Install Instructions

Startup — final checks (continued)
Throttle screw adjustment
%#//.,9
$/./4 attempt to adjust the throttle screw unless by a quali-
fied 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 87.
1. Throttle screw adjustment is
ONLYNECESSARY when specified else-
where in this manual or when combustion tests indicate the need, as
explained under “❏#HECKmAMECOMBUSTIONWITHINSTRU-
MENTS,” page 78.
2. Boiler behavior that might indicate a need to check combustion values
at high fire (as per page 78) 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. Just check
the combustion values.
4. See Figure 87 for location of the
%#/ throttle screw.
&IGURE
%#/ Throttle screw (ONLY for use by a qualified
technician, using calibrated combustion test
instruments)
Gas inlet
PRESSURE
TESTPORT
4HROTTLEADJUSTMENTSCREW
Adjust the throttle screw in small movements.
5. See page 69 and Figure 77, page 70. Make sure the Max firing rate is set
to the maximum given in the table. If not, adjust as necessary. Then navi-
gate to DIAGNOSTICS — Manual test mode (see Figure 80, page 72)
and force the firing rate to HIGH (high fire). After the boiler has had
time to stabilize, take a CO
2
reading.
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.
6. Lock the boiler into low fire. Check the combustion readings. If results
are acceptable at low fire, verify high fire readings again. Restore firing
rate to AUTO. DO NOT adjust throttle on low fire.
7. Consult your local Weil-McLain representative if acceptable results
cannot be obtained for both high and low fire.
Boiler
MODEL
Fuel
(IGHlRE ,OWlRE
%
CO
2
CO
ppm
%
CO
2
CO
ppm
70
NG 9.25 +/ – 1.0 < 150 9.25 +/ – 1.0 < 50
LP 10.0 +/ – 0.5 < 150 10.0 +/ – 0.5 < 50
110
NG 9.25 +/ – 1.0 < 150 9.25 +/ – 1.0 < 50
LP 10.0 +/
– 0.5 < 150 10.0 +/ – 0.5 < 50
155
NG 9.25 +/ – 1.0 < 150 8.75 +/ – 1.0 < 50
LP 10.25 +/ – 0.5 < 150 9.75 +/ – 0.5 < 50
s 6ALUES ABOVE AREWITHTHEBOILER JACKET DOOR
REMOVED. Values will increase about 0.2% once the
jacket door is reinstalled.
s
2%).34!,, the boiler jacket door after completing
service.
s 6ALUESABOVEAREFORALTITUDESUPTOFEET&ORHIGHER
altitudes, CO
2
may be slightly lower and CO slightly
higher.
s Low fire CO
2
should be equal to or less than High fire CO
2
.
❏#HECKEXCHANGERANDVENTSEALS
1. Operate the boiler on HIGH fire.
2. Using an inspection mirror, move the mirror
around all heat exchanger joints and vent pipe
connections at the top of the boiler and at the con-
nection to the condensate dish.
3. A leak would appear as vapor on the surface of
the mirror.
4. If there is any indication of a leak at any joint, im-
mediately shut down the boiler.
a. If possible, tighten the retaining screws or nuts
(without over-tightening).
b. If this does not correct the problem, disassemble
the components where the leak appeared. Use
the procedures given in the Maintenance sec-
tion of this manual.
c. When disassembling components, inspect
gaskets to see if there is damage. Replace any
damaged gasket.
d. Contact your Weil-McLain representative if the
problem cannot be addressed with the informa-
tion provided in this manual.
5. Condensate dish joint
a. If the inspection mirror check shows a leak at
the condensate dish-to-heat exchanger joint,
contact your Weil-McLain representative for
instructions to correct the problem.
b. If the mirror test does not reveal a leak at the
condensate dish joint, but there are signs of
weepage or other indications that there might
be leakage, follow the procedure for checking
the heat exchanger-to-condensate dish seal on
page 99.
&IGURE Acceptable combustion values —
measured values must be within the
ranges given below
Part number 550-142-122/0513
81
TM
GAS-FIRED WATER BOILER — Boiler Manual