Giacomini R298 Series Quick Start Manual

M
ixing valves
0529EN April 2015
T -
hree way mixing valve wiTh bonneT
r298
Description
The R298 mixing valve allows for the interception and mixing of heating fluid
in radiant heating and cooling systems for floors or ceilings and in medium-
size radiator heating systems that require precise control of water delivery
temperature. The R298 valve is equipped with a handwheel for manual
operation, or alternatively, it can be coupled to a K274 actuator for automatic
control.
Versions and product codes
Product code Connections
R298Y001 1 1/2" M x 1 1/2" F
R298Y027
1 1/2" M x 1 1/2" F
Completion codes
• Actuators K281 or K282
Accessories
• P19Y001: ring nut M30x1,5 mm for adapting valve R298 M28x1,5 mm
threading.
• P19Y002: ring nut M28x1,5 mm for adapting valve R298 M30x1,5 mm
threading.

Technical data

• Heating fluid: water for air-conditioning systems
• Max. working temperature: 90 °C
• Max. working pressure: 10 bar
• Maximum differential pressure: 1,2 bar
• Center distance: 120 mm
• Connections: 1 1/2" flat seat
• Mixing: by bonnet DN20, which is normally closed on the primary side
Materials
• Body, bonnet and nut in brass CW617N - UNI EN12165
• EPDM sealing rings
Losses of pressure
In Table 1, values in Kv and mixing percentage ratios (between the by-pass
"QBP" flow rate and the primary side "Qp") corresponding to the various
opening positions are displayed.
SYSTEM SIDE
BOILER ROOM
Qp
R298
Actuator connection Center distance [mm]
M28 x 1,5 mm
120
M30 x 1,5 mm
SYSTEM SIDE
clockwise
rotation
BOILER ROOM
SIDE
SYSTEM SIDE
BOILER ROOM
SIDE
Qbp
SIDE
1000
900
800
700
600
500
400
300
200
100
90
80
70
60
50
40
30
20
10
Table 1
Opening
Kv
Shutter
(direct + by-pass)
F.C. 3,25
0,5 mm
3,48
1 mm 3,79
2 mm 3,78
3 mm 3,12
4 mm 2,35
F.O.
1,78
Operation
R298 + handwheel for manual operation
The three-way R298 mixing valve is equipped with a handwheel to allow for
manual operation, which are carried out via a simple clockwise rotation for
the valve opening and anticlockwise for closure.
Total opening of the bonnet, and therefore of the primary side supply, is
obtained by screwing down the handwheel, while unscrewing it fully frees
the thread for the drive motor connection.
bypass
SYSTEM SIDE
anticlockwise
rotation
BOILER ROOM
SIDE
R298 + K281 actuator for automatic operation
The handwheel can be replaced with a K281 actuator for automatic mixing
adjustment, in combination with electronic thermoregulation. The K281
actuator is mounted manually, by screwing the brass ring nut in a clockwise
direction until it stops. This does not require the use of any tools.
bypass
SYSTEM SIDE
BOILER ROOM
SIDE
ISO ISO
OHSAS
9001 14001 18001
0006/7 0032A/3 0064L/1
F.O. 4 3 F.C.
0,5
1
2
Q [l/h]
Primary side By-pass
flow rate Qp flow rate Qbp
0 % 100 %
11 % 89 %
18 % 82 %
29 % 71 %
44 % 56 %
74 % 26 %
100 % 0 %
Direct
SYSTEM SIDE
clockwise
rotation
BOILER ROOM
SIDE
Direct
SYSTEM SIDE
BOILER ROOM
SIDE
anticlockwise
rotation
1