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Part number 550-110-260/0200
42
GOLD CGs Gas-Fired Water Boiler
Troubleshooting — air pressure switch11b
Make sure boiler water temperature
is 100 °F or cooler before starting
procedure to obtain appropriate
readings.
Check pressure switch setting
1. See Figure 24 and Table 6.
2. Remove both air pressure switch hoses from air
pressure switch.
3. Install tees and tubing as shown in
Figure 24 to
inclined manometer.
4. Turn off gas valve and set thermostat to call for heat.
Inducer will run but burners will not ignite.
5. Check for 24 VAC between both air pressure switch
terminals and ground.
6. If manometer reading is above the setpoint of the
switch (see
Table 6), but there is not 24 VAC
between both air pressure switch terminals and
ground — replace air pressure switch.
Figure 24 Manometer connections
Table 6 Pressure switch setpoint
(for elevations above 2,000 ft, contact your
local Weil-McLain sales office for details.)
Suction
Pressure
Inclined tube
manometer
White
White
White
Flue collector
Interior panel
Rear
panel
Side
panel
Red
Red
Red
26035
Boiler model number Inches W.C.
CGs-3 1.79"
CGs-4 1.48"
CGs-5 1.22"
CGs-6 0.95"
The boiler will not operate correctly
unless pressure switch hoses are
correctly located. The red hose
connects from the right side
(negative) hose barb to the flue
collector. The white hose connects
from the left side (positive) hose
barb of the switch to the connector
box (between flue collector and
inducer) as shown in Figure 24.
Return to normal operation
When pressure reading is correct and air pressure
switch is operating properly — remove tees and
reinstall hoses to air pressure switch.
Troubleshooting air pressure reading
1. If manometer reading is lower than the setpoint
of the switch (see
Table 6) — check for possible
causes:
• blockage in hoses
• obstruction in inducer housing outlet
• loose inducer wheel on motor shaft
• inducer motor not in proper rpm
• inducer back plate not sealed properly
• blockage in block assembly
• blockage in flue pipe or termination
• incorrect pressure switch