Troubleshooting - Weil-McLain Ultra Manual

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gas fired water boiler

Troubleshooting

Label all wires prior to disconnection when servic-
ing controls. Wiring errors can cause improper and
dangerous operation. Always disconnect power to
boiler before servicing. Failure to comply could
result in severe personal injury, death or substantial
property damage.
Electrical shock hazard
switch does not turn off all power to the boiler.
Internal wiring is still powered when the switch is
off.
Never jumper (bypass) any device except for mo-
mentary testing. Severe personal injury, death or
substantial property damage can result.
Reinstall boiler jacket front door
Reinstall boiler jacket front door after servicing.
The boiler front door must be securely fastened to
the boiler to prevent boiler from drawing air from
inside the boiler room. This is particularly important
if the boiler is located in the same room as other ap-
pliances. Failure to keep the door securely fastened
could result in severe personal injury or death.
Before troubleshooting:
1. Have the following items:
a. Voltmeter that can check 120 VAC , 24 VAC and 12 VDC.
b. Continuity checker.
c. Contact thermometer.
2. Check for 120 VAC (minimum 102 VAC to maximum 132 VAC)
to boiler.
3. Make sure thermostat is calling for heat and contacts (including
appropriate zone controls) are closed. Check for 24 VAC between
thermostat wire nuts and ground.
4. Make sure all external limit controls are either installed (and closed)
or temporarily jumpered for testing.
Check the following:
1. Wire connectors to control module are securely plugged in at
module and originating control. See Figure 96, page 87 for wire
harness information.
2. Gas pressures:
• Maximum: 13" w.c. with no flow (lockup) or with boiler on
• Minimum: 5" w.c. for natural gas, or 4" w.c. for propane,
with gas flowing (verify during boiler startup with boiler at
high fire)
VERIFY PROPER OPERATION AFTER SERVICING.
84
— Boiler Manual
— The boiler ON/OFF
3. Navigate the U-Control's Diagnostics menus to check
both lockout and current conditions.
Always check control module fuses
ALWAYS check control module fuses before
replacing control module or any major com-
ponents (blower, etc.). If one of these fuses is
blown, it can prevent control module or other
components from operating.
1. Turn OFF power to boiler at external line switch.
2. Remove jacket door and jacket top panel. Rotate the
swing-away control panel forward to expose the U-
Control module.
3. Remove and inspect the two fuses (located as shown
below).
4. If necessary, replace the fuse:
a. Low voltage circuit fuse is 3-amp fast-blow
(Littelfuse 326012P).
b. Line voltage circuit fuse is 12-amp slow-blow
(Littelfuse 257003).
Do not jumper fuse or replace with any fuse
except as specified. Failure to comply could
result in severe personal injury, death or sub-
stantial property damage.
5. Reinstall jacket top panel and boiler jacket door after
checking the fuses.
6. Restore power to boiler at external line switch and verify
boiler operation after completing boiler service.
Part number 550-100-066/0608