Bosch Heatronic 4000 Installation & Operating Instructions Manual page 18

Flow Proof Demand Test --------------------------------
The control includes a flow proof test in order to determine if the
flow device has failed. A flow proof failure is detected if a flow
proof is present after the pumps have been shut off for more
than four minutes. This can occur if the flow proof device sticks
in the on position even when flow has stopped in the system.
A flow proof call error will latch when this condition exists.
Primary Pump Rotation -- ------------ ----------- --- ----- -- -------------------------------
The control rotates the pumps based on the primary pump
Rotate item in the Setup menu. Frequency of Rotation is based
on the running time of the pumps. Rotation is done when the
lead pump is off. If the lead pump runs continuously, the rotation
is delayed for up to 12 hours. If the pump runs continuously
& rotation is required, the control shuts off the lead pump & 1
second later the stand-by pump is turned on. This eliminates
overloading the pump electrical circuit. Upon turning on the
stand-by pump the flow proof call input is checked after the
flow proof call delay time.
Primary Pump Purge -- -------------- -------------- ------ -- ----------------------------------
After the last valid call is removed, the primary pump is operated
for an additional period of time. The purge period for the primary
pump is adjustable between 10 seconds & 20:00 minutes.
Boiler Pump Operation - -------------------------- ------- - ---------------------------------
The control includes relays to operate the boiler pumps.
Pre-purge
The control includes a boiler pump pre-purge which operates
the respective boiler pump for a period of time before the boiler
is ignited in order to purge potential residual heat out of the
boiler. The pre-purge time is determined from the boiler mass
setting. As the boiler mass setting is increased, the boiler pump
pre-purge time is also increased. The pre-purge time is fixed
at 4 seconds whenever a DHW Tank Call is provided in order
to reduce boiler pick-up times.
Post-purge
The control includes a boiler pump post-purge feature that
operates the respective boiler pump for a period of time after
the boiler is turned off. This feature will purge heat out of the
boiler & aid in reducing "kettling". The amount of time for the
boiler pump post purge is adjustable between 10 seconds &
20:00 minutes.
Pump Logic
The control includes a special pump logic feature for protection
against flue gas condensation due to cool water temperatures.
The pump logic feature considers a flow temperature condi-
tion applicable after turning on a boiler and a burner turn-off
condition applicable when turning off a boiler. The pump logic
feature is only applicable for Bosch / Buderus boiler models
that are non-condensing.
The control uses the boiler outlet sensor of the respective boiler
for the pump logic feature. If the boiler outlet sensor becomes
unavailable, the boiler will be locked out from operation.
For the flow temperature condition, a minimum temperature
of 122°F (50°C) must be reached within 10 minutes from the
time flame has been established within the boiler.
If the boiler outlet temperature reaches 122°F (50°C) within
10:00 minutes from the time flame has been established,
the boiler pump remains on and the burner is operated as
required to satisfy the Boiler Target temperature. If the boiler
outlet temperature then drops below 122°F (50°C), the boiler
Heatronic 4000
------------------------- ------- pump is turned off until the boiler outlet temperature reaches
the 122°F (50°C).
If the boiler outlet temperature does not reach 122°F (50°C)
within 10:00 minutes from the time flame has been established,
the boiler pump turns off. The boiler pump then remains off until
the boiler outlet temperature reaches 122°F (50°C).
For the burner turn-off condition, a minimum temperature of
129°F (54°C) is required in order for the burner to be turned
off. Also, for modulating boilers, the burner is adjusted to a
maximum of 60% rate prior to being turned off.
If the boiler outlet temperature of an applicable boiler is at
least 129°F (54°C) when it is required to be turned off, the
burner output is adjusted to 60% (for modulating burner). The
burner then turns off.
If the boiler outlet temperature of an applicable boiler is less
than 129°F (54°C) when it is required to be turned off, the
boiler pump is turned off and the output is adjusted to 60% (for
modulating burner) until the boiler outlet temperature reaches
129°F (54°C).
Indirect DHW (IDHW) Tank Pump Operation - ---- --- --- --
The control includes a relay to operate an indirect DHW
tank pump.
Operation of the IDHW tank pump is determined by the
Application Mode & the presence of an appropriate call.
Application Mode: Outdoor Temperature Reset,
Setpoint, Energy Management System
• DHW Call from Contact Closure.
• DHW Call from DHW Sensor.
Application Mode: Building Automation System
• BAS DHW Pump Call.
DHW Recirculation Pump Operation - --- ---- --- --- --- --- -
The control has the capability to operate a DHW Recirculation
Pump when the control is configured for either Indirect
Domestic Hot Water (IDHW) or Dedicated Domestic Hot
Water (DDHW). IDHW is available when the application
mode is set to either outdoor temperature reset, setpoint or
EMS. DDHW is available when the applicable mode is set
to DDHW. The Aux Relay setting in the Setup Menu must
be set to DHWR to enable the DHW recirculation pump.
The DHW recirculation pump operates continuously during the
Occupied period. If setback is enabled, the pump operates
when heat is required during the Unoccupied period.
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BTC461503101C | 6720810369 (2018/03)