Section 14: Operation; Heater Lockout Indication (Optional); Testing; Commissioning (Multiburner) - Roberts Gorden Blackheat BH15UT Installation, Operation & Service Manual

®
B I
LACKHEAT NSTALLATION

SECTION 14: OPERATION

Figure 33: Sequence of Operation Chart

KEY TO
SYMBOLS
Thermostat
Fan
Pressure
P
Switch
Neon
Ignition
Gas
Valve
Flame
Sensing
Lockout Alarm
(optional)

14.1 Heater Lockout Indication (Optional)

In case of flame loss during operation of the heater, a volt
free contact relay is closed which enables the ROBERTS
®
GORDON Controller, BMS systems, etc. to receive a
signal and indicate precisely which heater has failed. If
your heater is equipped with "Heater Lockout" indication
(volt free), an additional wire has to be installed from the
heater's "volt free connector" to the monitoring computer.
See Page 48, Figure 33 for alarm sequence. NOTE: the
45 second pre purge signal must be suppressed.

14.2 Testing

Establish that a satisfactory purged gas supply and an
electrical supply is available to the heater. Ensure that all
time clocks and thermostats are set to call for heat.
With the gas supply cut off at the appliance isolating cock
and the electrical supply isolated by switching off at the
local switch and removing the appliance inlet plug, open
the control chamber secured by the centre screw. Loosen
the sealing screw from the pressure test point and
remove the cover cap from the governor.
Turn on the gas supply and connect appliance electrical
plug. Ensure that the timer or thermostat, if fitted, are set
to call for full gas rate. Switch on at the local switch. The
sequence as described should take place. If not, refer to
detailed fault finding sequence. When flame is
established, check the gas pressure reading and adjust if
necessary. Refer to burner data label.
Check the gas pressure at the outlet of the gas valve. See
Page 61, Section 18.9.1 or See Page 62, Section 18.9.2
for pressure settings or refer to the data plate.
Switch off the electrical supply (shutting down the heater),
remove pressure gauge - tighten pressure test point
screw, ensuring a tight gas seal. Replace governor cover
cap. Close burner side cover.
48
O S M
PERATION AND ERVICE ANUAL
T 0 T 1
P
Fan Neon
Burner Neon
20 sec
45 sec approx.
T 2 T 3 T 4
T P

14.3 Commissioning (Multiburner)

14.3.1 Establish that a satisfactory purged gas supply and
an electrical supply is available to the heater.
14.3.2 ENSURE that all the dampers are in the fully open
position.
14.3.3 With the gas supply off at each of the burners and
the electrical supply isolated, open the control chamber
secured by two self tapping screws.
14.3.4 Ensure that all time clocks and thermostats are set
to call for heat.
14.3.5 Switch on the electrical supply at the main isolator.
This will start the exhaust fan.
14.3.6 Balancing cold suction
Check each burner vacuum by connecting an inclined
pressure gauge to the tee on the pressure switch inlet
side in the burner. Adjust the damper so that the suction
is 1.9 mbar. Repeat for each burner.
14.3.7 Starting at the end burner (furthest from the
exhaust fan), with the inclined pressure gauge connected
as described above. Turn on the gas supply and connect
appliance electrical plug, reset the pressure switch by
removing suction from the inlet side of the pressure
switch waiting several seconds and reconnecting. The
start up sequence described on Page 48, Section 14
should take place. If not, refer to detailed fault finding
sequence. When flame is established, check the gas
pressure reading and adjust if necessary. See data label.
T 5 T 6
T P
20 sec
Interruption of main
flame sensing
T 7
T S
10 sec