Weil-McLain ULTRA ULTRA-105 Service Manual page 27

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GAS FIRED WATER BOILER SERIES
Troubleshooting
Troubleshooting procedures — when display shows soft lockout code (continued)
SOFT LOCKOUT
25 Outlet water temp rose too quickly
— burner off for 10 minute wait
(burner recycles, increasing wait 1
minute each attempt, to a max of
15 minutes)
26 External limit open on limit wired
in soft lockout circuit (auto reset).
Low voltage terminals 6 and 7.
Burner off for 150 seconds
29 Blower signal not zero when it
should be — Burner off until signal
condition corrected
30 Temperature rise across boiler
more than 45°F. — Burner off for
150 second wait (plus 1 additional
minute for each failed attempt,
up to 20 times, then hard lockout
occurs
35 Short circuit across flue
temperature sensor terminals —
Burner off until corrected
40 Open circuit across flue
temperature sensor terminals —
Burner off until corrected
52 Flue Temperature exceeded 216 °F.
but did not exceed 225 °F (hard
lockout occurs above 225 °F —
Burner off for 150 second wait
65 Waiting for blower to start
Part number 550-100-029/0810
—
1 & 2
(continued)
[Display flashes 9, then b in first position; last two digits on steady (code)]
1 Possible hot water return from DHW tank.
2 Make sure system does not have trapped air preventing proper flow.
Inspect and verify system piping and components.
3
Verify piping agrees with boiler manual recommendations.
4
Verify proper circulator(s) operation.
5
Possible loose connector on boiler outlet sensor. Tighten connector.
6
7 Possible bad boiler supply outlet sensor.
1 If no external limit connected to 6 & 7, verify green jumper wire making good electrical
contact with screw terminals.
If external limit connected, verify proper limit operation.
2
Change display to Information mode — if INFO #6 shows 6._32, the blower has
1
failed.
2 Possible strong wind blowing against vent turning blower wheel, correct venting.
3 Defective blower.
4 Defective control module.
1 Flow problem through boiler — Temperature rise through boiler should be less than
35°F.
2 Make sure system does not have trapped air preventing proper flow.
3 Inspect and verify system piping and components (including pipe size and circulator
capacity).
Verify piping agrees with boiler manual recommendations.
4
5 Verify proper circulator(s) operation.
6 Possible loose connector on boiler supply/return sensor(s). Tighten connector.
7 Possible bad supply/return sensor — replace sensor.
1 Shorted wiring to flue sensor— correct the wiring.
2 Defective flue sensor — replace sensor.
Shorted wiring to flue sensor— correct the wiring.
1
Defective flue sensor — replace sensor.
2
1 Verify flue temperature with thermometer. If actual temperature does not correlate with
Information mode #5 replace flue sensor.
Heat exchanger may need to be cleaned. Follow the boiler maintenance procedure given
2
in this guide, page 33.
Burner problem — verify gas pressure, burner firing rate and combustion per Ultra
3
Boiler manual procedures — correct any problems.
If combustion is not acceptable, see page 38 in this guide.
1 Change display to Information mode — if INFO #6 shows 6._32, the blower has
failed.
2 Verify blower wiring, 120 VAC on high voltage connector, if no120VAC, inspect/replace
wire harness, or control module.
3 Defective blower.
4 Defective control module.
Instructions in this supplement are based
on factory default parameter settings.
27