Domestic Hot Water Settings
RELAY BOARD SETTINGS
HOW TO CONNECT DOMESTIC HOT WATER CONTROL
To enable Domestic Hot Water (DHW) control select YES under HOT WATER in the
relay setting page (See Figure 16). The system will then engage Relay 2 if there is a
demand for DHW. Therefore, you must connect the DHW pump/valve to Relay 2.
If HOT WATER is set to YES you will also be prompted to select RELAY 1 CALL. If
set to YES, Relay 1 (Boiler relay) will trigger together with Relay 2 when there is a
demand for DHW to fire the boiler and generate the required heat. However, if
you use a zone valve with an auxiliary end switch for controlling the DHW (typically
found in S type Plan heating systems) you will use the NO contact from a valve to
trigger Relay 1 instead of the software. In this case RELAY 1 CALL should be set to
NO. FIG 12. shows how valves with auxiliary switches are connected.
CONNECTION OF THE SENSOR
Connect the DHW sensor to connections 1, 2 and 3 on the SE1 board by plugging
it into the correct position. Place the sensor head in a designated pocket that can
accompany a 6 mm sensor on the DHW tank or surface mount the sensor on the
outside of the tank, make sure the sensor is properly connected to the tank for
accurate readings.
If the sensor is not connected you will still be able to use schedule and control
the DHW zone based on time but you will not be able to control the DHW
temperature. In that case, you should connect a DHW cylinder thermostat in
series with relay 2 output to make sure that there is an actual need for DHW.
Regardless if the sensor is connected or not, It is always recommended to instal
a high limit thermostat if there is a danger of overheating. This is to prevent
the DHW from reaching dangerous temperatures and to prevent scalding and
potentially system damage. See Figure 21 for wiring example of DHW thermostat
and/or high limit thermostat.
