Viessmann Vitocrossal 300 CU3A Application Manual page 53

Vitocrossal CU3A
Application 8 Operational Setup Instructions
This application consists of a low temperature heat circuit with motorized mixing valve, a hot water forced air fan
coil, indirect DHW and a 2-boiler cascade separated by a low loss header. This multi-boiler configuration offers
greater flexibility in system design as it allows for increased system turndown, boiler redundancy, increased
BTU inputs, and simultaneous operation of the heating and DHW. As the cascade control targets the maximum
temperature for the system, the mixing valve offers the added benefit of automatically adjusting the supply water
temperature regardless of the water temperatures being supplied to the other heat circuits. Since this is all con-
trolled by the cascade control, this makes for a simple, long lasting and efficient system. To set up this system,
follow the steps below:
Type/Option
Setup on each boiler
Setup On Cascade Control
Optional Adjustments
Set a Heating Schedule
Set a DHW Schedule
Set a DHW Recirculation Schedule for P2.1
Notes/Comments
1.
To enter service menu on the boiler you must hold
the "OK" and buttons for 5 seconds.
2. Setup wizard for the boilers and cascade controls
must be completed before proceeding with any
additional configurations.
3. To enter the service level of the cascade control,
press on the menu icon, select Service, and input
the following password: viservice.
To proceed to level 2 coding, select system
configuration icon, select coding 2 and input the
following password: viexpert
Step# Description
1 Set to multi-boiler mode
2 Set boiler number
3 Set LON participant number
4 Set boiler pump
5 Complete participant check
(For further instruction, refer to Installation & Service Manual)
6 Select system type
7 Set supply temperature of external demand
8 Set up HC2 outdoor reset curve
9 Set DHW temperature
Setup
Parameter Set to:
Location
Service Function -> Select Service
Multiboiler Application Menu
07: Set Boiler #
77: Set Boiler # Set in Level
2 Coding
0
37, 8a will need to
be set to 176
Service
Menu
00 :04
Set in Level
2 Coding
9B Set Temp.
Set In
Heating Sub
Menu
Heating Sub
Set In
Menu
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