Troubleshooting - Procom WZN18HLA Manual

WARNING: If you smell gas:
• Shut off gas supply.
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your
building.
• Immediately call your gas supplier from a neighbor's phone. Fol-
low the gas supplier's instructions.
• If you cannot reach your gas supplier, call the fire department.
WARNING: Only a qualified service technician should service and
repair heater. Make sure that power is turned off before proceeding.
Turn off and let cool before servicing.
CAUTION: Never use a wire, needle, or similar object to clean
ODS/pilot. This can damage ODS/ pilot unit.
IMPORTANT: Operating heater where impurities in air exist may create odors. Cleaning sup-
plies, paint, paint remover, cigarette smoke, cements and glues, new carpet or textiles, etc.,
create fumes. These fumes may mix with combustion air and create odors.
Note: All troubleshooting items are listed in order of operation.
The millivolt system and individual compo-
nents may be checked with a millivolt meter
having a 0-1000 mV range. Conduct each
check shown in chart below by connecting
meter test leads to terminals as indicated.
Check Test
To Test
Connect Meter
Leads to
Terminals
Thermostat
Contacts
Meter Reading
Should Be
200068-01A

TROUBLESHOOTING

CHECKING SYSTEM OPERATION
A B
Complete Thermopile
System Output
2 & 3 1 & 2
Closed Open
Closed Open
www.usaprocom.com
A. Complete Millivolt System Check
("A" Reading - Thermostat contacts
CLOSED - Control Knob "ON" - Main
burner should come ON)
a. If the reading is more than 100 millivolts
and the automatic valve still does not
come on, replace the control.
b. If the closed circuit reading ("A" reading) is
less than 100 millivolts, determine cause
for low reading, proceed to Section B
below.
B. Thermopile Output Reading
Check
("B" Reading - Thermostat contacts OPEN-
Main burner OFF)
1. Check gas pressure to the unit. If gas
pressure is within minimum and maximum
on data plate, then check pilot voltage,
325 millivolts minimum. If the minimum
millivolt reading is not obtainable, replace
pilot.
25