AERCO KC1000 Heater w/Mod-Box Controller - Manual (Page 44)

TROUBLESHOOTING
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SECTION 7- TROUBLESHOOTING GUIDE
This troubleshooting section is intended to serve
as a guideline to determining and solving faults
on the unit. Whenever a fault occurs, proceed as
follows:
1. Determine the cause of the fault by following
the procedures within this section.
2. Once the cause has been determined, take
the proper actions to remedy the fault.
3. Start the unit in accordance with this manual.
In the event that a fault cannot be remedied,
contact your local AERCO Representative or the
factory for Technical Assistance.
WARNING!
ELECTRIC SHOCK HAZARDS EXIST
THAT CAN CAUSE SEVERE INJURY.
DISCONNECT POWER BEFORE
PERFORMING ANY MAINTENANCE
AND/OR SERVICING.
WARNING!
NEVER JUMPER (BY-PASS) ANY SAFETY
DEVICE. DAMAGE, OR PERSONAL
INJURY COULD RESULT. USE AN OHM
METER FOR CHECKING CONTINUITY
ON SAFETY DEVICES.
WARNING!
TROUBLESHOOTING PROCEDURES, AS
OUTLINED IN THIS SECTION, MUST BE
PERFORMED BY QUALIFIED SERVICE
PERSONNEL.
7.1 LOW GAS PRESSURE
The LOW GAS PRESSURE message indicates
that gas pressure has gone below 7” W.C.,
tripping the low gas pressure switch.
7.1.1 LOW SUPPLY GAS PRESSURE
7.1.2 GAS PRESSURE SWITCHES
Recommended Troubleshooting Equipment:
16” Manometer
Analog or Digital Ohmmeter
7.1.1 LOW SUPPLY GAS PRESSURE
1. Install a manometer in the unit manifold as
per Section 4.2.1
2. Check the static pressure to the unit. It
should be 10” to 12” W.C .
3. If the static pressure to the unit is lower than
10” W.C., readjust the supply regulator until
it’s output is 10” to 12” W.C. If a static supply
pressure of 10” to 12” W.C. cannot be
obtained, proceed to Step 8.
4. If static pressure is already 10” to 12” W.C.
or you have readjusted the static supply
pressure, start the unit.
5. If gas pressure drops to below 7” W.C.
during the Ignition cycle, proceed to Step 8.
6. If gas pressure does not drop below 7” W.C.
in any one of the above steps slowly
increase the input percentage in steps of
10% while monitoring gas pressure.
7. If gas pressure drops below 7“ W.C. tripping
the gas pressure switch, proceed to step 8.
8. If gas pressure stays within the unit’s
specifications of 8.5” at maximum firing rate
and has a maximum static pressure of 14”
proceed to Section 7.1.2.
9. Check the gas pressure to the unit’s supply
regulator. It should be 14” W.C. or greater. If
the supply pressure is 14” W.C. or greater,
check the supply regulator and supply piping
for correct sizing.
7.1.2 GAS PRESSURE SWITCHES
1. If static pressure to the unit is correct,
disconnect electric power to the unit.
Remove wires #20 & #32 from the low gas
pressure switch.
2. Using an ohmmeter, check the gas pressure
switch for continuity. Be sure that the gas
supply to the unit is on.
3. Replace the switch if it does not show
continuity.
4. If the switch shows continuity, reconnect
wires #20 and #32 to the switch. Remove
the 15-pin connector from the control panel.