Operating Conditions - Viessmann Vitomax HW Series Operating And Service Instructions

Operating conditions

Operating conditions
1. Heating water flow rate
2. Boiler return temperature
(minimum value)
Gas operation:
■
Oil operation:
■
3. Minimum flow temperature
4. Max. temperature spread
Gas operation:
■
Oil operation:
■
5. Stepped burner operation
6. Modulating burner operation
7. Reduced mode
Single boiler system
Multi boiler system
Lead boiler
■
Lag boiler
■
Weekend setback
Tab. 14
Note
Boiler types M92, M94 and M96 can also be operated
with fuel oil S (heavy fuel oil).
Boiler types M70 (boiler size 3 - 9), M72 and M74 can
similarly be operated with fuel oil S following conver-
sion (option incurs additional charge).
Note
For combustion of heavy fuel oil to DIN 51603-5, the
average boiler water temperature must be at least
90 °C.
24
M70A M72B
Requirements/notes
No minimum heating water flow rate required
Operation with minimum flow temperature
Operation with minimum flow temperature
Lag boilers can be shut down
See reduced mode
Boiler datasheet
"Requirements and standard values for water
quality" see page 11
M74B M92A M94B
65 °C
65 °C
70 °C
50 K
50 K
None
None
M96A