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4.7 GENERAL OPERATION
1. Remove all foreign objects from blower casing and ensure that all access panels are installed and secured.
2.
Connect manometers to confirm the main burner and supply pressures.
3. De-isolate gas and electrical supply to the heater.
4. Set wall switch to “Heat and low fan”.
WARNING!
Blower will begin to rotate. Ensure doors are correctly installed
and no tools are present within the blower box section of the unit.
5. With power and gas to the unit and switched to heat and fan the pilot will attempt to ignite. The spark igniter should
be heard briefly until the pilot is established. When pilot ignites, check that the flame is licking over the edge of the
main burner adjacent. If not the pilot flame may be adjusted by the small adjusting screw located on the top of gas
valve marked pilot adj. Note it may take several attempts for the pilot to light especially on LPG unit due to the long
pilot gas line and small orifice size. Cold weather commissioning may also increase the pilot light time. If the pilot
does not ignite refer to section 6.3 for possible causes.
6.
The flame rod will sense the pilot and open the main gas valve. The main burners will ignite. Ensure that all burners
are lit. Operate the unit continuously for a minimum of 45min to confirm correct operation.
7.
Check operating pilot and manifold pressures against the specified pressures and adjust accordingly. Record
results. Refer to Section 3.4.7 Setting Gas Valve Pressure. If correct pressure at the burner cannot be obtained by
adjusting the main gas regulator in the unit, check pressure at inlet of unit stop cock. If inlet pressure is less than
minimum specified on the label, either gas supply line to the unit is under sized and/or restricted or the meter outlet
pressure is too low.
WARNING:
If the gas pressure is lower than specified it may result in burner light back, potentially causing damage
to the burners and increased soot buildup in the heat exchanger and flue.
Contact the local gas authority – DO NOT
attempt to adjust main gas regulator where gas enters premises or at
meter unless authorized to do so.
8. When the unit is turned to “HEAT” the temperature rise across the heat exchanger must be within the range of 11°C
to 33°C on full flame. The RLU will display the leaving air temperature. The rise in temperature can be controlled
by changing the airflow with the dampers by altering the position of the dampers. If the temperature rise is not
specified it shall be set to 22°C. Once the required temperature rise is achieved the dampers are be locked into
position.
9. Perform modulating motor check as per Section 4.4.4. As the room temperature approaches the set temperature
the modulating motor should modulate down to low gas fire. Once the modulating motor reaches the lower set limit
the main manifold pressure should be the low-pressure value specified in Table 11.
10.
Once the room temperature reaches the set limit and modulation has occurred the unit will shut off the gas to the
main burner or the modulating motor will perform fine adjustments to maintain a consistent temperature.
11.
When the unit is operational cut power to the unit externally at an isolator and note that the flame goes out and that
the gas valve shuts. After 1 minute restore power to the unit and confirm that the unit restarts and begins normal
operation.
COMMISSIONING INFORMATION
