Ravenheat CSI85A, Installation And Servicing Instructions

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2.4 Domestic hot water mode
2.4.1 The heat exchanger in the D.H.W. circuit
is built into the main heat exchanger, and
domestic water is heated by converting
the water in the central heating circuit The
transference of heat is very high because the
two fl uids move in a counter direction fl ow to
each other.
2.4.2 Switch 33 in the (winter) position.
When a hot water tap is turned on a diaphragm
diverter valve excludes the central heating
circuit, the boiler automatically modulates to
maintain the domestic hot water at a constant
temperature.
Water temperature can be regulated using
the D.H.W. thermostat located on the front
control panel.
2.4.3 When domestic hot water is being drawn the
main burner and pump perform as they do
during central heating except that the burner
is commanded by the D.H.W. thermostat.
2.4.4 When D.H.W. is no longer called for the boiler
automatically returns to the central heating
mode.
2.4.5 Switch 33 in the (summer) position The
boiler functions like an automatic gas hot water
heater When D.H.W. is no longer required the
main burner fan and pump immediately turn
off.
This also takes place when switch 33 is on
(winter) if there is no demand for
heat to the central heating system or until
the room thermostat/time clock demands for
central heating circuit.
3.1 SAFETY DEVICE
In both central heating and domestic hot
water mode safe operating is ensured by:
A differential pressure switch shuts off the
main burner if the fan stops or the fl ue or
combustion air intake duct is obstructed
3.1.2 An overheat cut off thermostat set slightly
higher than the high limit thermostat acts
to turn of the burner to resetable “lockout”
(Fig. 50) item 3.
3.1.3 A safety valve is fi tted on the
central heating circuit set at
43 psi (3 bar).
3.2.1 A heating circuit (low water)
pressure switch is set at 0.4
bar.