3
Alpha SolarSmart 90 - User Instructions
The solar energy supplied by a system varies with the orientation and tilt of the collector, which will usually be determined by the
existing roof. However, the predicted variation is slight. For a collector facing anywhere between SE and SW and tilted from the
horizontal between 5° and 60°, the annual solar energy supplied will be at least 90% of that obtained at the optimum collector
position.
It should be remembered that shading from trees, buildings etc., can produce a significant decrease in system performance, and
collectors should be positioned to minimise shading from the sun in the middle of the day.
3 POSITIONING OF THE COLLECTOR
Fig. 2 - Alpha combination boiler controls
The domestic hot water thermostat must always be set to the maximum setting. A label has been supplied which should have
been positioned over the domestic hot water thermostat knob, as shown below, to ensure the maximum setting is maintained.
4 SYSTEM OPERATION
WORKING PRINCIPAL - Fig. 3
The solar collector uses the energy of the natural light to heat the water being circulated around the collector. When the heated water
enters the drain back unit, heat is transfered into the stored water via a heat exchanger coil. Stored domestic hot water is pumped from
the bottom of the solar cylinder through the drain back unit heat exchanger coil where it is heated and returned to the cylinder.
When a hot water tap is turned on mains water flows into the bottom of the solar cylinder and hot water flows out of the top towards
the solar valve at the boiler. If the water from the cylinder is above 60°C the solar valve diverts the flow directly to the tap, if the flow
is less than 60°C the valve diverts the flow through the combination boiler. When the flow is via the combination boiler the water
temperature is maintained by the boiler. As the temperature of the water entering the boiler is higher than the normal incoming
mains water, less gas is required to heat it to the required temperature thereby saving energy costs.
IMPORTANT
This Combi boiler is fitted to an
Alpha Solar system and the hot
water thermostat MUST always be
set at maximum (No.9).
Cylinder pump
Mains cold water inlet
Warm water to boiler
Hot water to taps
Solar valve
Solar cylinder
Upper cylinder
temperature sensor
Lower cylinder
temperature sensor
Collector sensor
Solar collector
Drain back unit
Heat exchanger
Drain back unit
pump
Fig. 3
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