.
b. If the CO
2
is LOW, turn the regulating screw CLOCKWISE
to increase the input. Allow the boiler to stabilize and take
another reading. Continue until the desired CO
2
value is
achieved.
c. Confirm that the CO is within limits.
Re-check the Maximum and Minimum
CO
2
and CO rate
1. Turn off the boiler and then turn it back on and put in Test
Mode at maximum. Ensuring the CO2 setting level has re-
mained unchanged and confirm that CO is within limits.
2. Reduce to minimum and re-check the minimum rate
output ensuring the CO2 setting level has remained
unchanged and confirm that CO is within limits.
3. In the event that the CO2 and CO cannot be ob-
tained, please contact your Weil-McLain representative.
4. Should you require any assistance during the set up procedure
contact your Weil-McLain representative if the problem cannot
be addressed with the information provided in this manual.
❏#HECKIGNITIONSYSTEMSAFETYSHUTOFFDEVICE
1. After the boiler has been installed, turn off the boiler.
2. Shut off the manual gas valve located on the gas line to stop
flow of fuel to the boiler.
3. Turn on the boiler. It will start the ignition sequence, but will
not light. After some time, the boiler will lockout, the display
screen will turn red, and the Control will flash “Ignition Fault”.
It means that the boiler tried to ignite without success for five
(5) times and went into Lockout mode. This means that the
ignition system safety device worked properly.
4. Clear the Lockout condition by selecting “Manual Reset” in
the Diagnostic Menu.
5. Open the manual gas valve located on the gas line to resume
fuel supply to the boiler.
Startup — final checks (continued)
'AS)NLET0RESSURE
4EST0ORT
Offset Regulating screw
sTurn clockwise
to increase CO
2
.
sTurn counter-clock-
wise to decrease CO
2
.
1RWH0XVWUHPRYHFRYHU
Throttle adjustment screw
sTurn counter-clockwise
to increase CO
2
.
sTurn clockwise to
decrease CO
2
.