Wilo Stratos-D Series - Selecting the Control Mode

Installation and operating instructions Wilo-Stratos/-D/-Z/-ZD 81
English
8.3 Selecting the control mode
System type System conditions Recommended
control mode
Heating/ventilation/air-
conditioning systems with
resistance in the transfer
section (room radiator +
thermostatic valve)  25%
of the total resistance
1. Two-pipe system with thermostatic/
zone valves and virtually no user
authority
•H
N
> 4 m
• Very long distribution lines
• Strongly throttled shut-off valves
for pipe sections
• Sectional differential pressure
control
• High pressure loss in system parts
through which total volume flows
(boiler/refrigerating machine, any
heat exchanger, distribution line up
to 1st branch)
2. Primary circuits with high pressure
loss
p-v
Drinking water circulation
systems with resistance in
the generator circuit  50%
of the resistance in the
ascending section
3. Drinking water circulation systems
with thermostatically controlled line
shut-off valves
Heating/ventilation/air-
conditioning systems with
resistance in the generator/
distribution circuit  25%
of the resistance in the
transfer section (room
radiator + thermostatic
valve)
1. Two-pipe system with thermostatic/
zone valves and high user authority
•H
N
 2 m
• Converted gravity heating systems
• Conversion to large temperature
spread (e.g. district heating)
• Low pressure loss in system parts,
through which total volume flows
(boiler/cooling machine, any heat
exchanger, distribution line up to
1st branch)
2. Primary circuits with minor pressure
loss
3. Floor heating systems with thermo-
static or zone valves
4. One-pipe systems with thermostatic
valves or shut-off valves for pipe
sections
p-c