Caleffi 5231 User Manual

Thermostatic mixing valves,
low-lead, high-flow

5231 series

CALEFFI

ACCREDITED

ISO 9001 FM 21654

ISO 9001 No. 0003

01256/14 NA

Function

The thermostatic mixing valve is used in systems producing domestic
hot water or in radiant heating systems. Its function is to maintain the
temperature of the mixed water supplied to the user at a constant set
value when there are variations in the supply pressure and temperature
of the incoming hot and cold water or in the flow rate.

The 5231 series thermostatic mixing valves are ASSE 1017 approved for
point of distribution and are designed specifically for systems requiring
high flow rates and precise, stable temperature control.

ASSE 1017

Product Range

Code 5231_0A Thermostatic mixing valve (ASSE 1017) with threaded connections.........................................................sizes 1”, 1-1/4”, 1-1/2”, 2” union NPT male

Code 5231_8A Thermostatic mixing valve (ASSE 1017) with sweat connections................................................................... sizes 1”, 1-1/4”. 1-1/2", 2" union sweat

Code 523177A Thermostatic mixing valve (ASSE 1017) with sweat connections and outlet temperature gauge..................................... sizes 1-1/4” union sweat

Technical specification

Materials: - Body: Low-lead brass

- Shutter: PPSG40

- Springs: Stainless steel

- Seals: EPDM

Suitable fluds: Water, glycol solutions
Maximum percentage of glycol: 30% glycol solution
Setting range:
See table on page 3
Temperature stability: ± 3°F (± 2°C)
Max working pressure (static): 200 psi (14 bar)
Max operating differential pressure: 70 psi (5 bar)
Hot water inlet temperature range: 120 – 195°F (49 – 91°C)
Cold water inlet temperature range: 39 – 80°F (3.9 – 26.6°C)
Mixed temperature range: 95 – 150°F (35 – 66°C)
Maximum inlet pressure ratio (H/C or C/H): 2:1
Minimum temperature difference between hot water inlet
and mixed water outlet for optimum performance: 20°F (11°C)
Maximum water hardness: 10 grains
Certifications:

1. cUPC Listed to ASSE 1017/CSA B125.3. Reduction of
Lead in Drinking Water Act Compliant: 0.25% Max.
weighted average lead content. Reduction of Lead in
Drinking Water Act Certifed by IAPMO R&T.

2. Meets requirements of ANSI/NSF 372-2011.

Dimensions

C

B B

F

A

D

HC

A

E

Sweat version

110

130

90

D

F

70

E

50

30

150

170

190

210

A

A

Code A B C D E F Wt (lb)

523160A 1" NPT 4" 8" 7 5/8" 4 3/16" 3 3/8" 7.0

523168A 1" SWT 3 5/16" 6 5/8" 7" 3 1/2" 3 3/8" 7.0

523170A 1 1/4" NPT 4 1/8" 8 1/4" 7 3/4" 4 5/16" 3 3/8" 7.1

523177A 1 1/4" SWT 3 3/8" 6 3/4" 7 5/8" 4 1/8" 3 3/8" 8.5

523178A 1 1/4" SWT 3 3/8" 6 3/4" 7" 3 1/2" 3 3/8" 7.1

523180A 1 1/2" NPT 5 1/8" 10

523188A 1 1/2" SWT 4 1/16" 8 1/8" 8 1/8" 4 3/8" 3 3/4" 17

523190A 2" NPT 5 1/8" 10

523198A 2" SWT 4 5/16" 8 5/8" 8 5/8" 4 7/8" 3 3/4" 18

1/4" 9 3/16" 5 7/16" 3 3/4" 17

1/4" 9 1/2" 5 3/4" 3 3/4" 18

A

“Legionella” - Scalding risk

Principle of Operation

In systems producing domestic hot water
with storage, in order to avoid the dangerous
bacteria known as ”Legionella”, the hot
water must be stored at a temperature of at
least 140°F. At this temperature it is certain
that the growth of the bacteria causing this
infection will be totally eliminated. However,
at this temperature the water cannot be
used directly, as it may cause scalding. For
example, at 130°F, partial burning takes
place in 30 seconds and at 140°F total
burning takes place in 5 seconds.
In view of the above, it is necessary to install a
thermostatic mixing valve which can

· reduce the temperature at the point of use
to a value lower than that of storage;

· maintain this value when the incoming
pressure and temperature conditions
vary.

Thermal disinfection

The diagram below shows the behavior of
the bacteria “Legionella Pneumophila” when
the temperature conditions of the water
in which it is contained vary, in laboratory
sample population.
In order to ensure proper thermal
“disinfection”, the value must not be below
140°F.

:

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

In the event of a failure of either the hot or cold supply, the piston will shut off, stopping water
discharging from the mixed water outlet.
The Caleffi valve requires a minimum temperature differential from hot inlet to mixed water outlet
of 20°F (11°C) to ensure the correct operation of the thermal shutoff feature.

Construction details

Double seat

The mixing valve has a special actuator which acts on a double water passage seat. This
produces a high flow rate with a reduced resistance, at the same time maintaining accurate
temperature control.

Anti-wear surfaces

The materials of construction in the 5231 series thermostatic mixing valve eliminates the
problem of jamming caused by mineral deposits. All the working parts, such as the PPSG40
shutter and EPDM seals, are made of a special anti-scale material, with a low friction coefficient,
providing long term high performance.

Low inertia thermostat

The temperature-sensitive element, the “motor” of the thermostatic mixing valve, is characterized
by a low heat inertia; this means that it reacts rapidly to variations in the incoming temperature
and pressure conditions, reducing the valve response times.

Temperature setting and locking

The control knob permits temperature setting, between min. and max., in one turn (360°). It
also has a tamper-proof system to lock the temperature at the set value.

160
140
120
100

80
60

32

Reference documents

For the prevention and control of Legionella,
see the National Regulations and applicable
Code of Practice.

Kills bacteria instantly
Kills 90% of bacteria in 2 minutes

Kills 90% of bacteria in 2 hours

Optimum temperature
for growth of bacteria

Surviving bacteria inactive

COLD

HOT

MIXED

Use

Min 1234567Max

77 84 91 102 109 118 126 136 149

Pos.

T (ϒF)

with: T

HOT

= 155ϒF (68ϒC) · T

25 29 33 39 43 48 52 58 65T (ϒC)

Caleffi 5231 series thermostatic mixing valves are designed to be installed at the hot
water heater (ASSE 1017 models).

ASSE 1017 models are designed to be installed at the hot water heater and cannot
be used for tempering water temperature at fixtures as a point-of-use valve. They
are not designed to provide scald protection or anti-chill service and should not be
used where ASSE 1070 devices are required. Wherever a scald protection feature is
required, ASSE 1070 model mixing valves need to be installed. For safety reasons, it
is advisable to limit the maximum mixed water temperature to 120°F.

Instantaneous production of hot water

Caleffi 5231 series thermostatic mixing valves should not be used in conjunction
with boilers giving instantaneous production of domestic hot water. This would
compromise the correct operation of the boiler.

Radiant heating systems

Caleffi Series 5231 thermostatic mixing valves can also be used for controlling the
flow temperature in radiant heating systems, for constant and accurate control with
ease of installation.

Installation

Before installing a Caleffi 5231 series thermostatic mixing valve, the system must be
inspected to ensure that operating conditions are within the range of the mixing valve,
checking, for example, the supply temperature, supply pressure, etc.
Systems where the Caleffi 5231 series thermostatic mixing valve will be installed must
be drained and cleaned out to remove any dirt or debris which may have accumulated
during installation. Failure to remove dirt or debris may affect performance and the
manufacturer’s product guarantee. Demineralized water use is highly recommended
as the warranty is voided if used on water with hardness greater than 10 grains.
The installation of filters of appropriate capacity at the inlet of the water from the supply
line is always advisable.
The water must be sufficienctly treated before it enters the valve in areas with highly
agressive water. Caleffi 5231 series thermostatic mixing valves must be installed in
accordance with the diagrams in this manual, taking into account all current applicable
standards.
Caleffi 5231 series thermostatic mixing valves can be installed in any position, either
vertical or horizontal.
The following are shown on the thermostatic mixing valves body:

- Hot water inlet, color red.

- Cold water inlet, color blue.

- Mixed water outlet, marked “MIX”.
In systems with thermostatic mixing valves, check valves must be installed to prevent
undesirable fulid backflow. The 5231 is approved to ASSE 1017, and as such does
not contain integral check valves, so those must be sourced separately. It is essential
that access to the valve is totally unobstructed for any maintenance which may be
required to the valve or connections. The piping from/to the valve must not be used
to support the weight of the valve itself.

Commissioning

After installation, the valve must be tested and commissioned in accordance with the
instructions given below, taking into account current applicable standards.

1) The system must be clean and free from any dirt or debris
before commissioning the thermostatic mixing valves. Be sure water hardness
is less than 10 grains.

2) It is recommended that the temperature is set using a suitable calibrated
digital thermometer. The valve must be commissioned by measuring the
temperature of the mixed water at the outlet.

3) The maximum outlet temperature from the valve must be set taking account
of the fluctuations due to simultaneous use.

4) Adjust the temperature using the adjusting knob on the valve.
For safety reasons, it is advisable to limit the maximum mixed water
temperature to 120°F in domestic hot water systems.

Temperature setting

The temperature is set to the required value by means of the knob with the
graduated scale, located on the top of the valve.

Caution: In systems with thermostatic mixing valves,
check valves must be installed to prevent undesirable
fluid backflow. The 5231 models do not contain integral
check valves, and must be sourced separately.

Locking the setting

Position the knob at the required value,
unscrew the top screw, slide off the knob and
put it back in such a way that the handle fits
into the internal slot of the knob. Tighten the
head screw

.

3

1

M

I

2

N

M

A

X

7

Point of Distribution ASSE 1017 Approved

Size

1" NPT 523160A 4.4 40 7

1" Sweat 523168A 4.4 40 7

1 ¼" NPT 523170A 4.4 40 7.6

1 ¼" Sweat w/ temp 523177A 4.4 40 7.6

1¼" Sweat 523178A 4.4 40 7.6

1 ½" NPT 523180A 8.8 70 13

1 ½" Sweat 523188A 8.8 70 13

2" NPT 523190A 8.8 70 14.2

2" Sweat 523198A 8.8 70 14.2

*Recommended flow rates for temperature stabilty: ± 3°F (± 2°C).

Setting the temperature

The temperature is set to the required value by means of the adjusting
knob with the graduated scale on the top of the valve.

Flow curve

∆

p (psi)

20

10

5
4

3

2

1

0.5

0.4 0.4

0.3

0.2

0.1

2

.1

Connection

1” 1 1/2” 2”

5

.3

Model

104

95
35

109

40 43 47 50 54 58 61 66

10

1

117

1 1/4”

20

1.5

Min.

Flow*

(GPM)

122

129

136 142 150

INLET

50

3.25

Max.
Flow*
(GPM)

∆p

(psi) (bar)

20

10

5
4

3

2

1

0.5

0.3

0.2

0.1

)

100

gpm

G

(l/s) (

CV

1.0

0.5

0.4

0.3

0.2

0.1

0.05

0.04

0.03

0.02

0.01

Applications diagrams

712

M

MIN

A

X

HOT
RED

MIX

COLD

BLUE

Radiant heating system application

SUPPLY

HOTCOLD

7
X
A
M

MIN

1

2

MIX

CALEFFI

CALEFFI

I

I

F

F
F

F
E

E
L

L
A
C

CA

10

10

10

10

10

10

8

8

8

8

8

8

6

6

6

6

6

6

4

4

4

4

4

4

2

2

2

2

2

2

0

0

0

0

0

0

CALEFFI

CALEFFI

RETURN

Recirculation with point-of-distribution thermostatic mixing valves

For domestic recirculating systems that include a single ASSE 1017
point-of-distribution thermostatic mixing valve, such as the Caleffi
5231 series thermostatic mixing valves, the piping installation below
is recommended.

In any reciculating hot water distribution system there will be times
when the circulator is operating, but no hot water is being drawn at
the fixtures. Under this condition, heat continually dissipates from
the piping forming the recirculation loop. If the loop is relatively
short, and well insulated, the rate of heat loss should be very small.
If the loop is long, and uninsulated, the rate of heat loss could be
substantially greater.

To maintain the recirculating water at the desired delivery temperature
the heat lost from the loop must be replaced. This requires some
water flow between the loop and the hot water source. Ideally, this
flow is adjusted so that the rate of heat trasfer from the hot water
source to the loop exactly balances the rate of heat loss from the
loop's piping.

The figure (below right) shows a "bypass valve" (1), and "return
valve" (2), which regulates how much warm water from the return
side of the recirculating loop flows back to the storage tank. When
there is no demand for hot water at the fixtures, the flow of return
water to the tank will equal the rate of hot water flow from the tank to
the inlet port of the mixing valve. Ideally, this flow should be adjusted
so that the rate of heat transfer from the tank to the recirculating

loop exactly balances the rate of heat loss from the recirculating
loop. This allows the water temperature leaving the mixing valve to
remain stable.

The bypass valve (1) and possibly the return valve (2) must be
adjusted when there is no domestic water draw on the recirculating
loop (when all the fixtures are off). Begin with the bypass valve
(1) fully closed, and the return valve (2) fully open. Turn on the
recirculating circulator and let it run for several minutes. The supply
water temperature leaving the mixing valve will likely be lower than
the setting of the valve, since there is no return flow to the tank.

Slowly open the bypass valve (1) and monitor the temperature
leaving the mixing valve. It will likely begin rising as some water
returns to the tank, and an equal flow of hot water moves from
the tank to the hot port of the mixing valve. When the temperature
leaving the mixing valve remains stable, and is at or very close to the
temperature set on the mixing valve, the bypass valve is correctly
set.

The return valve (2) can remain fully open unless a situation occurs
where the bypass valve (1) is fully open, but the temperature leaving
the mixing valve is still too low. If this occurs, partially close the
return valve (2) to add flow resistance. This forces more flow through
the bypass valve (1). Repeat the previously described procedure
of slowly opening the bypass valve (1) until the water temperature
leaving the mixing valve is stable.

Radiant loop

Key to symbols

Safety relief valve

Check valve

Isolation valve

Expansion vessel

Filter

Pump

Globe Valve

Domestic water system with recirculation

STORAGE

HOT WATER

HEATER

T

7
X
A
M

N
MI

1

2

2

1

SPECIFICATION SUMMARIES

5231 series

Adjustable thermostatic mixing valve. cUPC Listed to ASSE 1017/CSA B125.3. Threaded NPT or sweat connections from 1” to
2” with unions and tailpieces. Low-lead brass body (<0.25% lead content) certified by IAPMO R&T. Meets requirements of ANSI/
NSF 372-2011. PPSG40 shutter, stainlless steel springs, and EPDM seals. Maximum working pressure 200 psi (14 bar). Maximum
operating differential pressure 70 psi (5 bar). Mixed temperature setting range 95 to 150°F (35 to 66°C), Temperature stability
± 3°F (± 2°C). Maximum water hardness: 10 grains. Provided with tamper-proof temperature locking. Provide with optional mixed
outlet temperature gauge for 1 1/4" union sweat model, 30 to 210°F scale, 2 inch diameter.

We reserve the right to change our products and their relevant technical data, contained in this publication, at any time and without prior notice.

Caleffi North America, Inc.
3883 W. Milwaukee Road
Milwaukee, WI 53208
Tel: [phone] · Fax: [phone]
[e-mail] · www.caleffi.com/usa/en-us
© Copyright 2014 Caleffi North America, Inc.