Technical data

Any ancillary electrical items e.g. room
thermostats , time switches, remote panels
etc, must be wired into the heater electrical
circuit in accordance with the diagrams
provided
Note
When external controls operate to switch
the heater OFF, power to the heater should
remain to allow the fan to continue to operate
to sufficiently cool the heater thereby
preventing damage to the heat exchanger.
Fan limit control
( Situated inside the right hand side panel)
FAN ON 50
c
FAN OFF 30
c
These settings may require slight adjustment
on commissioning
Fan control (white button)
The fan control switch features normally
open 230V contacts, and is wired to control
the live supply to the fan motor . When the
circuit is made, the fan will switch on when
the heat anticipator has closed the fan switch
contacts. When the thermostat or time switch
shuts down the burner, the fan will continue
to run until the thermal switch has cooled
sufficiently to prevent the residual heat from
damaging the heater or its controls.
On start up the fan delay prevents air being
circulated until the desired temperature is
achieved
Limit control (red button) SET at 100
c
An adjustable high temperature manual reset
limit control. If this control needs resetting the
cause should be determined and rectified
immediately.
On models with two fans a second limit
control is situated inside the right side panel
and is wired in series. Operation of either
switch will shut down the heater. On larger
models there will be additional limit stats
fitted
Caution
The power supply to the fan must not be
interrupted, the only time when power supply
can be disconnected or interrupted is during
servicing or in emergencies
If there is a requirement for the heater to be
switched off over night then the gas valve
circuit should be opened via a time switch,
etc, as per the wiring instructions and
diagrams supplied within section 6.0 of this
manual.
2.7 Gas installation
Warning
Please read notice on page 3 of this
manual
As there have been recorded instances of
the deposition of copper sulphide dust within
the valves and orifices of gas appliances as
a direct result of a reaction between the
hydrogen sulphide contained in some natural
gasses and copper pipe we recommend that
the heater(s) should not be connected to any
natural gas pipe distribution system which
utilizes copper pipework, including final
connections. Instead steel pipework should
be used throughout.
In the event that it is impractical to use steel
pipework or where installers are obliged or
insist on using elements of copper pipework
within the installation then we strongly
recommend that the gas supplier be
consulted as specific conditions and
requirements may be necessary.
The Variante range of heaters are all
manufactured and pre set for use with
Natural Gas, and all feature 1/2” or 3/4” BSP
connection points. Prior to installation the
supply characteristics (gas type and
pressure) must be checked to ensure that
they are in accordance with the data plate on
the heater.
The gas supplier should check that the meter
and service connection to the heater are
capable of delivering the required volume of
gas, thereby ensuring that the minimum
burner pressure can be achieved.
Consideration should be given to the
pressure drop on single and multi heater
installations and the effect they may have on
other plant sharing the supply.
If it is necessary to fit a gas pressure
booster, the controls must include a low
pressure cut off switch which must be fitted
on the supply / inlet side of the booster. It is
also a requirement that the gas supplier is
advised prior to the installation or fitting of
the booster.
Each heater supply must be fitted with a
separate isolating cock positioned adjacent
to and upstream of the union which must be
sited outside the heater.
The isolating cock should be of the 90
0
turn