Viessmann VITOGAS 100 GS1 series Installation Instructions Manual page 24

Connections
Installation Examples
With 4-way mixing valve to regulate heating circuit
e.g. with Vitotronic 200, KW2 combined with a mixing valve actuator accessory kit
Underfloor heating system with system separation
24
(continued)
Heating circuit
Spring-loaded flow check valve
Circulation pump
Safety header
with automatic air vent,
pressure relief valve, and
pressure gage
Expansion tank
4-way mixing valve
Domestic hot water tank
(indirect-fired)
Bypass pipe with flow regulating
valve, for systems with large water
content (>1 USG/13 000 Btu/h / 15
ltr/kW/h of boiler input).
See page 28 for installation details.
Underfloor heating circuit
Spring-loaded flow check valve
Circulation pump for underfloor
heating circuit
Safety header
with automatic air vent,
pressure relief valve, and
pressure gage
Expansion tank
3-way mixing valve
Circulation pump for heat exchanger
Heat exchanger
Supply temperature sensor