Rinnai REU-2007W, Руководство по обслуживанию

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1* <
The burner assembly is made up of 18 identical
stainless steel bunsen burners, secured by an
aluminised steel framework. An aluminium manifold
with 18 integral injectors supplies gas to the burners,
and is attached to the front lower cover of the burner
box. Changeover Solenoid Valve
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The changeover solenoid increases the flexibility of the regulator/modulating valve by supplying gas
to the right hand side of the burner only, [up to 40% input] or both sides of the burner, [40% input]
+ [40 - 100%] through the tandem manifold.
3* (
Air for combustion is supplied by a centrifugal fan
driven by a DC motor. After a pre-purge period of
0.2 seconds, the fan speed is controlled by the PCB
to provide the correct volume of air for combustion.
The calculation for the fan speed is based upon
incoming water temperature, water flow and the
temperature selected on the remote controls.
The actual speed of the motor is continuously
monitored by a magnetic pulse sensor.
This sensor emits 4 pulses per rotation of the fan. This is the fan feedback or confirmation data
processed by the PCB and used for 2 operations.
1. The fan speed is constantly correctly to provide optimum combustion conditions.
2. To determine the opening degree of the modulating gas valve, so that the gas rate always
matches the volume of air for combustion, as well as the input required to heat the water.
The reason for controlling the opening degree of the modulating gas valve based upon data from the
combustion fan is that the gas valve is able to react much more quickly to a change in control signal
than the combustion fan. Controlling the gas valve based upon data from the combustion fan means
that combustion remains satisfactory, even if there are sudden changes in input conditions.
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Water flow is detected by a turbine/magnetic pulse generating device. Water flows through the
turbine/magnetic sensor providing information to the PCB by generating a pre-determined number
of pulses in proportion to the water flow. These pulses are counted by the PCB - no pulse indicates
no water flow. The frequency of the magnetic pulses increases as the water flow increases, this
enables the PCB to calculate the exact water flow, and determine the water flow in litres/minute. As
soon as the required water flow is detected, the PCB activates the combustion fan. The combustion
fan speed is monitored by a magnetic pulse sensor. The output from this sensor is processed by the
PCB which opens the gas modulating valve to a degree proportional to the fan speed. See above for
further details on the combustion fan.
The water flow control consists of a plug and barrel valve which is rotated by a motor to increase or
decrease the volume of water passing through the heat exchanger.