6
DESCRIPTION OF EQUIPMENT
Heat exchanger
•
Stainless steel construction easily accessible for
inspection and cleaning and maintenance operations.
•
Patented exchange elements made in stainless steel
modular sections with large surface area, trapezoidal in
section with swirl impressions for which give thermal
yields of over 90%. The exchange elements have no
welded joints or seams near to the burner flame so as
to avoid exposure of any weak points.
Flue outlet
with integral flue venter to assist dispersal of
combustion gasses.
External casing
Encloses all controls giving a good aesthetic appearance
and streamlined look whilst allowing for easy inspection.
The casing consists of removable panels and also
includes:
A burner compartment which is totally sealed off, with an
inspection door;
Radiant heat insulation on the surfaces closest to the heat
exchanger;
Outlet grille for directing the warm air.
Fan assembly
One or two centrifugal fans operated by a single electric
motor via pulleys and belts the motor pulley is adjustable to
give effective cooling of the combustion / heat exchanger.
The position of the fan(s) produce greater effective cooling
of the combustion chamber, optimising the heat exchange
and avoiding overheating.
An up rated fan is also available.
Control and protection equipment
This is electronic with ionisation flame detection and
ignition controls.
The equipment controls and monitors the operation of the
burner in the following sequence.
Checks the differential pressure switch operated by the
flue venter is in the closed position and the flue venter is
working;
Checks the air temperature of the combustion chamber
(below 100ºC)
Opens the gas solenoid valve;
Starts burner ignition;
Detects flame signal from flame probe and allows normal
heater operation.
Failure in any of the above sequence will result in the
control box shutting the gas valve and stopping the heater.
The Heater will go to lockout and can be only be reset
manually by pressing the red light on the front of the
equipment.
Gas solenoid valve
The multifunctional 1 stage gas valve
(Single Stage)
and 2 Stage gas valve
(Two Stage )
consists of:
•
Safety solenoid valve
•
A regulatory solenoid valve
•
A pressure regulator
•
A gas filter
Atmospheric multigas burner assembly
Consisting of:
•
Galvanised steel manifold
•
Visual monitoring aperture for the electrodes and flame
observation
•
3 or 6 stainless steel burner bars
•
Ignition and Detection electrodes
Note:
the type 4-5-6 are equipped with two gas manifolds,
each manifold has an ignition electrode.
Control and safety thermostat
The heater is controlled by three thermostats pre set to the
following.
LM Limit thermostat (100°C)
Capillary type. Manual Reset
Act as a safety device and shuts down the burner if the
heater goes to overheat. The yellow light will flash when in
overheat. The LIMIT thermostat is reset by the removal of
the plastic cap situated on the control panel inside the
heater, and manually pressing the reset button, after first
ensuring that the fault has been rectified. (calibrated
at100°C). Replace cap after resetting thermostat.
TR Regulatory thermostat (0 – 90°C)
Capillary type. Automatic reset.
The thermostat monitors the temperature of the airflow and
will shut down the burner if the set level is exceeded
(calibrated at 70°C). Once the fan has sufficiently cooled
the heat exchanger, the burner will automatically relight.
The yellow indication light will flash untill the burner
relights. If this fault persists the cause should be
investigated.
SND Control probe (0 – 40°C)
Connected in series with the thermostat TR. The probe will
start the fan when the temperature reaches 30°C
(approximately 30 seconds from burner ignition). When the
desired room temperature is reached and the burner shuts
down, the probe will allow the fan to run for approximately
3- minutes until the heat exchanger has cooled
sufficiently.
The probe also monitors the operation of the TR
thermostat and if a fault is detected will change the yellow
flashing light to a continous on light. In addition to this the
SND probe monitors the temperature of the return air and
will switch off the fan prior to the 3-4 minute run on time if
the heat exchanger has cooled sufficiently (this avoiding
cold air flow from the heater).
Differential air pressure switch
This switch will shut the gas valve if the flue venter fails or
there is an obstruction in the flue, or in the air inlet
preventing the flue venter from operating.
Flue venter
This consists of a centrifugal fan which
Is run by an electric motor with self-cooling rotor the
cooling air is supplied through a duct pipe situated in the
axial fan air flow.
Indication lights
These consist of three different coloured lights on the front
of the heater:
•
Green light –
indicates normal working. Illuminates
when the gas solenoid valve opens
•
Yellow light –
indicates the operation of the LM, TR
and SND thermostat.
•
Red light -
to indicate lockout of the heater by the
control circuit failure.
•
Reset button
to reset the lockout
Flue spigot
A flue spigot (100mm) is situated at the rear of the heater
for connection of flue pipes.
Combustion air spigot
A combustion air spigot (100/150mm) with a safety mesh
of less than 16 mm Ø on the rear of the heater allow for
connection of combustion air pipe.
