RDG603A20 - Issue 10
Page 45 of 100
With the engine quickly up to
operating temperature, the first 71°
thermostat opens. The water now
flows to the domestic hot water tank,
resulting in hot water being rapidly
available.
When the water stored in the hot water
tank has reached full temperature, the
second 88° thermostat opens and
water can then flow to the skin tank
and correctly control engine cooling.
The exhaust manifold that earlier
helped to heat engine water is now
cooled to ensure safe operation and
reduce engine compartment
temperatures.
If the load on the engine reduces and
the demand for domestic hot water
increases then the system will
automatically compensate and re-
direct water to ensure that a plentiful
supply of hot water is always
available.
Figure 22: Twin Thermostat Operation
