Ravenheat CSI 85 - Manual (Page 7)

7
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 hot 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 Select (fi g. 35) 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 Select (fi g. 35) 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 with the summer/
winter switch if there is no demand for
heat to the central heating system or
until the room thermostat/time clock
demands from the central heating circuit
the main burner fan and pump turn off
immediately. .
2.5 SAFETY DEVICE
In both central heating and domestic hot
water mode safe operating is ensured by:
2.5.1 A differential pressure switch which shuts off
the main burner if the fan stops or the fl ue or
combustion air intake duct is obstructed.
An overheat cut off thermostat set slightly
higher than the high limit thermostat acts
to turn of the burner to resetable “lockout”
(Fig. 35) item 3.
2.5.2 A safety valve is fi tted on the
central heating circuit set at
43 psi (3 bar).
2.5.3 A heating circuit (low water)
pressure switch is set at 0.4
bar.
Fig. 3
OVERALL DIMENSION