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VP
x Range Users, Installation & Servicing Instructions Doc Ref M205 issue 1.2 Nov 2018.
Important: The heater must NOT be
controlled by switching ON and OFF the
main electrical supply to it.
1) Standard Units
The ignition sequence commences each time the external
controls e.g. time clock, room thermostat, controller etc.
call for heat. The internal exhaust fan will run and, when
sufficient combustion airflow is proved by the air pressure
switch, the ignition spark will be generated, the main
gas valve opens and the burners will light on HIGH FIRE
for the first 30 seconds irrespective of the requirements
of the external control. The green ‘ON’ indicator will be
illuminated. The heater fan will automatically start 30
seconds after the burners light. After the first 30 seconds,
the heat output will then be controlled either to high fire
or low fire depending on the requirements of the space
being heated and the external controls fitted. When the
external controls are satisfied the burners will be turned
off and 2½ minutes later the heater fan will automatically
stop. If the burners fail to light the control box will make
another four attempts at ignition before going into burner
lockout. The amber ‘Lockout’ indicator/reset switch will be
illuminated.
2) Modulating Units
When the burners are alight, the heat output will be
controlled to any point between high and low fire;
depending on the requirements of the space being heated
and the external controls fitted.
3) Summer / Winter Modes
Certain types of external controls will provide for two
modes of operation i.e:
Summer: The heater fan alone will run at the dictate of
the external controls to provide air movement.
Winter: The heater will operate normally.
4) Overheat Thermostat
This operates if high temperatures within the heater are
detected, the burners are turned off and a Red indicator
lamp on the front panel is illuminated. VPx35 - 70 units
have a single thermostat located inside the heater.
VPx90 - 140 units have an additional thermostat on the
side of the unit at the opposite end to the controls (either
thermostat can go to limit and shut off the burners). The
fault condition must be identified and rectified and the
thermostat manually reset via the red high limit reset
switch. When the unit has cooled, identify the limit stat,
remove the black cap and press the reset button. The red
indicator lamp will go out and the unit is operational again.
If the heater has not been left operational
proceed as follows.
The following preliminary checks should be made before
lighting the heater(s)
a) Ensure that the ELECTRICAL supply to the heater is
switched OFF.
b) Check that any warm air delivery outlets are open.
c) Check that the thermostat is set.
d) Check that the clock control is set to an ON period.
e) Check that any other controls are calling for heat.
1. Switch on the electrical supply at the isolator
2. If the Red Limit indicator lamp is illuminated, identify
the limit stat, remove the black cap and press the reset
button.
3. The startup sequence will commence. After a short
delay the burners will light and the green ‘ON’ indicator on
the front of the heater will be illuminated.
4. If the burners fail to light the control box will
automatically restart the ignition sequence. If after 5
attempts at ignition the burners have still failed to light
the control box will go to lockout and the Amber lockout
lamp on the front of the heater (or on the low level remote
reset, or MC200/MC300 if fitted) will be illuminated. To
restart the ignition sequence depress the reset button on
the low level reset for about 1-2 seconds.
WARNING: If it is not possible to light the
heater after several attempts, contact the
installer or local service company.
1) For Short Periods:
Turn the room thermostat to the OFF, or set to 'Summer
Mode'.
2) For Long Periods:
Complete step 1 above. Wait for 5 minutes and then turn
OFF the electrical supply at the isolator.
