Honeywell DU146 User Manual
AUTOMATIC BYPASS AND DIFFERENTIAL PRESSURE
VALVE WITH DIFFERENTIAL PRESSURE INDICATOR
Design
The bypass and differential pressure valve comprises:
• Body with internally threaded inlet and outlet
• Spring bonnet
• Display tube for differential pressure indication
• Adjustment facility
• Valve disc
• Spring
Materials
• Unpolished brass housing
• High-grade synthetic material spring bonnet
• High-temperature resistant synthetic material display tube
• High-quality synthetic material adjus ter knob
• Brass valve disc
• Stainless-steel spring
• EPDM seals
DU146
PRODUCT DATA
Application
The DU146 automatic bypass and differential pressure valve
is used to maintain constant differential pressure in a heating
system. It reduces flow noise in a system, particularly as
thermostatic radiator valves are closing. The boiler return
temperature is raised and this reduces the corrosion caused
by flue gas condensation. In addition, when radiator valves
are closed it also maintains flow over the temperature sensor
on the boiler to ensure proper operation of external temperature compensating controls. On gas fired water heaters it
guarantees a minimum flow circulation when thermostats or
radiator valves are closed.
Features
• Simple installation between the flow and return pipe-
work
• Minimises flow noise
• No external controls required
• Differential pressure finely adjustable
• Simple adjustment using the integral differential
pressure indicator
• Hinders boiler corrosion
• Setting value is in meters water column
• Tried and tested
Range of Applicati on
For pumped hot water heating systems
Specifications
Medium
Operating temperature
Operating pressure
Differential pressure
Connection size
Hot water
max. 110°C (230°F)
max. 3,0 bar (43,5 P.S.I.)
Adjustable between
0,05...0,5 bar (0,7...7,3 P.S.I.)
Set during manufacture at 0,2 bar
(2,9 P.S.I.)
3/4" and 1 1/4"
Copyright © 2002 Honeywell AG • All rights reserved EN0H-0181GE25 R0402
DU146
Function
At equal pressure between the inlet and outlet side the valve
is closed. The valve disc is pushed by a spring against the
valve seat. If there is a pressure difference between the inlet
and outlet sides, then a force is exerted on the valve disc and
against the spring. If this force exceeds the force of the
spring, then the valve begins to open in proportion to the rise
in differential pressure and maintains a constant bypas s flow
as indicated on the flow diagram.
Versions
A = Standard version
Special versions on request
Dimensions for installations 90/70 up toType R
L I H h ca. kW approx. kcal/h
3/4" 36 50 160 100 70 60 000 DU146-3/4 A
1 1/4" 51 58 213 155 232 200 000 DU146-1 1/4 A
Ordering-No.
Accessories
Complete indicator tube
For DU146 differential
pressure and bypass
valve.
Comprising: Indicator
tube, spring, indicator
piston and 5 ‘O’ rings
DU146AH-A
EN0H-0181GE25 R0402 2 Honeywell AG • All rights reserved
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