ECKELMANN WRG 3010 E, Инструкция по эксплуатации, Страница: 19 / 113

Firmware V1.4 20.05.2021 19/113
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5.1 High Temperature Heat Recovery HT
The HT heat recovery functional unit consists of a heat exchanger, a hot gas valve, a water pump and the
associated temperature sensors. There must always be 2 temperature sensors for hot gas (inlet, outlet) and 2
temperature sensors for water (inlet, outlet).
When a higher-level BMS requests it via digital input 2 (terminals 52/53) and after a switch-on delay of 150
seconds has elapsed, the calculation of the internal power signal starts. An exception to this is the button "HT
Off" , which is located on the "WRG 3010 E" visualisation. If this has been tapped, the internal power
calculation is also suppressed. There are two ways to calculate the internal power signal; for details, see
Power Signal .
If the internal, calculated power signal reaches the "Desuperheat ON" threshold, (see figure " Visualisation in
LDSWin - HT / LT / Power Signal Setpoints "), the water pump starts. The speed control is activated immediately
and depends on the spread between the water outlet temperature and the water inlet temperature of the heat
exchanger:
If the spread is below the setpoint, the pump delivers more slowly.
If the spread exceeds the setpoint, the pump delivers faster.
Furthermore, a minimum speed and a maximum speed can also be set for the pump.
If there is a collective fault message from the pumps at digital input 6 (terminals 60/61: Message appears when
the input is de-energised), this is forwarded to the system centre as an alarm. In this case, the pump is not
switched off, as electronic pumps would otherwise not be able to be switched on again without further action.
As soon as the pump is running (and there is no fault from it), the hot gas valve is activated. The valve directs
the hot gas into the heat exchanger, where it releases its energy to the water. The valve reports both end
positions back to the controller, where "closed" stands for bypassing the heat exchanger and "open" for
introducing the hot gas into the heat exchanger. The feedback of the valve must also always match its control. If
this is not the case, an alarm is sent to the system centre. Due to different run times of the installed valve
actuators, there is a waiting time of 260 seconds when switching over, during which no alarms are issued.
The following monitoring devices are available and lead to a forced closure of the hot gas valve; the pump
continues to run:
A flow monitor in the water circuit which is read via digital input 19 (terminals 86/87: "Good" state when
voltage is applied)
. If the flow monitor trips for at least 1 minute , the hot gas valve is forcibly closed and an
alarm is issued.
An optional pressure transmitter which is read via analogue input 3 (terminals 42/43) and compared with a
limit value. If the measured pressure falls below the limit value continuously for an adjustable time, it must
be assumed that there is no longer sufficient water in the system. Then the hot gas valve is forcibly closed
and an alarm is issued. This option must be selected and its settings configured; for details
see picture
"Setpoints HT LT power signal" .
The flow and return temperatures are monitored and if an adjustable limit value is exceeded, the hot gas
valve is forcibly closed and a prio 0 message is issued. The hot gas valve is not enabled again until the
value falls below the triggering limit value by 3 Kelvin.
The high temperature heat recovery HT is an option and does not have to be present in all systems.
The prerequisite for this operating mode is that this function has been selected in the visualisation; for
details see figure
"HT, LT power signal setpoints" .
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A digital request and an analogue power signal are always required for operation!
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