Landa VLP3-1100 Operator's Manaul page 36

VNG/VLP SERIES PRESSURE WASHER
36
TROUBLESHOOTING — BURNER (Continued)
PROBLEM
HAVE PILOT FLAME,
MAIN BURNER WILL
NOT TURN ON
SHORT-CYCLING OF
MAIN BURNER. MAIN
BURNER TURNS
OFF BEFORE THE
BURNER SWITCH OR
FLOW SWITCH IS
TURNED OFF
POSSIBLE CAUSE
Faulty main valve coil in the gas
valve
Faulty ignitor/sensor and/or its
wiring
Ground wire not attached to
machine chassis
Faulty ignition control unit
Draft condition pulls flame away
from ignitor/sensor rod.
Faulty thermostat or water
temperature is too high
OPERATOR'S MANUAL
SOLUTION
Set test meter to 24 volt scale.
With pilot flame on ignitor/sensor, probe terminals
MV and MV/PV on the ignition control unit. If you
read 24 volts here, but not at the gas valve, there
is a loose wiring connection. Repair or replace a
as needed.
If you do read 24 volts at MV and MV/PV and the
pilot flame is impinging on the ignitor/sensor rod,the
problems may be:
a. Faulty ignitor/sensor and/or its wiring.
b. Faulty ignition control unit.
Set test meter to the ohm scale. Turn burner switch off.
Check continuity through the green ground wire and
its connections.
Reconnect the ignitor/sensor wire and the ground wire.
Turn burner switch on. With the pilot burning and the
flame on the ignitor/sensor rod, the main burner
should turn on. If it does not, replace the ignition
control unit.
Check the thermostat by bypassing at terminals
P1 & 1.
Set thermostat high. With main burner on, observe
the pilot flame impingement on the ignitor/sensor.
If pilot flame is small and draft condition pulls flame
from ignitor sensor rod, the burner will turn off and
then on again.
a. Adjust pilot flame higher or clean pilot oriface.
b. Bend ignitor/sensor rod closer to pilot flame.
If flame impingement on the ignitor/sensor is stable
and the system short-cycles, check the limit switch.
Set test meter to 110 volt scale
a. When the system cycles off, probe the switch
terminals of the limit switch.
b. If you read 24V accross the switch terminals the
limit switch is open. Replace the limit switch.
A pilot flame set too high will also cause burner to
short cycle. Pilot flame lifts over ignitor/sensor.