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UNIT HEATER
Wherever possible a reading of the gas rate timed through the gas meter should be taken and compared
with the nominal rating in the Data Table, Section 2. The burner pressure should be adjusted to give
this nominal gas rate.
4.5.2 Commissioning the Gas Valves - L.P.G.
In all cases the gas valves for L.P.G. have the regulator put out of action. The heater is therefore set on
the inlet pressure to the gas valve which must be maintained at 37mbar for G31, (Propane) or
29 mbar for G30 (Butane).
No further adjustments are necessary
4.6 Commissioning Tests - All Heater Types
With the main burner operating for at least 15 minutes carry out a spillage test on the draught diverter
in accordance with BS 5440 Part 1 ensuring that all doors and windows in the area are closed and that
any extract fans are turned ON.
One method is to hold a lighted taper or smoke match just inside of the draught diverter and observe
that the smoke or flame is not drawn away from the heater.
Should it be indicated that the products of combustion are continuously entering the building from the
draught diverter then corrective action MUST be taken before leaving the heater to operate normally.
4.7 Combustion Testing - All Heater Types
Although there is no adjustment available to alter the combustion performance of the heater, other than
burner pressure, it is advisable to take combustion readings to determine the proper operation of the
heater.
To do this the flue gas is sampled at the test point on the flue, within 1 metre of the heater and tested for
contents of CO
2
(carbon dioxide), CO (carbon monoxide) and temperature rise. The values of CO
2
should be between 5.5% and 6.5% . CO should be no more than 0.0015% ( 15 PPM) and the temperature
rise of the flue gasses above ambient should be approximately 160°C to 180°C.
Combustion testing must be carried out with all covers etc. fully fitted as designed.
4.8 Pilot Drop-Out Test - Manual Ignition Models
Carry out the Pilot Drop-Out Test as described in Section 6.4 and ensure a positive result.
4.9 Turning Off the Heater - All Heater Types
To turn off the heater operate the external controls to the off position and the main burner will stop.
Allow the fans to run on until they are stopped automatically by the fan thermostat. The heater will
then be at rest until the controls call for heat once more. For long term closing down for summer etc.
then when the fans have stopped automatically, turn off the gas and electrical supplies at the isolators.
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