Principle of Operation
A thermostatic mixing valve mixes hot and cold water in such a way as to maintain a constant set
temperature of the mixed water at the outlet. A thermostatic element is fully immersed into the mixed
water. It then contracts or expands causing movement of the piston, closing either the hot or cold
inlets, regulating the flow rates entering the valve.
If there are variations of temperature or pressure at the inlets, the internal element automatically reacts
attempting to restore the original temperature setting.
Thermal
Shutoff
The Caleffi 5231 series
mixing valves require a
minimum temperature
differential from hot inlet
to mixed water outlet of
20°F (11°C) to ensure
the correct operation,
and maximum pressure
difference between the
hot and cold inlet parts
no greater than 2:1 ratio.
Softened water use is
highly recommended as
the warranty is voided
if used on water with
hardness greater than
10 grains.
Recommended
flow rates for
temperature stability:
Flow curves
10
0.1
1
0.2
0.3
0.5
20
50
p
(psi)
10
2
3
5
20
0.1
1
0.2
0.3
0.5
(psi) (bar)
10
2
3
5
20
10
2
5
20
0.01
0.1
0.02
0.03
0.05
1.0
0.2
0.3
0.5
4
0.4
0.4
4
0.04
0.4
50
10
0
10
0
20
0
1 ¼"
1 ½"
2"
4.4
8.8
40
70
Min.
Max.
(gpm) (gpm)
10
0.1
1
0.2
0.3
0.5
20
50
∆
p
(psi)
G
(l/min)
(
gpm
)
10
2
3
5
20
0.1
1
0.2
0.3
0.5
(psi) (bar)
10
2
3
5
20
10
2
5
20
0.01
0.1
0.02
0.03
0.05
1.0
0.2
0.3
0.5
4
0.4
0.4
4
0.04
0.4
50
10
0
10
0
20
0
G
(l/min)
(
gp
m
)
1”
523060A
523068A
1/2” - 3/4”
1”
2
24
Min.
Max.
(gpm) (gpm)
1"
7
7.6
13
14.2
Cv
1-1/4”
1-1/2” 2”
HOT
MIXED
COLD
.1
0.23
2.3
0.46
0.69
1.15
.3
1
∆p
(ft of head)
G
(l/s
) (
gp
m
)
23
4.6
6.9
11.5
46
0.1
1
0.2
0.3
0.5
(psi) (bar)
10
2
3
5
20
10
2
5
20
0.01
0.1
0.02
0.03
0.05
1.0
0.2
0.3
0.5
9.2
0.92
0.4
4
0.04
0.4
50
100
1.5
3.25
1”
1 1/2”
2”
1 1/4”
∆p
50
160
6
10
2.0
5.0
115
172
75
Flow should never exceed standards for pipe size and material.
