Reznor, RHC21 8000 Installation EN May 2021 D301319 Issue 0 Page No 45 of 52
10. User operating instructions
10.1 Checks before lighting the air heater
Before lighting the heater, ensure:-
1. The electrical supply to the heater is OFF
2. All air outlets associated with the ductwork
system served by the heater are open
3. The control thermostat is set to MAXIMUM
4. Any time control associated with the system
is set to an ON period
5. Any other controls associated with the
system are calling for heat
10.2 Lighting the air heater
1. Switch on the electrical supply at the heater
2. Provided the associated external controls are
calling for heat (and in an ON time period if
time control is provided), the heater start up
sequence will automatically commence.
3. After a short delay, the heater will light and
the green BURNER ON indicator will light.
4. If ignition is unsuccessful there will be a
purge period followed by ignition. Three
ignition attempts will be made before the
heater goes into lockout mode.
5. Once in lockout mode, the LOCKOUT
indicator will light. A lockout is reset via the
switch next to the lockout indication light.
Contact the installer or supplier
if the heater will not light after
several attempts.
10.3 To shut down the air heater
1. For short periods, turn the associated
thermostat to OFF or its lowest setting.
2. For long periods, again turn the associated
thermostat to OFF or its lowest setting. Wait
5 minutes then turn OFF the electrical supply
at the associated local isolator.
10.4 Overview of operation
The heater MUST NOT be controlled
by switching the main electrical
supply to it ON and OFF
The ignition sequence will commence each
time the external controls (e.g. Time clock,
room thermostat etc.) call for heat / operation.
The internal combustion fan will run to purge
the heat exchanger and flue, then an ignition
attempt will be made. The ignition spark will be
generated, the main gas valve opens and the
burner will light. The green 'ON' indicator will
illuminate.
When the external controls are satisfied the
burner will be turned off and approximately
2 - 3 minutes later the combustion fan will be
automatically stopped. If the burners fail to light
the control box will make a total of 3 attempts
at ignition.
In the event of overheating for any reason,
overheat controls operate to switch off the
burner. The limit control LC3 (which operates at
a higher temperature setting) switches off the
burner to a lockout condition. This will require
a thorough check of the heater and a manual
reset via the LC3 limit control body followed
by the lockout reset switch. A cooling time of
about 3 minutes is necessary before resetting.
The appliance is fitted with an LED status light.
This can be used to determine the current status
of the appliance and help to diagnose fault
conditions. See LED Status table in section 5.11
(page 27) for more information.
10.5 Maintenance
Maintenance and service must only be carried
out by appropriately qualified persons. It is
in your interest to ensure proper service and
maintenance is carried out at a regular basis.
Periods between service are dependent upon
the local environment where the heater is
installed. All gas appliances should be serviced
at least annually, preferably at the end of the
heating season.
