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UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
22
SECTION 11: USER INSTRUCTIONS
11.1 User Instructions
The UHA[S] Series heaters are fully automatic and
operate from the external controls fitted on site.
11.2 Heater Operation
When the heater has been switched on by the
thermostat installed on site, the main burner will
automatically turn on.
The burner control box will control the safe ignition
of the flame.
All heaters require a constant gas and electricity
supply which must not be interrupted during the
normal operation of this heater.
11.3 Lighting Instructions
11.3.1 To Turn On Heater
1. Ensure that the electrical and gas supplies to
the heater are on. Check that the on site
controls are "ON".
NOTE: The thermostat setting must be above the
ambient temperature for the heater to operate.
2. The automatic firing sequence will begin as
described on Page 20, Figure 10. The heater
will now operate automatically under the control
of the on site controls.
11.3.2 To Turn the Heater Off
Set the thermostat to the "OFF" position.
The burner will turn off immediately.
The fan will continue to run for 90 seconds.
To restart, turn the thermostat above room
temperature.
11.4 Simple Troubleshooting
Some possible reasons for the heater not operating
are:
1. Gas supply not "ON".
2. Electricity supply not "ON".
3. The time and/or temperature controls are not
"ON".
4. A limit switch may have operated. This may be
caused by an interruption of the electrical
supply, failure of the distribution fan or vent or
heat exchanger blockage.
If a temperature limit switch persistently trips, there
is a fault which must be investigated by a contractor
qualified in the installation and service of gas-fired
heating equipment.
11.4.1 Simple Troubleshooting (Burner Fault)
If the burner fails to ignite for any reason, it will retry
for ignition (4 trials total). After 4 unsuccessful
ignition trials, the control will put the heater into
lockout for 1 hour.
Lockout should not occur during normal operation of
the heater and indicates there is a fault condition
which must be corrected. There is an LED light on
the ignition control that flashes codes to assist in
fault correction. See Figure 12 for LED indication
codes.
Figure 12: LED Diagnostic Codes
WARNING
Electrical Shock Hazard
Disconnect electrical power before servicing.
Failure to follow these instructions can result in
death or electrical shock.
LED INDICATION FAULT MODE
Slow Flash Normal Operation - No call for heat.
Fast Flash Normal Operation - Call for heat.
2 Flashes Ignition Lockout - No flame detected.
3 Flashes Airflow Fault - Pressure switch open or closed.
4 Flashes Temperature Limit or
Manual Reset Limit Switch Open
5 Flashes Flame Sense Error - Gas valve not energized.
Steady On Internal Control Failure