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Part number 550-110-260/0508
44
GOLD CGs Gas-Fired Water Boiler — Boiler Manual
Troubleshooting — air pressure switch11b
Air pressure switch
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 offi ce for details.)
Boiler model number Inches W.C.
CGs-3 1.79"
CGs-4 1.48"
CGs-5 1.22"
CGs-6 0.95"
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 fl ue pipe or termination
• incorrect pressure switch
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.
The boiler will not operate cor-
rectly unless pressure switch
hoses are correctly located.
The red hose connects from
the right side (negative) hose
barb to the fl ue 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.