Electromechanical cold controls for refrigerators and freezers · 2021. 3. 11. · solenoid valves in dual temperature cabinets. The changeover contact withstands a max. load of 1.2

Electromechanical cold controls for refrigerators and freezers

danfoss.com

16/96A for US-market

2

Electromechanical cold controls for refrigerators and freezersIntroduction"Danfoss Appliance Controls with its headquarter and manufacturing site in Zlaté Moravce - Slovakia, is the oldest and most experienced manufacturer of mechanical thermostats in the world - with over 65 years of experience and more than 400mill produced items." Through extensive product and process development over the last 35 years Danfoss has developed

highly automated production facilities ensuring homogeneous products with high quality standards, being considered the bench mark within its business segment.

All our products are approved by recognised authorities and produced according to the last update of RoHS.Only RoHS compliant Supplier of raw material is in use for our product.

Danfoss Appliance Controls is best characterized as a stand-alone business unit, meaning that the organization has full global business responsibility across regions, no need for multiple contact persons or confirmation steps, we value our customers and are able to set-up the right team to meet their needs.

Application – Function description page 3

Type description page 5

Data – Design page 6

Approvals – ISO certification – Dimensions page 7

Testing – Thermostat selection – Accessories page 8

Range of standard and service thermostats page 9

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Danfoss 077Z thermostat is used to control the temperature in household refrigera-tors, upright and chest freezers as well as in light commercial cabinets such as liq-uid coolers, bottle coolers and ice cream cabinets. The thermostat can be used as an evaporator thermostat or a room ther-mostat.

Danfoss does not take responsibility for the use of these thermostats in applications involving specialty products (e.g. high-value products), life-science materials or biologics. Danfoss recommends protect-ing those applications with a built-in safe-ty backup control, electronic thermostats, alarms or monitoring.

The thermostats are available with normal function, fixed cut-in and cut-out tem-perature, constant or variable cut-in tem-perature for automatic defrost.

The thermostats can be supplied with the following supplementary functions:

• Change-over contact • Enclosed Brake Device contacts for appli-

ances charged with flammable refriger-ants

All thermostats have NC (Normally closed) main contacts; i.e. they cut out the com-pressor current circuit on decreasing tem-perature.

• Cut-out temperature for variable cold con-trols ranges from 5 °C–20 °C (41 °F – 68 °F) and 0 °C (32 °F) for constant ones (Range is defined as the interval between cut-out temperature in position cold and warm).

• Differential of normal function thermostat is between 4.5 °C (40 °F) and 15 °C (59 °F), all in position warm (Differential is inter-val between cut-in and cut-out tempera-ture).

• Differential of automatic defrost thermo-stat with constant or variable cut-in above 0 °C (32 °F) is between 10.5 °C (51 °F) and 40 °C (104 °F) in position warm. (Differen-tial is interval between cut-in and cut-out temperature).

• With automatic defrost the cut-out tem-perature ranges between -5 °C (23 °F) and -42 °C (-43 °F), the cut-in temperature be-tween 1 °C (34 °F) and 11 °C (52 °F).

• Other temperature settings can be sup-plied by arrangement.

• 6.3 x 0.8 mm, 4.8 x 0.8 mm(0.25 x 0.03 in, 0.19 x 0.03 in) or a combination of above dimensions of terminals.

• Wide range with various accessories, see page 8.

Application

GeneralDanfoss 077Z thermostats are designed for temperature control in refrigerators and freezers. The thermostat regulates by cutting off or cutting in current to the compressor. Depending on the tempera-ture registered by the thermostat sensor, the thermostat controls the compressor by powering it (cut-in) or depowering it (cut-off). The thermostat can be used either as an evaporator thermostat or a room thermostat. The thermostat body must not be exposed to condensate or defrost water.

MountingTo ensure the best function, it is important to ensure that the sensor (capillary tube end) makes good contact with the evapo-rator; or, in room thermostat applications, with the airflow. The sensor must always be placed colder than the remaining sec-tion of the capillary tube and the thermo-stat itself. To secure trouble-free operation, Danfoss provides the customer with a ther-mostat drawing (dimension sketch), speci-fying among other things the recommend

ed sensor mounting length “LS”. For further details, please contact your Danfoss Sales Representative, or our website www.danfoss.com. The thermostat body must not be exposed to condensate or de-frost water.

OperationOn thermostats with a spindle, the temper-ature is adjusted to cold by turning it clock-wise (from warm towards cold position). Both cut-out and cut-in temperatures can be changed by turning the spindle, except on type 077Z6, where only the cut-out temperature can be changed in this way.

Function description

°C

Cut-inrange

TemperatureintervalCut-out

range

Warm Middle Cold

Di�erential

Dan

foss

77B5

7.12

°C

0

TemperatureintervalCut-out

range

Warm Middle Cold

Dan

foss

77B5

8.11

4

All normal function thermostats have a cut-out temperature range and a cut-in tempera-ture range. The differential is defined as the difference between cut-in and cut-out temperatures. However, the temperature settings of fixed function thermostats are non-adjustable. On thermostats with constant cut-in temper-ature, 077Z6 type, the terms “differential” and “cut-in temperature range” do not apply. The only relevant terms are “cut-out temperature range” and “temperature interval”.

The thermostats can be divided up into the following main types:

1. Thermostat with normal function, type 077Z0.

2. Thermostat with changeover function, type 077Z04.

3. Refrigerator thermostat with automatic defrost and constant cut-in temperature, type 077Z6.

Function

Danfoss 077Z thermostat types

Type Functionality description

Z0 Without additional functionality

Z04 With changeover contact

Z6 With constant cut-in temperature and automatic defrost

The reversing switch (terminal 6) (changeover contact) is mainly used to control 3/2-way solenoid valves in dual temperature cabinets. The changeover contact withstands a max. load of 1.2 A NI (resistive) or x0.2 A (inductive).

Refrigerator thermostats with a cut-in temperature between 2 °C (36 °F) and 11 °C (52 °F) are used in automatic defrost systems. The evaporator de-ices during every compressor stop time.

Thermostats with the Danfoss Enclosed Brake Device (EBD) are being assembled inside household appliances charged with flammable refrigerants such as R600a (isobutene) or R290 (propane) to prevent explosions due to leakage.

PerformanceDanfoss 077Z thermostats are designed to operate at least 100,000 cycles at full load (16/96 A). Cut-out temperature setting drifts should be anticipated.

Safety backup control (Redundant thermostat) Danfoss 077Z thermostats are designed for fridges and freezers in household- and light commercial appliances. Within the high-price food sector and/or medical coolers, Danfoss recommends protecting comestible goods by operating applianc-es with a built-in safety backup control or Danfoss electronic thermostats.

For further information, please contact your Danfoss Sales Repre sentative or visit our website www.danfoss.com.

Dan

foss

90U

32.1

2

43Dan

foss

77B2

13.1

0

θPos.

°C

Warm Middle Cold

Cut-out

0

Cut-in

Dan

foss

77B2

07.1

0

θPos.

°C

Warm Middle Cold

Cut-in

Cut-out

Dan

foss

90U

22.1

2

3 4

Dan

foss

90U

33.1

2

4

63

5

Function Operation mode

Current marking

Type Contact USA/Canada

V AC FLA LRA

Z0 3-4 120 16 96

Z043-43-6

120120

161,2 A

96NI

Type description

Type Z0Without extra functionality

Type Z04With changeover contact

Function Operation mode

Current marking

Type Contact USA/Canada

V AC FLA LRA

Z6 3-4 120 16 96

Type Z6With constant cut-in temperature and automatic defrost

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Data – Design

Temperature interval -42 °C – 11 °C (-43 °F – 52 °F)

Cut-out temperature range 5 °C – 20 °C (41 °F – 68 °F)

Differential 3 °C – 40 °C (37 °F – 104 °F) (depending on spindle position and type)

Constant cut-in temperature 1 °C – 11 °C (34 °F – 52 °F) (type 077B6 only)

Barometric pressure As default 760 mm Hg (1013 hPa), others on demand

Mounting To be mounted with nut or bracket (clip)

Connection terminal6.3 x 0.8 mm, 4.8 x 0.8 mm,(0.25 x 0.03 in, 0.19 x 0.03 in) or any combination of both

Capillary tube length

Standard lengths: 0.8 m, 1.0 m, 1.2 m(32 in, 39 in, 47 in)Customized lengths: 0.6 m – 2.9 m(24 in - 114 in)PE coated tubes: 0.6 m – 2.3 m(24 in - 91 in)Lengths out of above range by arrangement with Danfoss

Ambient temperature -25 °C – 65 °C (-13 °F – 149 °F)

Humidity <90% RH (non-condensing)

Weight For capillary tubes longer than 2.3 m(91 in) please contact Danfoss

Deviant barometric pressure adjustment can be provided in accordance with cus-tomer requirements. An optional PE coat-ing offers capillary tube protection where requested.

The code number is laser printed on the thermostat. If required, the thermostat can be supplied marked with the customer code number, cut-in and cut-out temperatures in

positions “warm” and “cold”, as well as data matrix marking.

The first row indicates the thermostat’s cut-in temperature in positions “warm” and “cold”.

The second row indicates the Danfoss ther-mostat type and cut-out temperatures in positions “warm” and “cold”.

The third and fourth row respectively indi-cates the customer code, data matrix mark-ing (optional) as well as EBD marking (when specified).

The fifth row provides the Danfoss process code, code number and production week/year/batch information.

Technical data

Design details

Dan

foss

77B6

6.11

7 86 1112 10 1

32495

1. Earth tab 2. Contact system complete 3. Connection tab 4. Differential screw 5. Main arm 6. Bellows element 7. Capillary tube/sensor 8. Main spring 9. Cut out screw 10. Spindle 11. Nut 12. Range curve

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Approvals – ISO certification - Dimensions

Electromechanical cold controls are generally classified as individual components, also when assembled in refrigeration appliances. Hence some regional authorities stipulate cold controls to be subject to an individual approval. All 077Z thermostats are approved by the following authorities:

UL in USA and Canada

Approvals

Dimensions

All measurements in mm

ISO certification Danfoss Appliance Controls are certified by Bureau Veritas in ISO14001, ISO9001 and OHSAS18001.

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When selecting a thermostat, the following three factors must be taken into considera-tion: 1. The temperature conditions in the refrig-eration appliance 2. Pressure equalization during standstill periods 3. Compressor capacity utilisation Satisfactory conditions can be achieved by observing the following guidelines:

The thermostat range determines the tem-perature level in the refrigerator or freezer. The range selection must be consistent with avoidance of short operating times in “warm” position.

With the thermostat in “cold“ position, in high ambient temperatures and under high load, the thermostat cut-out function must remain operational. This can be achieved by setting the cut-out temperature about 2 °C (36 °F) higher in relation to the temperature that can be reached. In case a permanent compressor run time is required in “cold“ position, the cut-out point should be set 2 °C (36 °F) colder than the temperature that can be reached.

In general, a cut-out temperature range of 10°C (50°F) is suitable for most refrigerators and freezers. The differential should exceed a minimum range to secure the refrigera-tion system’s full pressure equalization; oth-erwise, the restart of e.g. compressors equipped with LST starting devices may be impeded.

The experience-based Danfoss recommen-dations given below indicate some appli-ance-specific minimum differentials in posi-tion “warm”: Refrigerators 8-10 °C (46 °F – 50 °F)Chest freezers 8-10 °C (46 °F – 50 °F)Upright freezers 5-7 °C (41 °F – 45 °F)Liquid and bottle approx. 4,5 °C (39 °F)coolers

In order to find the best cold control variant, multiple appliance tests need to be per-formed. Danfoss provides its customers with valuable application notes providing, for example, relevant information on sensor and cold control placement. For further information, please contact your Danfoss Sales Representative or visit our website www.danfoss.com.

Danfoss offers a wide range of different accessories in various colors, including items like dial plates, washers and knobs. For more information, please contact your Danfoss Sales Representative or our website www.danfoss.com.

Thermostat selection

Accessories

Testing - Thermostat selection – Accessories

Testing All Danfoss 077Z thermostats pass multiple hardware and operational tests to ensure that cut-in and cut-out temperatures are properly adjusted. A Danfoss test certificate may be provided free of charge.

To ensure sustained control precision, the submerged part of the sensor (LS) is cooled down/heated up at speed of only 0.5 ±0.1 °C /minute (1 °F ± 0.2 °F /minute). Both cut-in and cut-out temperatures are mapped with

the controls closing and opening the main contact respectively. To enhance the perfor-mance of the controls, this process is per-formed twice and only the second reading applies.

When evaluating temperature settings, the barometric pressure discussed above has to be taken into consideration.

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Range of standard and service thermostats

Service thermostats 077Z7010

16 – 96 A EBD

3 4

Cut-in

+9

+38

+28

+19

Off Warm MiddleSetting pos.

Cold

Cut-out

°F

Length of capillary (in): L = 39(airsensor)


16 – 96 A EBD

3 4

Cut-in

+17

+41

+29.5

+23.5

Off Warm MiddleSetting pos.

Cold

Cut-out

°F

Length of capillary (in): L = 84Min. sensor length mounted on evaporator (in): LS = 6(Used as airsensor min. 2 x LS)

Service thermostats 077Z7012 Service thermostats 077Z7013



Cut-in

+3

-14

+36

+26

+9

+21.5

Off Cold

Cut-out

°F

Warm MiddleSetting pos.

Cut-in

+3

-14

+36

+26

+9

+21.5

Off Cold

Cut-out

°F


16 – 96 A EBD

3 4

16 – 96 A EBD

3 43 43 4

10









Cut-in

-18.5

-29

+9.5

+3

-11

-3

Off Cold

Cut-out

°F


Cut-in

+25.5

+10

+47

+36.5

+25

+37.5

Off Cold

Cut-out

°F


16 – 96 A EBD

3 4

16 – 96 A EBD

36

4

16 – 96 A EBD

3 4

16 – 96 A EBD

3 4

Cut-in

-11

-25.5

+16.5

+7

-7.5

+4

Off Cold

Cut-out

°F


Cut-in

-18.5

-29

+9.5

+3

-11

-3

Off Cold

Cut-out

°F


3 4 3 4

3 4

Electromechanical cold controlsfor refrigerators and freezers

VisionWe want to be a significant leading global provider of cold controls and cold control solutions for the appliance industry, and therefore contribute to the success of our customers.

We will be respected in our environ-ment, and among our owners, custom-ers and employees, for what we do, and how we do it.

We will be a highly efficient and lean organization generating maximum profits through economics of scale and sublime quality products.

MissionOur Mission is to be the world’s premier provider of cold controls, cold control solutions and services within the business area household and light commercial appliances, offered to the global market of OEMs and wholesal-ers, in order to fulfil their needs for components, solutions and added value.

Our competitiveness is based on world class quality, knowledge, customer service and support.

We will work according to our Citizen-ship Principles in such a manner to be recognized as the most respected, safe and reliable manufacturer of cold controls in the world.To support our mission, we are guided by our commitment to continuously value enhancement, policies, princi-ples, and beliefs that guide our work every day.

AD280540041598en-US0201/ 520U0023 © Copyright Danfoss Appliance Controls | AK | 09 2019

“077Z....EBD, 077Z….L EBD can be applied on system with R290 and R600a as the working fluid.Always adhere to local codes and safety guidelines. For countries with no conformity certification (UL, CE, CCC, CSA, EAC, etc.) requirements on new systems, Danfoss recommends third party approval for systems containing flammable refrigerants.”

Danfoss can accept no responsibility for possible errors in catalogues, brochures and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products already on order provided that such alterations can be made without subsequential changes being necessary eady agreed.All trademarks in this material are property of the respective companies. Danfoss and the Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.

Documents

Electromechanical cold controls for refrigerators and freezers · 2021. 3. 11. · solenoid valves in dual temperature cabinets. The changeover contact withstands a max. load of 1.2