Scu 224 And 345 ∆T Control With Temperature Limitations; Speed Control With Solar Control Module Sm1 - Viessmann VITOSOL 200-FM SV2F Design Manual

Solar System Design Guide
SCU 224 and 345 ∆T Control with Temperature Limitations

Speed Control with Solar Control Module SM1

This function is used for loading or unloading tanks.
The control will monitor both tanks to see if there is
usable heat that can be utilized. The control has 3 sets
of criteria that must be achieved before the heat
exchange will occur.
1. The heat source must be greater than the defined
minimum temperature or Switch ON temperature
setpoint.
2. The heat source must be greater than the heat sink
as defined by the Switch ON temperature differential
(or ∆T).
3. The heat sink must be lower than the defined
maximum temperature or Switch OFF temperature
setpoint.
Note: If the system temperature is within this criteria,
the heat exchange will begin. It will continue until
one or more sets of criteria have not been achieved.
■ Upper and lower temperature limits
■ Differential temperature control
∆T controls
The corresponding relay switches ON if the ∆Ton
(startup) temperature differential is achieved and
OFF when the thermal load maximum temperature is
exceeded.
The variable speed pump control is disabled in the factory
default condition, during commissioning it can be enabled
for relay output R1.
Possible pumps:
– High efficiency pumps (with optional module)
– Pumps with PWM input (only use solar pumps),
e.g. Wilo or Grundfos pumps
Note: We recommend operating the solar circuit pump at
maximum output while the solar thermal system is
being commissioned and vented of air.
Solar Control
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