5
Space Heating". The installation must also be in accordance with the relevant requirements of “The Gas Safety
(Installation and Use Regulations) and “Amendment regulations 1990” and “Electrical Regulations” (in GB the IEE
Regulations). The requirements of the “Local Building Standards Office”, the premise “Insurance” undertaking and
the “Fire Office” must also be observed.
The modulating pre-mix burner has a modulating range from 100% to 30% full fire rate. The gas valve delivers the
fuel in proportion to the combustion air flow rate in line with the default factory settings. The concentration of carbon
dioxide (CO2), unlike atmospheric burners, is more or less constant throughout the firing range. This will result in a
higher thermal efficiency as the heat output decreases. Perfect mixing of the gas with combustion air combined with
a semi-radiant flame, contributes to a combustion with very low emissions of carbon monoxide (CO) and nitrogen
oxides (NOx).
In the event of reduced combustion air (e.g. obstructions and/or flue or combustion air runs that are too long), the
solenoid valve automatically reduces the gas, keeping the combustion parameters at optimal levels. In the case of
poor combustion air, the solenoid valve closes and no more gas is supplied.
When the external control calls for heat, an electronic control begins the ignition sequence to provide for a safe
start. Under normal conditions the supply air fan motor (by others) runs constantly and after a call for heat it
switches the heater on through a room or duct stat. However, in some applications, about 30 seconds after the call
for heat, the fan control relay will activate the fan motor of the air handler. The normal operation of RHCLN will then
operate as follows: upon call for heat the pre-mix gas burner fan (1) introduces the optimal combustion air/gas
mixture - dependent upon the modulating valve firing rate (2). Additional combustion air/gas mixing can occur
inside the fan of the pre-mix burner (1), prior to being fed into the burner firing tube. On the external surface of the
burner tube, a radial flame develops once the gas/air mixture is ignited. Combustion products, prior to being
exhausted via the flue, heat up the combustion chamber (3), the rear flue manifold (4), the heat exchanger tubes
(5) and the heat exchanger manifold (6). The electronic control within the RHCLN will supervise the flame during
the entire heating cycle to ensure safe operation. When the required room temperature is reached, the main burner
will shut down leaving the fan (supply air/AHU) running to cool down the heat exchanger
The temperature of the combustion products, whilst passing through the heat exchanger (5) falls below dew point,
and retrieves the latent energy contained in the water vapour normally generated during the combustion process.
The condensate produced is collected in the heat exchanger manifold (6) and in turn leaves the appliance via the
condensate connection to an external drain system (by others).
1.2 Warranty
Warranty is void if:
RHCLN heaters are installed in atmospheres containing flammable vapours or atmospheres containing
chlorinated or halogenated hydrocarbons or atmospheres containing any silicone, aluminium oxide, etc.,
that adheres to spark ignition flame sensing probes.
The installation is not in accordance with these instructions.
The maximum air flow through the heat module exceeds that stated in this document.
The required minimum air delivery is not respected.
The inlet temperature exceed/are lower than the working parameters shown in the technical data table.
