Williamson-Thermoflo GWC-070 Manual page 79

GWC -
gas fired water boiler
Troubleshooting
CHART 1
Electrical shock hazard — Wherever you see TURN OFF POWER, follow the instructions. Failure to follow
instructions could result in severe personal injury, death or substantial property damage.
Is POWER light off?
No
Is POWER light . . .
Flashing Flashing with
alone? another light?
TSTAT CIRC
light flashing
LIMIT
light flashing
PRESS SWITCH
light flashing
FLAME
light flashing
NO LIGHT IS
FLASHING,
but there is
insufficient heat
• Usually indicates polarity on incoming 120 VAC power
line is wrong.
• TURN OFF POWER at service switch or breaker, then
reverse the HOT and NEUTRAL wires entering the boiler
in the J-box.
• Restore POWER at service switch or breaker.
Is POWER light flashing now?
No
Boiler should now operate
normally.
Part number 550-142-056/0411
— Boiler Manual
(continued)
Troubleshooting POWER light status
Yes
On steady
(NOT flashing)?
CHART 2,
page 80
CHART 3,
page 81
CHART 4, CHART 6,
page 82 page 84
CHART 5, CHART 7,
page 83 page 85
CHART 8,
page 86
Yes
Have system checked by a
licensed electrician.
If problem persists, call your
local Williamson-Thermoflo
sales representative.
• Make sure service switch or circuit breaker is on or fuses
are good.
• Remove 120 VAC IN plug (Figure 89, page 76, Item 1) on
IBC.
• Using voltmeter, check across top and bottom pins
of 120 VAC IN receptacle.
Does voltmeter indicate 120 VAC?
No
Problem is with incoming
electricity. Have licensed
electrician repair circuit.
• Reconnect 120 VAC IN plug.
• Remove 120 VAC transformer PRIMARY plug
(Figure 89, page 76, Item 2) on IBC.
• Using voltmeter, check across top and bottom pins of PRI-
MARY receptacle.
Does voltmeter indicate 120 VAC?
No
Replace IBC.
Retest
• Reinstall 120 VAC transformer PRIMARY plug.
• Remove 24 VAC transformer plug (Figure 89, page 76,
Item 7) on IBC.
• Using voltmeter, check across pins of receptacle.
Does voltmeter indicate 24 VAC?
No
Replace transformer.
Retest.
Yes
Yes
Yes
Replace IBC.
Retest.
79