Alpha Alpha Plus DH Units, Instructions For Installation Manual, Page: 6 / 14

3/
OPERATION
Domestic hot water is available continuously and always takes priority over central
heating. If a demand for hot water is required during a central heating period the
controls will automatically switch to the hot water mode until the demand is
satisfied. This interruption in the central heating is only when the demand for hot
water is present and should not be noticed by the User.
3.1
Domestic Hot Water mode
When a demand for hot water is sensed by the flow switch, the DHW valve is
opened via a relay and district heating water is circulated to the plate heat
exchanger thus heating the incoming mains water. The hot water is maintained at
the set temperature by the hot water thermostatic valve regulating the district
heating water flow to the heat exchanger. When the flow switch senses that hot
water is no longer required the DHW valve closes.
3.2
Direct Central Heating
If there is a call for heating from an external control the CH valve will open and
allow district heating water to circulate to the dwelling’s radiator circuit. When there
is no demand for heating the CH valve will close. If there is a demand for hot water
the CH valve will be closed and will not be allowed to open until the hot water
demand has been satisfied.
4/
INSTALLATION
4.1
Unpacking
(1) The contents of each box is as follows:-
DHW Box - Assembled unit panel mounted with heat exchanger,
flow switch, DHW valve, hot water controller, control box
and pipework
Thermostat and sensor
Thermostat sensor kit, screws and wall plugs
Two 22mm isolation valves, strainer, 15mm Isolation valve
DCH Box - CH valve, two 22mm isolation valves
(2) Unpack and remove loose items
6