Viessmann Vitocrossal 300 Series Technical Data Manual page 16

Accessories
Accessories for Vitocrossal 300 CU3A
Fuel Conversion Label Kit (NG>LPG)
(included in boiler technical literature set)
The Vitocrossal 300 CU3A boiler comes factory set for
operation with natural gas. All Vitocrossal 300 CU3A
models can be field converted to operate with liquid
propane gas (as well as back to natural gas as required).
The kit includes instructions and labels for field conversion.
Low-Loss Header
When used in conjunction with the Vitocrossal 300
CU3A boiler, the low-loss header acts as hydraulic break,
decoupling boiler and system circuits from each other.
Viessmann recommends the use of a low-loss header
in cases where the system head and flow rates are
unknown.
The temperature sensor connection [TS] typically located
at the top of the low-loss header ensures low return
temperatures to the Vitocrossal 300 CU3A boiler at all
times, increasing operational efficiency.
IMPORTANT
Use only a Viessmann temperature sensor (accessory).
Do not use any other manufacturer's temperature sensor.
In addition, the low-loss header helps eliminate air and
debris [D] from the heating system.
See illustrations for design and principle of operation.
16
Vitocrossal 300 CU3A 26 to 199 Technical Data
Low-loss header design (Typical)
Legend
AB Air Bleed
BR Boiler Return
BS Boiler Supply
BY Bypass (with laminar flow)
D Debris and/or air
DV Drain Valve
SC Sensor Cable
SR System Return
SS System Supply
TS Viessmann Temperature Sensor
SW Sensor Well