Nu-Way MDFL 2800 - 38, Installation & Maintenance Manual

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INTRODUCTION
This manual has been produced to enable users to install, commission and use the MDFL burners
safely and efficiently. At each stage the conditions that should be met, the adjustments and other
actions that should be carried out are detailed. The locations of the various components and
adjustment mechanisms are identified. Where appropriate, this information is supported by tables
and graphs.
FEATURES
Developed through extensive field experience in the UK and overseas markets, the MDFL series of
dual fuel burners meets all current test authority requirements in these markets and sets new
standards in efficient and reliable operation.
MDFL burners are designed for flange mounting to the appliance frontplate and they are delivered
ready to install.
Burner Capacity Burner Model Capacity kW
The figures quoted are nominal burner MDFL 2800-38 774 - 2730
outputs based on the nett calorific value. MDFL 2800-41 774 - 2730
Please refer to the Appendix of this handbook for detailed burner performance data.
Fuel
MDFL burners are suitable for light distillate oil (Class D) and Natural Gas
Air Fan Size
To match MDFL burners with the appliance, with
respect to both burner output and appliance
resistance, a number of combustion air fan sizes
are available for each model, as detailed in the
table opposite.
The fan size quoted is the diameter of the fan impellor (measured in cm) and appears as a suffix to
the model number. For example, a burner designated MDFL 2800-38 is a model 2800 with a 38cm
diameter combustion air fan impellor.
Controls and Safety Systems
MDFL burners are fitted with a combustion airflow control and an air/fuel ratio control system which
together ensure smooth starting and optimum operating efficiency.
An air pressure switch provides safe burner shutdown if the combustion air supply becomes
insufficient for complete combustion. The burners additional safety systems include for gas pressure
monitoring (low and high) whilst gas firing. Continuous flame supervision is provided by an ultraviolet
(UV) cell and automatic programming control unit.
Operating Mode
The MDFL 2800 burners operate in fully modulating mode when firing on gas, and 2 stage (high/low)
mode when firing on oil (Fully modulating mode is an optional extra for the MDFL 2800-38).
Oil Firing – 2 stage Operation
MDFL 2800-41 burner is supplied with a system designated ‘Sliding High/Low’ which uses a single
spillback oil nozzle (similar to that employed in the fully modulating mode) which is constrained to
operate at either of two fixed oil flows corresponding to the high and low fire rates. If the burner has
been correctly matched to the appliance, a turndown ratio of up to 3.0:1 may be achieved. The
MDFL 2800-38 is supplied with twin simplex oil nozzles, one for low and both for high fire.
Gas Firing – Both Models
When gas firing, the fuel gas flow is controlled by an automatic valve which, following commissioning,
precisely matches the fuel flow to the air flow to achieve the required fuel/air ratio at any point in the
full turndown range. If the burner has been correctly matched to the appliance, a turndown ratio
between 2.0 and 2.5:1 may be achieved.
MDFL 2800-38 & 2800-41 Issue 1 08/08
Page 7
Burner Model Available Fan Sizes
MDFL 2800 38, 41