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Bosch Buderus SSB255 | SSB399 | SSB512 Boilers
Control Operations Guide
03.2018
|
Bosch Thermotechnology Corp.
Data subject to change
6 Domestic Hot Water
6.1 Domestic hot water settings
Parameter
Description
DHW Mode
(parameter #35)
When an Indirect tank is present in the system set DHW Mode to “1” when using the factory supplied 10K ohm
sensor or set to “2” if using a third-party aquastat. Default value is “0” (Off ).
DHW Tank Hyst. Down
(parameter #36)
The necessary temperature drop of the indirect tank temperature needed before the boiler will begin to recover the
tank. Only active when DHW Mode (par. #35) is set to “1” and a 10k ohm sensor is used. Default value is 7.2°F.
Adjustable between 36°F. Only applies to systems using a 10k ohm thermistor (Parameter #35 DHW Mode = “1”)
DHW Tank Hyst. Up
(parameter #37)
The necessary temperature overshoot of the indirect tank temperature needed before the boiler will stop heating
the indirect tank. Default value is 0°F. Adjustable between 0°F and 36°F. Only applies to systems using a 10k ohm
thermistor (Parameter #35 DHW Mode = “1”)
DHW Tank Supply Extra
(parameter #38)
The Target Supply Water temperature to the indirect coil is equal to DHW Tank Setpoint (par. #48) + DHW Tank
Supply Extra.
DHW Priority
(parameter #42)
Default setting is “0” - Timed DHW Priority. Timer starts when there is both a DHW and a call for heat. See DHW
Priority Time (par. #43) for adjusting the length of time priority is given over a call for heat. Setting a value of “1”
gives DHW unlimited priority over a call for heat. Setting the value to “2” gives a call for heat unlimited priority over a
call for domestic hot water
DHW Max Priority Time
(parameter #43)
Default DHW priority [see DHW Priority (par.#42)] time is 30 minutes Adjustable from 1 to 255 minutes.
DHW Pump Overrun
(parameter #44)
Length of time the DHW pump contacts remain energized after a call for DHW has ended. Default setting is 15
seconds. Adjustable between 0 and 255 seconds.
DHW Tank Setpoint
(parameter #48)
Target temperature of the indirect tank. Default value is 120°F. Adjustable between 104°F and 140°F.
Table 11