User Guide for Danfoss models including: VVX-B Heating Controller, VVX-B, Heating Controller, Controller
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DocumentDocumentOperating Guide Termix VVX-B 1.0 Table of Contents 1.0 Table of Contents ............................................. 1 ........................................................................ 2 2.0 Functional description...................................... 3 3.0 Safety notes..................................................... 4 3.1 Safety Notes general . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4.0 Mounting ........................................................ 5 4.1 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.2 Start-up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.3 Electrical connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 7.0 Troubleshooting .............................................. 21 7.1 Troubleshooting in general . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 7.2 Troubleshooting DHW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 7.3 Troubleshooting HE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 7.4 Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 8.0 Declaration...................................................... 27 8.1 Declaration of conformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.0 Design............................................................. 10 5.1 Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.2 Schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.0 Controls .......................................................... 12 6.1 Heating circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6.2 DHW temperature control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 6.3 Other. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 6.4 Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 | 1 Operating Guide Termix VVX-B 2 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 2.0 Functional description Indirect substation for single and multi-family houses with up to 7 flats. Application The Termix VVX-B is a complete solution for hot water and space heating with optimal safety, efficient energy transfer, service-friendly construction and a compact design. The substation is used if a heat exchanger is required or on a conversion to district heating where the existing equipment is unsuitable for direct connection. District heating (DH) The substation is prefabricated with a differential pressure controller, fitting piece and sensor pockets for insertion of a heat meter as well as strainers and ball valves. Heating (HE) The heating side consists of a plate heat exchanger, safety valve, manometer, thermometers, ball valves, drain valve, air valve, expansion vessel and circulation pump. The temperature of the heating can be controlled thermostatically or by an electronic controller with an outdoor temperature sensor. Depending on the application, different heat exchangers dimensioned for central or underfloor heating can be used. Domestic hot water (DHW) The domestic hot water is prepared in the heat exchanger and the temperature is regulated with a thermostatic control valve. The patented sensor accelerator accelerates the closing of the Danfoss AVTB valve and protects the heat exchanger against overheating and lime scale formation. The sensor accelerator helps to ensure a stable hot water temperature by varying loads, flow temperatures and differential pressure without the need for readjusting the valve. The heat exchanger cools the DH water very efficiently, thereby creating a very good operating economy. The sensor accelerator and AVTB valve also works as a bypass keeping the house supply line warm. This shortens the waiting periods during summer when the heating system is in reduced operation. AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 3 Operating Guide Termix VVX-B 3.0 Safety notes 3.1 Safety Notes general The following instructions refer to the standard design of substation. Special versions of substations are available on request. This operating manual should be read carefully before installation and start-up of the substation. The manufacturer accepts no liability for damage or faults that result from non-compliance with the operating manual. Please read and follow all the instructions carefully to prevent accidents, injury and damage to property. Assembly, start-up and maintenance work must be performed by qualified and authorized personnel only. Please comply with the instructions issued by the system manufacturer or system operator. Corrosion protection All pipes and components are made of stainless steel and brass. The maximum chloride compounds of the flow medium should not be higher than 150 mg/l. The risk of equipment corrosion increases considerably if the recommended level of permissible chloride compounds is exceeded. Energy source The substation is designed for district heating as the primary source of energy. However, also other energy sources can be used where the operating conditions allow it and always are comparable to district heating. Application The substation is designed to be connected to the house installation in a frost-free room, where the temperature does not exceed 50 °C and the humidity does not exceed 60%. Do not cover or wall up the substation or in any other way block the entrance to the station. Choice of material Choice of materials always in compliance with local legislation. Safety valve(s) We recommend mounting of safety valve(s), however, always in compliance with local regulations. Connection The substation must be equipped with features that ensure that the substation can be separated from all energy sources (also power supply). Emergency In case of danger or accidents - fire, leaks or other dangerous circumstances - interrupt all energy sources to the station if possible, and seek expert help. In case of discoloured or bad-smelling domestic hot water, close all shut-off valves on the substation, inform the operating personnel and call for expert help immediately. REACH All Danfoss A/S products fulfill the requirements in REACH. One of the obligations in REACH is to inform customers about presence of Candidate list substances if any, we hereby inform you about one substance on the candidate list: The product contains brass parts which contains lead (CAS no: 7439-92-1) in a concentration above 0.1% w/w. Storage Any storage of the substation which may be necessary prior to installation should be in conditions which are dry and heated. Authorized personnel only Assembly, start-up and maintenance work must be performed by qualified and authorized personnel only. Please observe instructions carefully To avoid injury to persons and damage to the device, it is absolutely necessary to read and observe these instructions carefully. Warning of high pressure and temperature Be aware of the installation's permissible system pressure and temperature. The maximum temperature of the flow medium in the substation is 120 °C. The maximum operating pressure of the substation is 10 bar. PN 16 versions are available on enquiry. The risk of persons being injured and equipment damaged increases considerably if the recommended permissible operating parameters are exceeded. The substation installation must be equipped with safety valves, however, always in accordance with local regulations. Warning of hot surface The substation has got hot surfaces, which can cause skin burns. Please be extremely cautious in close proximity to the substation. Power failure can result in the motor valves being stuck in open position. The surfaces of the substation can get hot, which can cause skin burns. The ball valves on district heating supply and return should be closed. Warning of transport damage Before substation installation, please make sure that the substation has not been damaged during transport. IMPORTANT - Tightening of connections Due to vibrations during transport all flange connections, screw joints and electrical clamp and screw connections must be checked and tightened before water is added to the system. After water has been added to the system and the system has been put into operation, re-tighten ALL connections. 4 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 4.0 Mounting 4.1 Mounting Installation must be in compliance with local standards and regulations. District heating (DH) - In the following sections, DH refers to the heat source which supplies the substations. A variety of energy sources, such as oil, gas or solar power, could be used as the primary supply to Danfoss substations. For the sake of simplicity, DH can be taken to mean the primary supply. Connections: 1. District heating (DH) supply 2. District heating (DH) return 3. Heating (HE) supply 4. Heating (HE) return 5. Domestic hot water (DHW) 6. Domestic cold water (DCW) Authorized personnel only Assembly, start-up and maintenance work must be performed by qualified and authorized personnel only. Connection sizes: DH + HE: DCW + DHW: G ¾" (int. thread) G ¾" (int. thread) The pipe placement can deviate from the shown drawing. Please note the markings on the station. Dimensions (mm): Without cover: H 750 x W 528 x D 360 With cover: H 800 x W 540 x D 430 Weight (approx.): 40 kg AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 5 Operating Guide Termix VVX-B 4.1.1 Installation Mounting: Adequate space Please allow adequate space around the substation for mounting and maintenance purposes. Orientation The station must be mounted so that components, keyholes and labels are placed correctly. If you wish to mount the station differently please contact your supplier. Drillings Where substations are to be wall-mounted, drillings are provided in the back mounting plate. Floor mounted units have support. Labelling Each connection on the substation is labelled. Keyhole for mounting. Before installation: Clean and rinse Prior to installation, all substation pipes and connections should be cleaned and rinsed. Tightening Due to vibration during transport, all substation connections must be checked and tightened before installation. Unused connections Unused connections and shut-off valves must be sealed with a plug. Should the plugs require removal, this must only be done by an authorized service technician. Installation: Strainer If a strainer is supplied with the station it must be fitted according to schematic diagram. Please note that the strainer may be supplied loose. Connections Internal installation and district heating pipes connections must be made using threaded, flanged or welded connections. 6 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 4.2 Start-up Start-up, Indirect heating Filling: 1: First fill When carrying out first fill, the heat exchanger must be slowly filled with water until it reaches working pressure. 2: Pressure gauge The HE pressure gauge indicates the pressure of the HE system. This instruction must be followed strictly, to avoid dangerous situations. 3: Supply hose A ball valve with plug is installed in the HE return line. To fill the system, the ball valve must first be closed, the plug removed and a supply hose connected. On re-opening the ball valve, system fill can commence. 4: Pre-pressure When filling the system with water, the pressure gauge should be observed closely. The expansion vessel is supplied pre-pressurised to 0.5 bar. The pre-pressure required at each substation will depend on system head (the distance between the lowest and highest point in the system), for example: 5: Filling stop Filling must stop when the pressure gauge shows a pressure approximately 1-2 bar higher than the pre-pressure setting. The ball valve is then closed, the hose removed and the plug put back in. Re-tighten connections After water has been added to the system and the system has been put into operation, re-tighten ALL connections. Pump The pump must be switched off during system fill. Height (m) 05 5 10 10 15 15 20 Pressure (bar) 0,5 1,0 1,5 2,0 Start-up: 1: Pump speed Set the pump to highest speed before start-up. 2: Start pump Start the pump and heat through the system. 3: Open shut-off valves The shut-off valves should then be opened and the unit observed as it enters service. Visual checking should confirm temperatures, pressures, acceptable thermal expansion and absence of leakage. If the heat exchanger operates in accordance with design, it can be put to regular use. 4: Vent system Switch off the pump and vent the installation after the radiators have been warmed up. 5: Adjust pump speed Set the pump to the lowest speed consistent with comfort and electricity consumption. Normally the change-over switch is set in the mid position (default). However for systems with under floor heating or single pipe loop systems, it may be necessary to turn the change-over switch upwards. Higher pump speeds are only used if the heating requirement increases. AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 7 Operating Guide Termix VVX-B Under floor heating: Pump stop function If the substation is used in connection with under floor heating, the circulation pump must be connected to the pump stop function in the under floor heating controller. The pump must be stopped if all under floor heating circuits are closed. Warranty If this is not possible, then flow must be continued through the by-pass. Failing this, the pump will be at risk of seizure and any remaining warranty will be withdrawn. Summer operation: Switch off pump In summer the circulation pump must be switched off and the shut-off valve to HE supply closed. Running pump bi-weekly It is recommended to start up the circulation pump (for 2 minutes) once a month during summer; the shut-off valve of the HE supply must be shut. Electronic controller Most electronic controllers will start up the pump automatically (please note manufacturer´s instructions). 8 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 4.3 Electrical connections Before making electrical connections, please note the following: Safety notes Please read the relevant parts of the safety notes. 230 V The substation must be connected to 230 V AC and earth. Potential bonding Potential bonding should be carried out according to 60364-4-41:2007 and IEC 60364-5-54:2011. Bonding point on the mounting plate below right corner marked with earth symbol. Disconnection The substation must be electrically connected so that it can be disconnected for repairs. Outdoor temperature sensor Outdoor sensors should be mounted so as to avoid exposure to direct sunlight. They should not be placed close to doors, windows or ventilation outlets. The outdoor sensor must be connected to the station on the terminal block under the electronic control. Authorized electrician Electrical connections must be made by an authorized electrician only. Local standards Electrical connections must be made in accordance with current regulations and local standards. AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 9 Operating Guide Termix VVX-B 5.0 Design 5.1 Design Your substation might look different than the substation shown. Design description A Heat exchanger, HE B Heat exchanger, DHW 1A Summer valve 4 Safety valve 7A Thermostatic valve, heating 7B Thermostatic valve, DHW 9 Strainer 10 Circulator pump 14 Sensor pocket, energy meter 20 Filling/drain valve 26 Pressure gauge 31 Differential pressure controller 38 Expansion tank 41 Fitting piece, energy meter 48 Air vent, manual 10 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 5.2 Schematic diagram DHW DCW DH Supply HE Supply DH Return HE Return Your substation might look different than the schematic diagram shown. Schematic description A Heat exchanger, HE B Heat exchanger, DHW 1 Ball valve 4 Safety valve 7 Thermostatic valve 9 Strainer 10 Circulator pump 14 Sensor pocket, energy meter 18 Thermometer 20 Filling/drain valve 24 Delivered loose with unit 26 Pressure gauge DHW: DCW: DH Supply: DH Return: HE Supply: HE Return: Domestic Hot Water Domestic Cold Water District Heating Supply District Heating Return Heating Supply Heating Return 31 Differential pressure controller 38 Expansion tank 41 Fitting piece, energy meter 48 Air vent, manual 5.2.1 Technical parameters Technical parameters Nominal pressure: Max. DH supply temperature: Min. DCW static pressure: Brazing material (HEX): Heat exchangers test pressure: Sound level: PN 10 (PN 16 versions are available on enquiry) 120 °C 0.5 bar Copper 30 bar 55 dB AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 11 Operating Guide Termix VVX-B 6.0 Controls 6.1 Heating circuit 6.1.1 Differential pressure controller The differential pressure controller smooths out the fluctuations in pressure arriving from the district heating network. The operating pressure in the substation is thus held steady. 6.1.2 HE temperature control The HE flow temperature in the heating circuit is controlled by the HE temperature controller. 6.1.3 RAVK controller RAVK controller (25-65 °C). The temperature setting is as follows: 1 = 25 °C 2 = 35 °C 3 = 45 °C 4 = 55 °C 5 = 65 °C The values are intended as a guide. Thermostatic control The temperature of the HE flow line is adjusted as follows: To increase temperature, turn the handle on the thermostatic controller to select a higher number. To decrease temperature, turn the handle on the thermostatic controller to select a lower number. 12 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 6.1.4 AVTB controller (30100 °) The temperature setting is as follows: 1 = 35 °C 2 = 55 °C 3 = 75 °C 4 = 95 °C 5 = 100 °C The values are intended as a guide. Thermostatic control The temperature of the HE flow line is adjusted as follows: To increase temperature, turn the handle on the thermostatic controller to select a higher number. To decrease temperature, turn the handle on the thermostatic controller to select a lower number. 6.1.5 Flow controller with integrated control valve The controller is a self-acting flow controller with integrated control valve. The controller closes when set max. flow is exceeded and can be used in combination with Danfoss electrical actuators with or with out safety function. Spring return motor can be used as safety function by power failure. 6.1.6 Electronic control Substations with electronic control must be set in accordance with manufacturer´s instructions. Where the room temperature is controlled by radiator thermostats, it is recommended that thermostats be set for minimum temperature in each room. AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 13 Operating Guide Termix VVX-B 6.1.7 Outdoor temperature sensor (ESMT) Outdoor sensors should be mounted so as to avoid exposure to direct sunlight. They should not be placed close to doors, windows or ventilation outlets. 6.1.8 TP7000 TP7000 electronic 7 day programmable room thermostat. Signals from the room thermostat can be used to control zone valves. 6.1.9 Circulator pump UPM3 UPM3 Pumps can be controlled in constant pressure, proportional pressure or constant speed mode defined by the means of a smart user interface. The variable speed modulating modes allow the pump to match its performance to the system requirements, helping to reduce noise when thermostatic valves are closing down. Energy labelling class A 14 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 6.1.10 Grundfos UPM3 AUTO instructions Control mode Each push on the button switches to the next program setting. The choice of operation mode depends on the type of heating system and the pressure loss in the system. Settings Function: Proportional pressure Auto adapt Constant pressure Auto adapt Proportional pressure 1 Proportional pressure 2 Proportional pressure 3 -- MAX Constant pressure 1 Constant pressure 2 Constant pressure 3 -- MAX Constant Curve 1 Constant Curve 2 Constant Curve 3 -- MAX Recommended for: 2-pipe systems 1-pipe systems Under floor heating Alarm status Function: Power Supply failure Blocked Supply voltage low Electrical error Recommended for: Green Green Yellow Yellow Yellow Red Green Yellow Yellow Yellow AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 15 Operating Guide Termix VVX-B 6.1.11 HE pressure gauge The HE pressure gauge indicates the pressure of the HE system. 16 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 6.2 DHW temperature control DHW temperature control There are various types of DHW temperature control used in Danfoss substations. DHW temperature should be adjusted to 45-50 °C, as this provides optimal utilisation of DH water. At DHW temperatures above 55 °C, the possibility of lime scale deposits increases significantly. 6.2.1 AVTB controller (2060 °) The temperature setting is as follows: 1 = 20 °C 2 = 35 °C 3 = 50 °C 4 = 60 °C 5 = 70 °C The values are intended as a guide. The AVTB operates at its best at DH supply temperatures of up to 90 °C. Thermostatic control DHW temperature is adjusted as follows: To increase temperature, turn the handle on the thermostatic controller to select a higher number. To decrease temperature, turn the handle on the thermostatic controller to select a lower number. 6.2.2 Electric 2way motorized valve Actuators with or without safety function are available for 3-point controls. Spring-return actuators can be used to provide safety shut-off in the event of power failure. AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 17 Operating Guide Termix VVX-B 6.3 Other 6.3.1 Safety valve The purpose of the safety valve is to protect the substation from excessive pressure. The blow-off pipe from the safety valve must not be closed. The blow-off pipe outlet should be placed so that it discharges freely and it is possible to observe any dripping from the safety valve. It is recommended to check the operation of safety valves at intervals of 6 months. This is done by turning the valve head in direction indicated. 6.3.2 Strainer Strainers should be cleaned regularly by authorized personnel. The frequency of cleaning would depend on operating conditions and the manufacturer's instructions. 6.3.3 GTU Pressure Equalizer The GTU Pressure Equalizer absorbs the expansion on the secondary side of the Termix water heaters and can be used as a substitute to the safety valve. Furthermore the pressure equalizer absorbs a possible increase in pressure, so a discharge outlet is omitted. The GTU Pressure Equalizer may not be applied in systems with hot water circulation. 18 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 6.3.4 Fitting piece The substation is equipped with a fitting piece for energy meter. Assembly of energy meters: 1: Close ball valves Close the ball valves on DH Supply and DH Return, if there is water on the system. 2: Loosen nuts Loosen the nuts on the fitting piece. 3: Remove fitting piece Remove the fitting piece and replace it with the energy meter. Do not forget the gaskets. 4: Tighten connections After mounting of the energy meter remember to check and tighten all threaded connections. Sensor pocket, energy meter The sensors of the energy meter is mounted in the sensor pockets. AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 19 Operating Guide Termix VVX-B 6.4 Maintenance The substation requires little monitoring, apart from routine checks. It is recommended to read the energy meter at regular intervals, and to write down the meter readings. Regular inspections of the substation according to this Instruction are recommended, which should include: Strainers Cleaning of strainers. Meters Checking of all operating parameters such as meter readings. Temperatures Checking of all temperatures, such as DH supply temperature and DHW temperature. Connections Checking all connections for leakages. Safety valves The operation of the safety valves should be checked by turning the valve head in the indicated direction. Venting Checking that the system is thoroughly vented. Inspections should be carried out minimum every two years. Spare parts can be ordered from Danfoss. Please ensure that any enquiry includes the substation serial number. Authorized personnel only Assembly, start-up and maintenance work must be performed by qualified and authorized personnel only. 20 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 7.0 Troubleshooting 7.1 Troubleshooting in general In the event of operating disturbances, the following basic features should be checked before carrying out actual troubleshooting: · the substation is connected to electricity, · the strainer on the DH supply pipe is clean, · the supply temperature of the DH is at the normal level (summer, at least 60 °C - winter, at least 70 °C), · the differential pressure is equal to or higher than the normal (local) differential pressure in the DH network if in doubt, ask the DH plant supervisor, · pressure on the system - check the HE pressure gauge. Authorized personnel only Assembly, start-up and maintenance work must be performed by qualified and authorized personnel only. AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 21 Operating Guide Termix VVX-B 7.2 Troubleshooting DHW Problem Too little or no DHW. Hot water in some taps but not in all. Tap temperature too high; DHW tap load too high. Temperature drop during tapping. Thermostatic control valve does not close Possible cause Solution Strainer in supply or return line clogged. Clean strainer(s). DHW circulation pump out of order or with Check circulation pump. too low setting. Defective or clogged non-return valve. Replace clean. No electricity. Check. Wrong setting of automatic controls, if any. To adjust an electronic controller for DHW, pls. note enclosed instructions for electronic controller. Scaling of the plate heat exchanger. Replace rinse out. Defective motorized valve. Check (use manual function) replace. Defective temperature sensors. Check replace. Defective controller. Check replace. DCW is being mixed with the DHW, e.g. in a Check replace. defective thermostatic mixing valve. Defective or clogged non-return valve on Replace clean. circulation valve. Thermostatic valve adjusted to a too high Check set. level. Scaling of the plate heat exchanger. Replace rinse out. Larger DHW flow than the substation has Reduce DHW flow. been designed for. Temperature difference between DH supply and DHW set point too low. Lower the set point temperature or increase the DH supply temperature. 22 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 7.3 Troubleshooting HE Problem Too little or no heat. Uneven heat distribution. DH supply temperature too high. DH supply temperature too low. Possible cause Solution Strainer clogged in DH or HE circuit (radiator circuit). Clean gate/strainer(s). The filter in the energy meter on DH circuit Clean the filter (after consulting the DH clogged. plant operator). Defective or wrongly adjusted differential pressure controller. Check the operation of the differential pressure controller clean the valve seat if required. Sensor defective or possibly dirt in the valve housing. Check the operation of the thermostat clean the valve seat if required. Automatic controls, if any, wrongly set or defective - possibly power failure. Check if the setting of the controller is correct see separate instructions. Check the power supply. Temporary setting of motor to "manual" control see instructions on automatic controls. Pump out of operation. Check if the pump is receiving power and that it turns. Check if there is air trapped in the pump housing see pump manual. The pump is set at too low speed of rotation. Set the pump at higher speed of rotation. Pressure drop the pressure drop on the radiator circuit shows lower than recommended operating pressure. Fill water on the system and check the functioning of the pressure expansion vessel if required. Air pockets in the system. Vent the installation thoroughly. Limiting of the return temperature adjusted Adjust according to instructions. too low. Defective radiator valves. Check replace. Uneven heat distribution in building Adjust/install balancing valves. because of incorrectly set balancing valves, or because there are no balancing valves. Diameter of pipe to substation too small or Check pipe dimensions. branch pipe too long. Air pockets in the system. Vent the installation thoroughly. Wrong setting of thermostat or of automatic controls, if any. Adjust automatic controls, see instructions for automatic controls. Defective controller. The controller does not react as it should according to the instructions. Call automatic controls manufacturer or replace the regulator. Defective sensor on self-acting thermostat. Replace thermostat or sensor only. Wrong setting of automatic controls, if any. Adjust automatic controls see instructions for automatic controls. Defective controller. The controller does not react as it should according to the instructions. Call in automatic controls manufacturer or replace controller. Defective sensor on self-acting thermostat. Replace thermostat or sensor only. Wrong placement/fitting of outdoor temperature sensor. Adjust location of outdoor temperature sensor. Strainer clogged. Clean gate/strainer. AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 23 Operating Guide Termix VVX-B Too high DH return temperature. Noise in system. Heat load too high. Too small heating surface/too small radiators compared to the total heating requirement of the building. Increase total heating surface. Poor utilization of existing heating surface. Defective sensor on self-acting thermostat. Make sure the heat is distributed evenly across the full heating surface open all radiators and keep the radiators in the system from heating up at the bottom. It is extremely important to keep the supply temperature to the radiators as low as possible, while maintaining a reasonable level of comfort. The system is single pipe loop. The system should feature electronic controls as well as return sensors. Pump pressure too high. Adjust pump to a lower level. Air in system. Vent the system. Defective or incorrectly set radiator valve(s). Check set/replace. Single pipe loop systems require special one-pipe radiator valves. Dirt in the motorized valve or in the differential pressure controller. Check clean out. Defective motorized valve, sensor or automatic controller. Check replace. Electronic controller not adjusted correctly. Adjust according to instructions. Pump pressure too high. Adjust pump to a lower level. Defective motorized valve, sensor or electronic controller. Check replace. 24 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 7.4 Disposal Disposal note This symbol on the product indicates that it may not be disposed of as household waste.. It must be handed over to the applicable take-back scheme for the recycling of electrical and electronic equipment. · Dispose of the product through channels provided for this purpose. · Comply with all local and currently applicable laws and regulations. AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 25 Operating Guide Termix VVX-B 26 | © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001 Operating Guide Termix VVX-B 8.0 Declaration 8.1 Declaration of conformity AQ110586477332en-020601 / LUK4040001 © Danfoss | 2023.10 | 27 Operating Guide Termix VVX-B 28| © Danfoss | 2023.10 AQ110586477332en-020601 / LUK4040001Danfoss A/S GPL Ghostscript 10.03.1