Installation Instructions
Commissioning | 27
6 720 805 218 (2016/02)SB625WS/SB745WS
Example DHW demand (where the 4000 series controls the DHW
system):
Sum of the set DHW temperature (140 °F) and parameter "Boiler rise"
(40 °F) in the "DHW" menu:
140 °F+ 40 °F = Maximum temperature demand 180 °F
Example heating circuits (where the 4000 series controls the
heating circuits):
Add of the set temperature of the heating circuit with mixing valve with
the highest temperature required (15 °F) and parameter "Boiler rise"
(160 °F) in the "Heating circuit data" menu:
160 °F+ 15 °F = Maximum temperature demand 175 °F
Notes on setting third party control units
• The third party control unit (building management system or PLC
controllers) must ensure a maximum internal boiler water
temperature that is sufficiently different from the high limit safety
cut-out. It must also be ensured that the digital burner controller
rather than the boiler water temperature regulator switch the burner
on and off.
• The control unit must ensure that the burner is switched to low load
before being shut down.
• Select control equipment that allows a gentle start-up with a time
delay when the system is cold.
• After the burner demand, an automatic timer (for example) should
limit the burner to low load for a period of approx. 180 seconds. This
restricted heat demand will prevent uncontrolled starting and
stopping of the burner.
• It must be possible to show the number of burner starts on the
control unit used.
6.2 Hydraulic connection to the heating system
▶ If the system temperatures are different, use both return connectors
3 (high temperature) and 2 (low temperature)(chapter 2.9.3.
Fig. 5 and 6,page 11, table 6, page 12)
▶ Connect heating circuits with high return temperatures to connector
3, and heating circuits with low return temperatures to connector 2.
▶ Restrict the water flow rate in the boiler to a temperature difference
of at least 7 K between supply and return.
▶ Size the pumps correctly.
▶ Before connecting the boiler, flush sludge and dirt out of the heating
system.
▶ Ensure that no oxygen enters the heating water during operation.
▶ Only operate the boiler in sealed unvented systems.
6.3 Hydraulic flow through boiler
The SB Series does not require a minimum flow rate in order to maintain
warranty. The boiler has been designed to operate with a temperature
difference between the supply and return of up to 100 °F. Flow should
be initiated with the start of the burner to minimize temperature
fluctuations and control deviations. The field installed manual reset high
limit (as required by CSD-1) must be fitted to the instrument bulb/probe
socket of the heating supply, set to 210 °F and electrically connected
into the Logamatic 4321 safety circuit terminals (17,18) or the burner
enable/disable circuit directly (see Fig 26).
Fig. 26
[1] Instrument bulb/probe socket of the heating supply
NOTICE: System damage due to incorrect sensor
position!
Safety cut-out and thermostat sensors of third party
control units must be fitted in the instrument bulb/probe
socket of the heating supply (Fig. 1[6], page 5) of the
boiler.
▶ Do not change the length of the immersion sleeve.
Unit Value
Temperature control unit s 40
Monitor/limiter s 40
Minimum difference between burner on and
off temperatures
K 7
Table 14 Conditions of use
For an optimum energy yield, we recommend supplying
a flow rate of 10 of the total nominal flow rate via the
low temperature flange, with a return temperature below
the dew point.
If there are no varying return temperatures, only the low
temperature flange needs to be connected.
Restriction of the temperature difference is not
necessary if the system is equipped with a dirt trap
device.
High flow rates and oversized pumps can result in the
accumulation of sludge or deposits on the heat
exchanger surfaces.
1
6 720 805 218-61.1T