Danfoss BW10 020-090, Инструкции по установке, эксплуатации и обслуживанию

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Legend
O Open
F Closed
Water inlet
Water outlet
Pressure gauge
If the pressure drop has increased, this indicates that the screen
filter must be removed and cleaned, as the hydronic circuit
contains solid particles. In this case close the shutoff valves at
the water inlet and outlet and remove the screen filter after
emptying the hydronic section of the unit.
Renew, if necessary, to ensure that the filter is not conta-
minated.
When the circuit is cleaned, read the pressures at the unit (entering
water pressure - leaving water pressure), expressed in kPa to find
out the plate heat exchanger pressure drop.
Compare the value obtained with the theoretical selection
value. If the pressure drop measured is higher than the value
specified this means that the flow rate in the plate heat
exchanger (and thus in the system) is too high. The pump
supplies an excessive flow rate based on the global pres-sure
drop of the application. In this case close the control valve one
turn and read the new pressure difference.
Entering water pressure reading
Leaving water pressure reading
O
F F
O
F
F
Example: Unit with a given nominal flow rate of 4.8 l/s
Water flow rate, l/s
Legend
1 Unit pump curve
2 Plate heat exchanger pressure drop (to be measured with the pressure gauge
installed at the water inlet and outlet)
3 Installation pressure drop with control valve wide open
4 Installation pressure drop after valve control to obtain the specified flow rate
Pr
essur
e dr
op
, kP
a
1
2
3
4
0
25
50
75
100
125
150
175
200
2
4 6 8 10
Proceed by successively closing the control valve until you
obtain the specific pressure drop that corresponds to the
nominal flow rate at the required unit operating point.
• If the system has an excessive pressure drop in relation to
the available static pressure provided by the pump, the
resulting water flow rate will de reduced and the difference
between entering and leaving water tempe-rature of the
hydronic module will be increased.
To reduce the hydronic system pressure drops, it is necessary:
• to reduce the individual pressure drops as much as
possible (bends, level changes, accessories, etc.)
• to use a correctly sized piping diameter.
• to avoid hydronic system extensions, wherever possible.