Williamson Series 2 - Troubleshooting

31
Part Number 550-142-785/0812
GWI Series 2 Gas-Fired Water Boilers – Boiler Manual
12 Troubleshooting
 Labelallwirespriortodisconnectionwhenservic-
ing controls. Wiring errors can cause improper and
dangerous operation.
 Neverjumper(bypass)rolloutthermalfuseelement
oranyotherdeviceexceptformomentarytestingas
outlinedin“Troubleshooting”charts,pages 34 - 40.
Severe personal injury, death or substantial property
damage can result.
Burner access panel must be in position during
boiler operation to prevent momentary flame rollout
onignitionofmainame.Severepersonalinjuryor
substantial property damage will result.
Before troubleshooting:
1. Havethefollowingitems:
a. Voltmeterthatcancheck120VACand24VAC.
b. Microammeterwithaminimumscalerangeof0-25.
c. Continuitychecker.
d. U-tubemanometer
e. Inclinedmanometerwith0–2”w.c.range.
2. Checkfor120VAC(minimum102VACtomaximum132VAC)
to boiler.
3. Makesurethermostatiscallingforheatandcontacts(includ-
ingappropriatezonecontrols)areclosed.Checkfor24VAC
between thermostat wire nuts and ground.
Check the following:
1. Wire connectors to control module are securely plugged in at
module and originating control.
2. Gaspressures(connectU-tubemanometeratgasvalvetap-
pings):
a. Withboileroff—13”w.c.maximumnaturalorpropane
gaspressureupstreamofgasvalve.
b. With boiler on:
• 5”w.c.minimumnaturalgaspressureor11”w.c.propane
gaspressureupstreamofgasvalve.
• 3.5”w.c.minimumnaturalgaspressureor10”w.c.propane
gaspressuredownstreamtappingongasvalve—Can
be adjusted by regulator on gas valve.
How to check pressure switch setting (if specified
in Troubleshooting charts
)
 Make sure boiler water temperature is 100 °F or
coolerbeforestartingproceduretoobtainappropri-
ate readings.
1. See Figure 21 and Table 9.
2. Removeboth air pressure switchhoses from air pressure
switch.
3. Install tees and tubing as shown in Figure 21 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.
6. Ifmanometerreadingisabovethesetpointoftheswitch(see
Table 9),butthereisnot24VACbetweenairpressureswitch
terminals“C”and“NO”—replaceairpressureswitch.
Troubleshooting air pressure reading
1. Ifmanometerreadingislowerthanthesetpointoftheswitch
(seeTable 9)—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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 correctly unless pressure
switch hoses are correctly located. The red hose
connectsfromtherightside(negative)hosebarb
totheuecollector.Thewhitehoseconnectsfrom
theleftside(positive)hosebarboftheswitchtothe
connectorbox(betweenuecollectorandinducer)
as shown in Figure 21.
Table 9 Pressure switch setpoint (for elevations
above 2,000 ft, contact your local supplier for
details.)
Boiler model number Inches W.C.
GWI-047 and GWI-063
1.19
GWI-095
1.08
GWI-127
0.86
GWI-158
0.61
GWI-190
0.76
Figure 21 Checking pressure switch