Weil-McLain 2 Series Manual page 85

series
GV90+
Troubleshooting
CHART 3
Electrical shock hazard — Wherever you see TURN OFF POWER, follow the instructions. Failure to fol-
low instructions could result in severe personal injury, death or substantial property damage.
• Reset boiler control by turning off power at service switch or
turning down thermostat for at least 45 seconds.
• Remove one wire and check Thermal switch on recuperator
and Block limit switch for continuity. If either switch is open,
Investigate the cause, correct and replace defective switch.
• Remove BLOWER plug (Figure 93, page
plug receptacle of IBC.
• Place voltmeter leads across the 120 VAC N and
120 VAC H pins of the BLOWER receptacle.
Does the voltmeter indicate 120 VAC?
No
• TURN OFF POWER at service switch.
Does blower wheel turn freely by hand?
No
• Properly position blower
wheel on blower motor
shaft and tighten set screw.
(Or replace blower housing
assembly.)
• Retest.
• Remove one of the red wires connected to the pressure
switch.
• Check continuity across the switch terminals.
Does the ohmmeter indicate the switch is closed?
No
• Replace IBC.
• Retest.
Part number 550-143-010/1021
gas-fired water boiler – boiler manual
2
(continued)
PRESS SWITCH & POWER lights flashing
Does blower motor operate?
No
80, Item 3) from
Yes
Yes
• Replace blower motor.
(Also check blower
housing assembly.
Replace if necessary.)
• Retest.
Yes
• Check air pressure switch per
• Replace if necessary.
• Retest.
• Thermostat should call for heat and appropriate zone valves
open.
Is blower wheel turning at speed of blower motor?
No
• TURN OFF POWER at
service switch.
• Properly position blower
wheel on blower motor
shaft and tighten set screw.
(Or replace blower housing
assembly.)
• Retest.
• Boiler should be in normal operating se-
quence (Figure 75, page
• Observe operation until thermostat is satis-
fied and blower has completed its post-
purge cycle.
• Check condensate trap.
Is blower wheel turning at speed of blower motor?
Is there condensate present?
No
No
Are vent or combustion air
passages blocked?
No
page 76.
• Clear passages and recycle boiler.
• Recheck boiler operation.
Yes
Yes
• Wait 5 minutes.
Is purge light flashing?
No
66).
Yes
Yes
• Drain condensate.
• Retest.
Yes
Yes
85