Wilo Stratos Notice De Montage Et De Mise En Service page 30

English
8.3 Selecting the control system
Unit type
Heating-/ventilation- and
air conditioning systems
with a system friction loss
(heating radiator +
thermostatic valve) ≤ 25%
of the total resistance
Heating-/ventilation- and
air conditioning systems
with a system friction loss
in the generator/distributor
circuit ≤ 25% of the
resistance in the transfer
part (heating radiator +
thermostatic valve)
30
System conditions
1. Two-pipe systems with thermostatic/
zone valves
• Flow head > 13.1 ft (high head
systems)
• Very long distribution lines
• Heavily throttled branch shut-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
1. Two-pipe systems with thermostatic/
zone valves and high consumer
authority
• Flow head ≤ 6.6 ft (low head
systems)
• 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 heating systems with
thermostatic or zone valves
4. Single-pipe systems with
thermostatic or branch shut-off
valves
Subject to technical alterations!
Recommended
control system
Δp-v
Δp-c
WILO AG 05/2007