User Guide

Installation and operating instructions Wilo-Stratos /-D/-Z 27
English
8.3 Selecting the control system
Unit type System conditions Recommended
control system
Heating-/ventilation- and
air conditioning systems
with a system friction loss
(heating radiator +
thermostatic valve) d 25%
of the total resistance
1. Two-pipe systems with thermostatic/
zone valves
• Flow head > 13.1 ft (high head
systems)
• Very long distribution lines
•Heavily throttled branch sh
ut-off
valves
•Branch differential pressure
regulator
• High pressure losses in those
system parts through which the
total volume flows (boilers/
refrigerating machines, poss. heat
exchangers, distribution line)
2. Primary circuits with high pressure
losses
'p-v
Heating-/ventilation- and
air conditioning systems
with a system friction loss
in the generator/distributor
circuit d 25% of the
resistance in the transfer
part (heating radiator +
thermostatic valve)
1. Two-pipe systems with thermostatic/
zone valves and high consumer
authority
•Flow head d 6.6 ft (low head
s
ystems)
• Converted gravity systems
• Retrofitting to large temperature
spread (e.g. long-distance energy)
• Low pressure losses in the system
parts through which the total
volume flows (boilers/refrigerating
machines, poss. heat exchangers,
distribution line)
2. Primary circuits with low pressure
losses
3. Underfloor hea
ting systems with
thermostatic or zone valves
4. Single-pipe systems with
thermostatic or branch shut-off
valves
'p-c