AERMEC NRB 0282 Series, Руководство по установке и обслуживанию

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VARIABLE FLOW RATE SYSTEMS ON THE PRIMARY CIRCUIT WITH HYDRONIC KITS W1-W2-W3-W4
Configurations W1-W2-W3-W4 are designed for single-ring systems with a
variable flow rate.
BENEFITS
This type of system produces:
• a simplified hydraulic circuit
• lower electricity consumption for pumping
WHAT THEY INVOLVE
These options include as standard:
(fig.1)
• Pumping units with high or low head, with the pumps driven by an
inverter
• Differential pressure transducer and absolute pressure transducers:
pressure sensors for ensure flow rate modulation based on the
pressure difference measured between two precise points indicated
on the hydraulic diagram
• Bypass branch with a motorised valve to ensure the minimum flow
rate required by the heat exchanger in all operating conditions
HOW THEY WORK
The system that this solution is applied to must have a certain number of
terminals with 2-way valves (On-Off or Modulating) that vary the flow rate
during adjusted operation.
During the system design phase, make sure there are an adequate number
of terminals with 3-way valves (not subject to flow rate variation on the
supply), to guarantee the minimum flow rate on the circuit compatible
with the machine limits.
The system automatically modulates the number of pump rotations - and
therefore the water flow rate - on the basis of the pressure difference
measured on the unit (and resulting from the opening or closure of the
2-way valves).
IT is essential to guarantee terminal regulation systems that, during
modulation, envisage an overall flow rate variation less than 10% per
minute of the current flow rate.
(fig.2)
Be sure to respect the minimum water content (refer to the
“System water
content”
chapter).
Hydraulic circuit confi guration W3
The diff erential pressure transducer (4) is
located on the rear of the unit, near the
two absolute pressure transducers (16), so
it can be accessed for maintenance. The
diff erential pressure transducer (4) is the
starting point for the capillaries that are
then connected to the evaporator inlet
and outlet, as indicated in the hydraulic
diagrams on the following pages.
COMPONENTS PROVIDED AS STANDARD
1
Plate heat exchanger
2
Water temperature sensors
3
Antifreeze electric heater (standard in the heat exchanger and storage tank)
4 Diff erential pressure transducer
5 Air vent valve
6
Water fi lter
7
Pump
8
Drain valve
9 Cut-off valve
10 System buffer tank
11
Expansion Tank
12
Safety valve
13
Pressure gauges
14 Flow switch
15 Motorized by-pass valve
16 Pressure transducer
VARIABLE FLOW RATE SYSTEMS ON THE PRIMARY CIRCUIT WITH HYDRONIC KITS W1-W2-W3-W4