Ravenheat CSI 85, Installation And Servicing Instructions, Page: 6 / 55

2.4
2.4.1
2.4.2
2.4.3
Domestic hot water mode
2.4.4
The heat exchanger in the D.H.W. circuit is
built into the main heat exchanger, and do-
mestic water is heated by converting the wa-
ter in the central heating circuit. The trans-
ference of heat is very high because the two
fluids move in a counter direction flow to
each other.
Switch 33 in the
(winter) position,
When a hot water tap is turned on a di-
aphragm diverter valve excludes the central
heating circuit, the boiler automatically mod-
ulates 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.
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.
2.4.5
3.1
OVERALL DIMENSION
3.1.2
When D.H.W. is no longer called for the boil-
er automatically returns to the central heat-
ing mode.
Switch 33 in the (summer) position. The
boiler functions like an automatic gas hot
water heater. When D.H.W. is no longer re-
quired the main burner fan and pump imme-
diately 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.
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 flue or
combustion air intake duct is obstructed.
An overheat cut off thermostat set slightly
higher than the high limit thermostat acts to
turn off the burner to resetable “lockout”
(Fig. 50) 3.
3.1.3 A safety valve is fitted 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.