CALEFFI 519 Series User manual

Function
The differential pressure by-pass valve is used in systems with a
fixed speed circulating pump supplying several zones controlled
by two way zone valves. This valve ensures that the head pressure
of the pump is proportional to the number of two way valves being
closed. It will bypass the differential pressure created by the pump
as the zone valves close, thus eliminating water hammer noise.
Product range
Code 519502A By-pass with flow up to9gpm. Size 3/4" MNPT
union inlet x 3/4" MNPT union outlet
Code 519599A By-pass with flow up to9gpm. Size 3/4" Sweat
union inlet x 3/4" Sweat union outlet
Code 519600A By-pass with flow up to 40 gpm Size 1" FNPT
inlet x 1" MNPT union outlet
Code 519609A By-pass with flow up to 40 gpm Size 1” Female
NPT x 1” sweat outlet
Code 519700A By-pass with flow up to 45 gpm Size11/4" FNPT
inlet x 1 1/4" MNPT union outlet
Code 519709A By-pass with flow up to 45 gpm Size11/4" FNPT
inlet x 1 1/4" Sweat union outlet
Technical characteristics
Materials
Body: brass
Valve plug: brass
Valve plug gasket: peroxide-cured EPDM
O-Ring seals: peroxide-cured EPDM
Union seals: asbestos free NBR
Control knob: ABS
Spring: stainless steel
Performance
Suitable fluids: water, glycol solutions
Max percentage of glycol: 30%
Temperature range: 32–230°F (0–110°C)
Maximum working pressure: 150 psi (10 bar)
Flow rates: 3/4” flow up to9gpm
1” flow up to 40 gpm
1 1/4” flow up to 45 gpm
Setting range: 1 - 6mw.g. (2-10 psi)
CALEFFI
Adjustable differential pressure by-pass valve with graduated scale
519 Series
38482.05
www.cale.com
©Copyright 2018 Calef fi
SAFETY INSTRUCTION
This safety alert symbol will be used in this manual to draw attention to safety related
instructions. When used, the safety alert symbol means ATTENTION! BECOME ALERT!
YOUR SAFETY IS INVOLVED! FAILURE TO FOLLOW THESE INSTRUCTIONS MAY
RESULT INASAFETY HAZARD.
These items are designed for use in closed hydronic systems. Do not use in plumbing
applications. These items do not meet the low-lead plumbing standards of U.S. and
Canada.
Code 519566A By-pass with flow up to9gpm. Size 3/4" press
union inlet x 3/4" press union outlet

Operating principle When the spring (1) compression is adjusted using the control
knob (2), the force balance acting on the valve plug (3) changes,
thus modifying the threshold pressure value
of the valve. The valve
plug opens, activating the by-pass circuit, only when it is subjected
to a di rential pressure su t to generate a thrust greater than
the thrust exerted by the spring. This allows the w discharge
through the outlet (4), limiting the di rence in pressure between
the two points in the system where the valve is
System operation
O = open
C = close
The job of the di erential pressure by-pass valve is to maintain the
pump operating point as close as possible to its nominal value (point
A on the graph shown below). If the by-pass valve is not used, when
the ow rate in the circuit decreases due to partial closure of the two-
way zone valves, the head loss in the circuit increases, point B.
The by-pass valve, set to the nominal head value of the pump,
limits the increase in pressure, by-passing the w rate ∆G. This
behavior is guaranteed at any closing condition of the system two-
way zone valves. In fact, once the position of the valve control
knob has been established, the threshold pressure value is more
or less constant as the discharge w rate varies (see hydraulic
characteristic diagrams).
A proper valve sizing must guarantee a su cient w rate by-pass to
keep the pump at its nominal operating point in all system operating
conditions, for example when the rst zone valves are closed.
1
2
3
4
5
Flow rate G
∆p
∆pNOMINAL
Pump curve
∆p constant
on the circuit
Circuit resistance curve
with two-way valves
partially open
Circuit resistance curve with
two-way valves fully open
A
B
∆G
50% 100%
Two-way
TOTAL LOAD
mH2O
1
2
3
4
5
6
PARTIAL LOAD
mH2O
1
2
3
4
5
6
O
O
O
O
O
O
C
O
O
C
C
O
CAUTION: All work must be performed by d personnel trained in the
proper application, installation, and maintenance of systems in accordance
with all applicable codes and ordinances.
CAUTION: Over-tightening and breakage can occur with the use of T ®
pipe joint compounds. T ®provides lubricity so that care must be
exercised not to over-tighten joints. Failure to follow these instructions
could result in property damage and /or personal injury.
WARNING: System s are under pressure or temperature can be
hazardous. Be sure the pressure has been reduced to zero and the
system temperature is below 100°F (38°C). Failure to follow these
instructions could result in property damage and/or personal injury.
WARNING: This product can expose you to chemicals including lead, which is
known to the State of California to cause cancer and birth defects or other
reproductive harm. For more information go to www.P65Warnings.ca.gov.

The dierential pressure by-pass valve can be tted in any position,
respecting the owdirectionindicated by the arrow on thevalve body.
In systems with a traditional boiler it is normally tted between the
system ow and return ends, which allows thecontrol of the pressure
and the passage of a minimum ow through the heatgenerator.
In systems withacondensation boiler, it is preferable to t the
by-pass directlybetween theupstream and downstream sections of
the pump,asthis allows a higher ∆T in the circuit, with lower return
temperatures and therefore better operation of the system.
In the event of highby-passow rate levels, it is recommended to t
the valve between the ow and return ends of each column, rather
thanttinganumber of valves in parallel at the central boiler.
mH2O
1
2
3
4
5
6
Installation
To regulate the valve, turn the knob to the required value on the
graduated scale:the values correspond to the dierential pressure in
psi or meters w.g. to open the by-pass.
For a quick setup adjustment of the dierential pressure by-pass
valve, use the following manual method. As an example, a hydronic
system with several zone valves: the system must be operating, the
zone valves must be fully open and theby-pass valve must be set to
the maximum value (a) (clockwise). Graduallyopen the dierential
pressure by-pass valve using the control knob (counterclockwise).
Useathermometer, or simply your hand,tocheck that the hot water
is owing into the by-pass circuit (b). As soon as a rise in the
temperature is noted, turn control knob (clockwise) one halfturn
closed so hot water stopsowing into the by-pass (c). Lock the knob
in this position (d) with the locking screw.
Adjustment
mH2O
1
2
3
4
5
6mH2O
1
2
3
4
5
6
a) b)
c
mH2O
1
2
3
4
5
6mH2O
1
2
3
4
5
6
c) d)
Hydraulic
characteristics
code 519502A, 519566A
519599A (3/4”)
∆p (psi)
1 2 0.5 0 1.5
G(m3/h) (gpm)
∆p (psi) (m w.g.)
0
1
2
3
4
5
6
7
0
10
1
2
3
4
5
6
7
8
9
11
0
10
1
2
3
4
5
6
7
8
9
11
1
5 4
3 2
6
7
8 9
0
2
4
6
8
10
Setting positions

Service Instructions
There is no service required for the dierential by-pass valves.
CAUTION: If the by-pass valve is not installed, commissioned and
maintained properly, according to the instructions contained in this
manual, it may not operate correctly and may endanger the user.
CAUTION: Make sure that all the connecting pipework is water tight.
Leave this manual for the user.
Caleffi North America, Inc.
3883 West Milwaukee Road
Milwaukee, WI 53208
T: 414.238.2360 F: 414.238.2366
∆p (m w.g.)
1 2 0
G
(m
3
/h) (gpm)
∆p (m w.g.) (psi)
0
1
2
3
4
5
6
7
0
10
1
2
3
4
5
6
7
8
9
11
5 0 10 15 25 20 30
3 4 5 6
40 35 45
7 8 9 10
8
0
1
2
3
4
5
6
7
8
code 519700A -
519709A (1 1/4”)
1
2
3
4
5
6
Setting positions
∆p (m w.g.)
1 2 0
G(m
3
/h) (gpm)
∆p (m w.g.) (psi)
0
1
2
3
4
5
6
7
0
10
1
2
3
4
5
6
7
8
9
11
5 0 10 15 25 20 30
3 4 5 6
40 35
7 8 9
8
0
1
2
3
4
5
6
7
8
code 519600A -
519609A (1”)
1
2
3
4
5
6
Setting positions
7-19-18
·
Installation Tip
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519 DPBV