Lochinvar Shield SNA285-125 - Manual (Page 58)

58
13
Troubleshooting
Label all wires prior to disconnection
when servicing controls. Wiring errors
can cause improper and dangerous
operation. Always disconnect power to
the water heater before servicing.
Failure to comply could result in severe
personal injury, death, or substantial
property damage.
Never jumper (bypass) any device
except for momentary testing as
outlined in the Troubleshooting chart.
Severe personal injury, death, or
substantial property damage can result.
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 water heater.
3. Make sure the tank is calling for heat.
4. Make sure all external limit controls are installed and
operating.
Check the following:
1. Wire connectors to control module and connection
board are securely plugged in.
2. Gas pressures:
• Maximum: 14 inches w.c. (natural and LP) with no
flow (lockup) or with water heater on
• Minimum: 4 inches w.c. (natural), 8 inches w.c. (LP)
with gas flowing (verify during water heater startup)
Check control module fuses
ALWAYS check control module fuses before
replacing control module or any major
components (blower, etc.). If one of these
fuses is blown, it can prevent the control
module or other components from
operating.
1. Turn OFF power to the water heater at the external
disconnect switch.
2. Remove top access cover.
3. Remove the control module cover.
4. Inspect fuses F2, F3, F4, and F5, see FIG. 13-1 below.
F4 - 3.15 AMP FUSE
GAS VALVE
F3 - 1.25 AMP FUSE
MAIN BOARD
F5 - 5 AMP FUSE
PUMPS
F2 - 3.15 AMP FUSE
24V SUPPLY
Figure 13-1 Control Module Fuses
5. The water heater is shipped with three (3) spare fuses in a
plastic bag attached to the control module cover.
6. If necessary, replace open fuse (F3 is 1.25 amps, F2 and F4
are 3.15 amps, and F5 is 5 amps).
Note: Fuses F2 - F5 are all slow blow fuses.
Do not jumper fuse or replace with any fuse
except as specified. Failure to comply could
result in severe personal injury, death, or
substantial property damage.
7. Install control module cover and top access cover after fuse
inspection.
8. Restore power to the water heater at the external disconnect
switch and verify water heater operation (Section 10 -
Start-up) after completing water heater service.
ƽ WARNING
ƽ WARNING
NOTICE
ƽ WARNING
Installation & Service Manual TM