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| Demand Rapid owner & installer guide 12949-B 02-19
Filling and draining
IMPORTANT
Do not turn on the pump or system until the cylinder is completely full of water. Damage to
the system as a result of not following this instruction will void any warranty.
Filling
1. Flush the cold water inlet pipe to remove any debris before final connection to the cold water
inlet of the Demand Duo cylinder.
2. Ease the TPR valve open to expel air while the cylinder is filling with cold water.
3. Slowly open the cold water expansion valve on the cold water supply pipe.
4. Allow the cylinder to fill.
5. Check all connections for water leaks and tighten as required.
6. Prime circulating pump before start up.
7. The thermostat on the Demand Duo cylinder is set to 65 °C and the Rinnai INFINITY is set to
75 °C. If the cylinder thermostat does not appear to be set correctly the thermostat may need to
be reprogrammed—contact Rinnai for assistance.
If hotter water is required the cylinder and the Rinnai INFINITY dip switches will need to be
adjusted.
8. Plug 3-core flex into suitably earthed general power outlet (GPO). Turn on power supply. The
thermostat will display the current water temperature in the cylinder, the pump should start and
the Rinnai INFINITY unit should ignite.
9. The Rinnai INFINITY unit will continue to operate until the thermostat reaches 65 °C. Once the
set temperature has been reached the thermostat will turn off the primary circulating pump.
10. When the storage water heater temperature drops below 60 °C the controller switches on the
recirculation pump, which ignites the INFINITY to reheat the water.
Draining
1. Isolate power supply to the Demand Rapid system.
2. Close the cold water isolation valve.
3. Ease the TPR valve open to expel air.
4. Remove cap on the cold water drain valve if no drain line is fitted.
5. Connect a hose or something similar to allow water to drain to a safe location.
6. Open cold water drain valve and allow water to drain from the system.
