TDMA CONTROL 602-702 Eng Nov.doc
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5.6
Functions for operating domestic hot water system
(Set Hot water)
5.6.1
Time controlled heating of the hot water supply
Main Menu 12:34
Set Hot Water
If the temperature of the store top sensor falls below the minimum set value, the
hot water back up heating and boiler On/Off functions are activated. The
minimum temperature can be raised as a one off via, for example, the
circulation and bath button. Hot water back up heating can also be
overridden at particular times via an integrated time switch.
The boiler On/Off is activated by the hot water back-up heating requirement
as well as by heating demand. The back-up heating is only activated by a hot
water back-up heating demand.
Hot Water Charge
Targ Temp : 30...80 °C
When the ‘store top sensor’ reaches the set “Hot water heating set-point
temperature” the outputs ‘DHW heating’ and ‘boiler On/Off’ are switched off
and the loading of the hot water volume is complete.
Hot Water Charge
Hysteresis: 2...10 K
The hysteresis for the DHW back-up heating can be set here. If for example, a
DHW required a temperature of 60 °C and a hysteresis of 5 K are chosen, the
contacts for the DHW back-up heating and the Boiler On/Off will close when
the temperature reaches 55 °C and switches them on. When the temperature
reachs 60 °C the contact opens and switches off the back up heating
requirement.
Note:
Be aware of Legionella Regulations
Hot Water Charge
Min Temp: 0...80 °C
The hot water back up heating minimum temperature can be set here. The
DHW temperature will not fall below this minimum temperature, even when the
time switch is off.
Hot Water Charge
Overrun: 1..10 min
The hot water back-up heating function will continue to run for the set time
period after the set point has been reached. This function allows the thermal
store to be loaded above the minimum hot water demand volume. This
reduces the number of stop/start operations of the boiler, thereby prolonging
its life.
Optimised Hot Water Charge
Yes / No
This function can reduce the boiler run time for hot water heating and thus the
fuel consumption. If the “optimised hot water back-up heating” option is set to
“Yes”, the hot water target temperature will be calculated by the controller as
a function of the store bottom temperature.
If the store bottom temperature is high, the hot water setpoint will automatically
be reduced.
