Danfoss MTCV Data sheet

Data sheet

Multifunctional Thermostatic Circulation Valve MTCV - Lead free brass

Introduction

Fig. 1

Basic version - A

The MTCV is a multifunctional thermostatic balancing valve used in domestic hot water installations with circulation.

The MTCV provides a thermal balance in hot water installations by keeping a constant temperature in the system, thus limiting the flow in the circulation pipes to the minimum required level.

To meet the increasing demands placed on the quality of drinking water, Danfoss MTCV valves are made from corrosion resistant and Lead Free materials:

Main functions of the MTCV • Thermostatic balancing of hot water systems

within the temperature range of 35 - 60 °C version A.

• Automatic (self-acting) thermal disinfection at temperatures above 68°C with safety protection of the installation to prevent the temperature rising above 75 °C (automatically shuts-off circulation flow) - version “B”.

• Automatic disinfection process, electronically controlled, with the possibility of programming the disinfection temperature and duration - version “C”.

•

Automatic flushing of the system by temporarily lowering the temperature setting to fully open the MTCV valve for a maximum flow.

• Temperature measurement possibility.

Fig. 2 * Self-acting version with automatic disinfection function - “B”

* thermomete r is an accessory

Fig. 3

Version with electronically controlled disinfection process - “C”

• Valve body made from rg5 bronze material

• Components made from no Lead Brass

• Main cone made from advanced engineering polymere POM-C.

Simultaneously, the MTCV can realize a disinfection process by means of 2 features:

• An automatic (self-acting) disinfection module - thermo-element (fig.2).

• An electronic controller with thermal actuator TWA and temperature sensors PT1000 (fig.3).

• Preventing of unwanted tampering.

• Constant temperature measurement and monitoring - version “C”.

• Shut-off function of the circulation riser by means of optional fittings with a built-in ball valve.

• Modular upgrading of the MTCV valve during operation, under pressurized conditions.

• Servicing - when necessary the calibrated thermo-element can be replaced.

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Data sheet MTCV - Lead free brass

Function

Fig. 4 MTCV basic version - A

The MTCV - is a thermostatic self-acting, proportional valve. A thermo-element (fig. 6 elem. 4) is placed in the valve cone (fig. 6 elem. 3) to react to temperature changes.

When increases the water temperature above the set point value, the thermo-element expands and the valve’s cone moves towards the valve seat, thus limiting circulation flow.

When decreases the water temperature below the set point value, the thermo-element will open the valve and allow more flow in the circulation pipe. The valve is in equilibrium (nominal flow = calculated flow) when the water temperature has reached the value set on the valve.

The MTCV regulating characteristic is shown in fig. 13, version A.

When the water temperature is 5 °C higher than the set point value, the flow through the valve stops.

A special sealing of the thermo-element protects it against direct contact with water, which prolongs the durability of the thermoelement and at the same time secures a precise regulation.

A safety spring (fig. 6 elem. 6) protects the thermo-element from being damaged when the water temperature exceeds the value on the set point.

Design

1. Valve body

2. Spring

3. Cone

4. Thermo-element

5. O-ring

6. Safety spring

7. Setting ring

8. Setting knob

9. Plug for covering the setting

10. Cone for disinfection module

11. Safety spring

12. Plug for thermometer

13. Plug for disinfection module

2 | © Danfoss | 2019.04

Fig. 5 Example of MTCV / basic version / placement in domestic hot water system

Fig. 6 Design - basic version - A

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Data sheet MTCV - Lead free brass

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Function

Fig.7 MTCV self-acting version with automatic thermal disinfection function - B

* thermomete r is accessory

The MTCV standard version - A can easily and quickly be upgraded to the thermal disinfection function against the Legionella bacteria in hot water systems.

After removing the plug from the disinfection plug (fig. 6 elem. 13)-(this can be done during working conditions, under pressure) the thermostatic disinfection module can be mounted (fig. 9 elem. 17).

The disinfection module will control the flow according to its regulating characteristics, (fig. 13, version B) thus performing a thermal disinfection of the hot water installation.

The mounted disinfection module automatically opens a by-pass of Kv min = 0.15 m3/h, which allows flow for the disinfection. In the A version of the MTCV this by-pass is always closed in order to avoid sedimentation of dirt and calcium. The MTCV can thus be upgraded with the disinfection module even after a long period of working in the A version without risking blocking the bypass.

The regulation module in basic version A works within the temperature range 35-60 °C. When the temperature of the hot water increases above 65°C the disinfection process starts meaning the flow through the main seat of the MTCV valve stops and the bypass opens for the “disinfection flow”. The regulating function is now performed by the disinfection module, which opens the bypass when the temperature is above 65 °C.

The disinfection process is performed until a temperature of 70 °C is reached. When the hot water temperature is increased further, the flow through the disinfection bypass is reduced (the process of thermal balancing of the installation during disinfection) and when reaching 75 °C the flow stops. This is to protect the hot water installation against corrosion and sedimentation of calcium as well as to lower the risk of scalding.

A thermometer can optionally be mounted in both version A and B in order to measure and control the temperature of the circulating hot water.

Design

1-13 As described in fig. 6 14 Bypass for disinfection 15 Thermometer 16 Gasket Cu 17 Disinfecting module

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Fig. 8 Scheme of hot water installation with circulation - self acting version.

Fig. 9 Design - self-acting version with automatic

thermal disinfection function - B

Data sheet MTCV - Lead free brass

Function

Fi g.10 Version with electronically controlled disinfection process - C

The MTCV version “A” and “B” can be upgraded to an electronic regulated disinfection process (version C).

After removing the disinfection plug (fig. 6

elem. 13) the adapter can be mounted (fig. 12 elem. 21) and the thermo actuator TWA can be

mounted.

A temperature sensor PT 1000 has to be mounted in the thermometer head (fig. 12 elem. 19). Thermo-actuator and sensor are connected to the electronic regulator CCR2+ which allows an efficient and effective disinfection process in each circulation riser. The main regulation module works within the temperature range 35-60 °C. When the disinfection process/thermalwater treatment starts CCR2+ controls the flow through MTCV via thermo-actuators TWA. Benefits of an electronic regulated disinfection process with CCR2+ are:

• Providing full control over the disinfection process in each individual riser.

• Optimisation of total disinfection time.

• Optional choice of temperature for the disinfection.

• Optional choice of time for the disinfection.

• On-line measurement and monitoring of the water temperature in each individual riser.

• Enabling the possibility of connecting to the controller in the heat substation or boiler room (i.e. Danfoss ECL) or to a BMS (Modbus).

Design

1-13 As described in fig. 6

18 Bypass; (position closed) 19 Temperature sensor PT 1000 20 Gasket Cu 21 Adapter to connect thermo-

actuator TWA

Fi g. 11 - scheme of installation for disinfection and registration temperature

A) in dependent system (only se nsor S0 needed) B) depende nt system (sensor S0 and connectio n to weather or another control n eeded)

Fi g.12 Version with electronically controlled disinfection process - C

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