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Siemens Building Technologies Basic Documentation LMU54... / LMU64... CC1P7494en
HVAC Products 3 Functions 07.11.2002
The maximum pump speed (QmodMin) will be used (with the exception of full charging
of stratification storage tank systems).
If the LMU... knows about the states of the switching program, it is possible to run the
heating circuit pump at minimum speed during night setback or quick setback.
Decisive for this function is the compensation variant used.
In that case, it is accepted that the room temperature drops below the nominal level.
Energy savings are given priority.
Parameterization offers the following choices:
KonfigRg7.DtRedBetrieb =
XX0X XXXX: ∆T control is inactive in reduced mode, which means that the pump’s
speed is «NqmodMin»
XX1X XXXX: ∆T control is also active in reduced mode
Information about night setback is dependent on the compensation variant of heating
circuit 1. Depending on the variant, the function is either locked or released:
Compensation variant HC1 Criterion for night setback
Emergency operation, fixed value control or
weather compensation LMU...
Time switch is used and has made setback:
«KonfigRg1.Schaltuhr1» = 1
and
RT = 0
Room influence RU or weather compensation RU
Switching program of HC1 is in night setback
mode:
«BetrNiveauRh1»= 0 er 1*
* BetrNiveauRh1 = 0 means frost protection
BetrNiveauRh1 = 1 means reduced mode (this means that the minimum pump speed
is also used in frost protection mode)
If the criteria for night setback are not met, ∆T control will be calculated and the
calculated pump speed delivered.
If the LMU... knows about active boost heating, it is possible to deliver the maximum
pump speed during boost heating (thus ensuring the shortest heating up time).
Information about boost heating is only possible in connection with the QAA73...:
Condition for evaluating boost heating:
Compensation variant Hz = (room influence RU or weather compensation RU) and
QAA73... present.
On completion of boost heating, the degree of modulation from the calculation of ∆T
control will be delivered again.
Depending on the connected plant components, the maximum flow temperature setpoint
«teta_vl_max» is generated based on the input from several sources:
Emergency operation, fixed
value control, weather
compensation LMU...
Room influence RU,
weather compensation RU
Compensation variant HC1
TkSnorm
(setting parameter of LMU…)
MaxTSet
(setting of RU)
DHW operation
Behavior with night setback
or quick setback
Behavior with boostheating
Maximum limitation of the flow
temperature in connection
with ∆T control
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