M C Series – Warm air heaters – Installation, Operation and Maintenance Manual
40
Ed.
04/2007
F) Failure in the flame control unit or in its electrical connections.
G) Failure in the gas valve or in its electrical connections.
H) Soft opening pressure too low.
I) Check that the unit has a good earth.
J) Air is inside the gas pipes.
CASE NO. 2: THE UNIT LOCKS OUT DURING
OPERATION.
K) The gas supply is suddenly cut off due to a failure in the gas system. The ignition
control repeats the ignition cycle, after which the gas valve closes locking out the unit
(accidental gas inlet cut off).
L) The power supply is suddenly cut off due to a failure in the electrical supply mains. If
the electrical cut off period is prolonged, the temperature limit thermostat (M1) locks
out the unit, thus preventing re-ignition. When electricity returns, push the reset button
which is placed on the thermostat, inside the unit control panel, below the black screw
plug (accidental power supply break).
M) The flame sensor touches the unit ground or it is disconnected.
N) The gas valve does not open due to a failure of the valve itself or of its electrical
connections.
CASE NO. 3: THE TEMPERATURE LIMIT THERMOSTAT (M1) STOPS THE
BURNER.
O) The heat exchangers have overheated. Check the operation of the fan, gas pressure
and nozzles.
P) The exchangers overheat due to accumulation of dirt. Clean the exchangers (dirt can
also obstruct ventilation and supply grille).
To reset the thermostat push the button placed on the thermostat inside the unit control
panel, under the black screw plug.
CASE NO. 4: THE BURNER GOES OUT AND DOES NOT RE-IGNITE EVEN IF ROOM
TEMPERATURE REQUIRES IT.
Q) Check the performance of the room thermostat and its electrical connections.
R) Check the position of the room thermostat (check that it is not influenced by external
heat sources).
CASE NO. 5: THE EXHAUST FAN WILL NOT
START.
S) Check that the room thermostat is set on the desired temperature.
T) Check the electrical connections of the exhaust fan and its capacitor.
U) Check integrity of the unit’s protection fuse.
V) Make sure that neither the limit nor the safety thermostat have operated.
